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<?xml-stylesheet type="text/xsl" href="https://community.element14.com/cfs-file/__key/system/syndication/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/"><channel><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications</link><description /><dc:language>en-US</dc:language><generator>Telligent Community 12</generator><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications</link><pubDate>Tue, 11 Jan 2022 18:01:05 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Current Revision posted to Documents by dychen on 1/11/2022 6:01:05 PM&lt;br /&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of stable clocking in network synchronization, especially with arrival of 5G, and techniques that engineers are using to meet the challenges.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability, as well as cost, are important considerations for the end product.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can influence oscillator performance. 5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Devices mounted outdoors are also subjected to large temperature ranges, including extreme heat and cold. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;Cost and availability are also concerns, as well as size, heat, and power considerations. TCXO and MEMS-based oscillators are replacing other types due to their performance and affordability, however, low-cost MEMS oscillators can introduce additional constraints. They may not react well to physical-layer rearrangement, and typically do not support the necessary bandwidth for PTP G.8275.2, limiting them to the lower-bandwidth used in the G.8275.1 PTP profile.&lt;/p&gt;
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&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 2 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/p&gt;
&lt;p&gt;TCXOs are well-suited for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems. Wireless infrastructure equipment is becoming physically smaller, enabling it to be installed in locations that are space constrained. Such locations may also be remote and have limited connectivity to power sources, requiring equipment to maintain low power consumption. TCXOs provide the necessary performance, in a small package with low power consumption. Since TCXOs are temperature-compensated, they are able to adapt to and maintain their stability through temperature changes.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Oscillators&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:240px;" alt="ASGTX5PAF1-156.2500T2" src="/e14/assets/main/2021/ASGTX5t.jpg" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: Abracon ASGTX5PAF1-156.2500T2&lt;br /&gt;&amp;nbsp;&lt;a id="e14-product-link-50d2f" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-button" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('50d2f'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;Buy Now&lt;/a&gt; &lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TCXO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-c7953" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('c7953'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-429ae" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('429ae'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-cded3" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('cded3'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: &lt;a title="Abracon ASGTX5" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;amp;COM=referral-cmty-handler-techspotlight-txcos" rel="noopener noreferrer" target="_blank"&gt;Abracon ASGTX5&lt;/a&gt; TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;Abracon has also recently introduced the Ultra-Performance TCXO series (AST3TDA), offering clocks as stable as &amp;plusmn;50 ppb at +105&amp;ordm;C, in a 7.0 mm x 5.0 mm x 2.2 mm package.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO and Ultra-Performance TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
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&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/14</link><pubDate>Wed, 05 Jan 2022 16:05:02 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 14 posted to Documents by dychen on 1/5/2022 4:05:02 PM&lt;br /&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of stable clocking in network synchronization, especially with arrival of 5G, and techniques that engineers are using to meet the challenges.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability, as well as cost, are important considerations for the end product.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can influence oscillator performance. 5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Devices mounted outdoors are also subjected to large temperature ranges, including extreme heat and cold. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;Cost and availability are also concerns, as well as size, heat, and power considerations. TCXO and MEMS-based oscillators are replacing other types due to their performance and affordability, however, low-cost MEMS oscillators can introduce additional constraints. They may not react well to physical-layer rearrangement, and typically do not support the necessary bandwidth for PTP G.8275.2, limiting them to the lower-bandwidth used in the G.8275.1 PTP profile.&lt;/p&gt;
&lt;div style="background-color:#fafafa;border:1px solid #898989;float:right;margin:12px 5px 12px;padding:8px 12px 18px;width:200px;"&gt;
&lt;p style="border-bottom:1px solid #898989;color:#007fac;font-size:20px;font-weight:bold;margin-bottom:6px;padding-bottom:2px;"&gt;Oscillators&lt;/p&gt;
&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;span &gt;&lt;a class="e14-button e14-button--primary e14-button--large" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;COM=referral-cmty-handler-techspotlight-txcos" title="Shop Now" title="Shop Now" target="_blank"&gt;Shop Now&lt;/a&gt;&lt;/span&gt;&lt;/span&gt;&lt;/strong&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 2 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/p&gt;
&lt;p&gt;TCXOs are well-suited for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems. Wireless infrastructure equipment is becoming physically smaller, enabling it to be installed in locations that are space constrained. Such locations may also be remote and have limited connectivity to power sources, requiring equipment to maintain low power consumption. TCXOs provide the necessary performance, in a small package with low power consumption. Since TCXOs are temperature-compensated, they are able to adapt to and maintain their stability through temperature changes.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Oscillators&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:240px;" alt="ASGTX5PAF1-156.2500T2" src="/e14/assets/main/2021/ASGTX5t.jpg" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: Abracon ASGTX5PAF1-156.2500T2&lt;br /&gt;&amp;nbsp;&lt;a id="e14-product-link-a76d1" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-button" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('a76d1'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;Buy Now&lt;/a&gt; &lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-d694a" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('d694a'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-ee016" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('ee016'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-c6684" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('c6684'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: &lt;a title="Abracon ASGTX5" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;amp;COM=referral-cmty-handler-techspotlight-txcos" rel="noopener noreferrer" target="_blank"&gt;Abracon ASGTX5&lt;/a&gt; TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;Abracon has also recently introduced the Ultra-Performance TCXO series (AST3TDA), offering clocks as stable as &amp;plusmn;50 ppb at +105&amp;ordm;C, in a 7.0 mm x 5.0 mm x 2.2 mm package.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO and Ultra-Performance TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/13</link><pubDate>Wed, 05 Jan 2022 16:02:08 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 13 posted to Documents by dychen on 1/5/2022 4:02:08 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p style="font-size:12px;padding-bottom:5px;"&gt;&lt;em&gt;sponsored by&lt;/em&gt;&lt;/p&gt;
&lt;img class="nolightbox" alt="logo" src="/e14/assets/main/mfg-group-assets/AbraconLogoVert.jpg" width="150px" /&gt;&lt;/div&gt;
&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of stable clocking in network synchronization, especially with arrival of 5G, and techniques that engineers are using to meet the challenges.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability, as well as cost, are important considerations for the end product.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can influence oscillator performance. 5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Devices mounted outdoors are also subjected to large temperature ranges, including extreme heat and cold. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;Cost and availability are also concerns, as well as size, heat, and power considerations. TCXO and MEMS-based oscillators are replacing other types due to their performance and affordability, however, low-cost MEMS oscillators can introduce additional constraints. They may not react well to physical-layer rearrangement, and typically do not support the necessary bandwidth for PTP G.8275.2, limiting them to the lower-bandwidth used in the G.8275.1 PTP profile.&lt;/p&gt;
&lt;div style="background-color:#fafafa;border:1px solid #898989;float:right;margin:12px 5px 12px;padding:8px 12px 18px;width:200px;"&gt;
&lt;p style="border-bottom:1px solid #898989;color:#007fac;font-size:20px;font-weight:bold;margin-bottom:6px;padding-bottom:2px;"&gt;Oscillators&lt;/p&gt;
&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;span &gt;&lt;a class="e14-button e14-button--primary e14-button--large" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;COM=referral-cmty-handler-techspotlight-txcos" title="Shop Now" title="Shop Now" target="_blank"&gt;Shop Now&lt;/a&gt;&lt;/span&gt;&lt;/span&gt;&lt;/strong&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p style="color:#f17c0e;font-size:15px;"&gt;&lt;strong&gt;&lt;em&gt;Don&amp;#39;t forget to &lt;a href="#poll"&gt;take our poll&lt;/a&gt;.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;/div&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 2 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/p&gt;
&lt;p&gt;TCXOs are well-suited for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems. Wireless infrastructure equipment is becoming physically smaller, enabling it to be installed in locations that are space constrained. Such locations may also be remote and have limited connectivity to power sources, requiring equipment to maintain low power consumption. TCXOs provide the necessary performance, in a small package with low power consumption. Since TCXOs are temperature-compensated, they are able to adapt to and maintain their stability through temperature changes.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Oscillators&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:240px;" alt="ASGTX5PAF1-156.2500T2" src="/e14/assets/main/2021/ASGTX5t.jpg" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: Abracon ASGTX5PAF1-156.2500T2&lt;br /&gt;&amp;nbsp;&lt;a id="e14-product-link-3ef69" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-button" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('3ef69'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;Buy Now&lt;/a&gt; &lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-21edf" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('21edf'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-caa17" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('caa17'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-8482b" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('8482b'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: &lt;a title="Abracon ASGTX5" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;amp;COM=referral-cmty-handler-techspotlight-txcos" rel="noopener noreferrer" target="_blank"&gt;Abracon ASGTX5&lt;/a&gt; TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;Abracon has also recently introduced the Ultra-Performance TCXO series (AST3TDA), offering clocks as stable as &amp;plusmn;50 ppb at +105&amp;ordm;C, in a 7.0 mm x 5.0 mm x 2.2 mm package.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO and Ultra-Performance TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/12</link><pubDate>Wed, 05 Jan 2022 16:01:09 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 12 posted to Documents by dychen on 1/5/2022 4:01:09 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of stable clocking in network synchronization, especially with arrival of 5G, and techniques that engineers are using to meet the challenges.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability, as well as cost, are important considerations for the end product.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can influence oscillator performance. 5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Devices mounted outdoors are also subjected to large temperature ranges, including extreme heat and cold. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;Cost and availability are also concerns, as well as size, heat, and power considerations. TCXO and MEMS-based oscillators are replacing other types due to their performance and affordability, however, low-cost MEMS oscillators can introduce additional constraints. They may not react well to physical-layer rearrangement, and typically do not support the necessary bandwidth for PTP G.8275.2, limiting them to the lower-bandwidth used in the G.8275.1 PTP profile.&lt;/p&gt;
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&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 2 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/p&gt;
&lt;p&gt;TCXOs are well-suited for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems. Wireless infrastructure equipment is becoming physically smaller, enabling it to be installed in locations that are space constrained. Such locations may also be remote and have limited connectivity to power sources, requiring equipment to maintain low power consumption. TCXOs provide the necessary performance, in a small package with low power consumption. Since TCXOs are temperature-compensated, they are able to adapt to and maintain their stability through temperature changes.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Oscillators&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:240px;" alt="ASGTX5PAF1-156.2500T2" src="/e14/assets/main/2021/ASGTX5t.jpg" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: Abracon ASGTX5PAF1-156.2500T2&lt;br /&gt;&amp;nbsp;&lt;a id="e14-product-link-b1298" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-button" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('b1298'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;Buy Now&lt;/a&gt; &lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-feacc" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('feacc'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-b495c" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('b495c'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-802a1" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('802a1'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: &lt;a title="Abracon ASGTX5" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;amp;COM=referral-cmty-handler-techspotlight-txcos" rel="noopener noreferrer" target="_blank"&gt;Abracon ASGTX5&lt;/a&gt; TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;Abracon has also recently introduced the Ultra-Performance TCXO series (AST3TDA), offering clocks as stable as &amp;plusmn;50 ppb at +105&amp;ordm;C, in a 7.0 mm x 5.0 mm x 2.2 mm package.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO and Ultra-Performance TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
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&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/11</link><pubDate>Tue, 21 Dec 2021 16:42:08 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 11 posted to Documents by dychen on 12/21/2021 4:42:08 PM&lt;br /&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;div style="background-color:#fafafa;border:1px solid #898989;float:right;margin:12px 5px 12px;padding:8px 12px 18px;width:200px;"&gt;
&lt;p style="border-bottom:1px solid #898989;color:#007fac;font-size:20px;font-weight:bold;margin-bottom:6px;padding-bottom:2px;"&gt;Oscillators&lt;/p&gt;
&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
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&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:240px;" alt="ASGTX5PAF1-156.2500T2" src="/e14/assets/main/2021/ASGTX5t.jpg" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5PAF1-156.2500T2&lt;br /&gt;&amp;nbsp;&lt;a id="e14-product-link-01f54" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-button" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('01f54'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;Buy Now&lt;/a&gt; &lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 5 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-dc058" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('dc058'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-2b96c" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('2b96c'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-d85e2" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('d85e2'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 5: &lt;a title="Abracon ASGTX5" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;amp;COM=referral-cmty-handler-techspotlight-txcos" rel="noopener noreferrer" target="_blank"&gt;Abracon ASGTX5&lt;/a&gt; TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/10</link><pubDate>Tue, 21 Dec 2021 16:40:39 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 10 posted to Documents by dychen on 12/21/2021 4:40:39 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;div style="float:right;margin-bottom:5px;margin-left:8px;width:160px;"&gt;
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&lt;img class="nolightbox" alt="logo" src="/e14/assets/main/mfg-group-assets/AbraconLogoVert.jpg" width="150px" /&gt;&lt;/div&gt;
&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;div style="background-color:#fafafa;border:1px solid #898989;float:right;margin:12px 5px 12px;padding:8px 12px 18px;width:200px;"&gt;
&lt;p style="border-bottom:1px solid #898989;color:#007fac;font-size:20px;font-weight:bold;margin-bottom:6px;padding-bottom:2px;"&gt;Oscillators&lt;/p&gt;
&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;span &gt;&lt;a class="e14-button e14-button--primary e14-button--large" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;COM=referral-cmty-handler-techspotlight-txcos" title="Shop Now" title="Shop Now" target="_blank"&gt;Shop Now&lt;/a&gt;&lt;/span&gt;&lt;/span&gt;&lt;/strong&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p style="color:#f17c0e;font-size:15px;"&gt;&lt;strong&gt;&lt;em&gt;Don&amp;#39;t forget to &lt;a href="#poll"&gt;take our poll&lt;/a&gt;.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;
&lt;/div&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="ASGTX5PAF1-156.2500T2" src="/e14/assets/main/2021/ASGTX5t.jpg" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5PAF1-156.2500T2&lt;/p&gt;
&lt;p&gt;&lt;a id="e14-product-link-42338" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-button" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('42338'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;Buy Now&lt;/a&gt; &lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 5 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-f7a98" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('f7a98'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-27af5" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('27af5'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-54671" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('54671'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 5: &lt;a title="Abracon ASGTX5" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;amp;COM=referral-cmty-handler-techspotlight-txcos" rel="noopener noreferrer" target="_blank"&gt;Abracon ASGTX5&lt;/a&gt; TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
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&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
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&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/9</link><pubDate>Mon, 20 Dec 2021 23:26:47 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 9 posted to Documents by dychen on 12/20/2021 11:26:47 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;div style="background-color:#fafafa;border:1px solid #898989;float:right;margin:12px 5px 12px;padding:8px 12px 18px;width:200px;"&gt;
&lt;p style="border-bottom:1px solid #898989;color:#007fac;font-size:20px;font-weight:bold;margin-bottom:6px;padding-bottom:2px;"&gt;Oscillators&lt;/p&gt;
&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;span &gt;&lt;a class="e14-button e14-button--primary e14-button--large" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;COM=referral-cmty-handler-techspotlight-txcos" title="Shop Now" title="Shop Now" target="_blank"&gt;Shop Now&lt;/a&gt;&lt;/span&gt;&lt;/span&gt;&lt;/strong&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;/div&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-28d25" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('28d25'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-a2044" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('a2044'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-884fc" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('884fc'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: &lt;a title="Abracon ASGTX5" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;amp;COM=referral-cmty-handler-techspotlight-txcos" rel="noopener noreferrer" target="_blank"&gt;Abracon ASGTX5&lt;/a&gt; TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/8</link><pubDate>Mon, 20 Dec 2021 23:21:54 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 8 posted to Documents by dychen on 12/20/2021 11:21:54 PM&lt;br /&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;div style="background-color:#fafafa;border:1px solid #898989;float:right;margin:12px 5px 12px;padding:8px 12px 18px;width:200px;"&gt;
&lt;p style="border-bottom:1px solid #898989;color:#007fac;font-size:20px;font-weight:bold;margin-bottom:6px;padding-bottom:2px;"&gt;Oscillators&lt;/p&gt;
&lt;p&gt;Shop our wide variety of &lt;strong&gt;TCXOs&amp;nbsp;by Abracon&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;span &gt;&lt;a class="e14-button e14-button--primary e14-button--large" href="https://referral.element14.com/OrderCodeView?url=%2Fsearch%3Fst%3Dabracon%2520tcxo&amp;COM=referral-cmty-handler-techspotlight-txcos" title="Shop Now" title="Shop Now" target="_blank"&gt;Shop Now&lt;/a&gt;&lt;/span&gt;&lt;/span&gt;&lt;/strong&gt;&lt;strong&gt;&lt;span style="color:#ff0000;"&gt;&lt;/span&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp;&amp;nbsp;&lt;a id="e14-product-link-27d76" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('27d76'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; ,&amp;nbsp;&lt;a id="e14-product-link-cd366" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('cd366'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and&amp;nbsp;&lt;a id="e14-product-link-31233" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('31233'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt; &amp;nbsp;are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
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&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/7</link><pubDate>Mon, 20 Dec 2021 23:17:16 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 7 posted to Documents by dychen on 12/20/2021 11:17:16 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations.&amp;nbsp; &lt;a id="e14-product-link-49f63" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501710&amp;nsku=80AH1554&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('49f63'));" data-farnell="3501710" data-newark="80AH1554" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-250.0000&lt;/a&gt; , &lt;a id="e14-product-link-b9604" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501706RL&amp;nsku=80AH1568&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('b9604'));" data-farnell="3501706RL" data-newark="80AH1568" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5PAF1-156.2500T2&lt;/a&gt; , and &lt;a id="e14-product-link-a6ed6" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="link" href="https://referral.element14.com/OrderCodeView?fsku=3501708&amp;nsku=80AH1544&amp;COM=e14c-noscript&amp;CMP=e14c-noscript&amp;osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_POPUP_OPEN"class="e14-embedded e14_shopping-cart-far e14-link" onclick="event.preventDefault();e14.func.displayProduct(e14.meta.user.country, this, 'embedded-link', e14.func.getProductLinkJSON('a6ed6'));" data-farnell="3501708" data-newark="80AH1544" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" &gt;ASGTX5DAF1-125.0000&lt;/a&gt;  are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/6</link><pubDate>Mon, 20 Dec 2021 23:01:01 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>pchan</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 6 posted to Documents by pchan on 12/20/2021 11:01:01 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations. ASGTX5DAF1-250.0000, ASGTX5PAF1-156.2500T2, and ASGTX5DAF1-125.0000 are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;vertical-align:middle;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:330px;vertical-align:middle;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:286px;vertical-align:middle;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/5</link><pubDate>Mon, 20 Dec 2021 22:59:32 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>pchan</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 5 posted to Documents by pchan on 12/20/2021 10:59:32 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:530px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram1.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:550px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/TSdec2421_diagram3.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations. ASGTX5DAF1-250.0000, ASGTX5PAF1-156.2500T2, and ASGTX5DAF1-125.0000 are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-width:300px;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/TSdec2421_diagram4a.png" /&gt; &lt;img loading="lazy" style="max-width:300px;" alt="ASGTX5 Test Circuits 2" src="/e14/assets/main/2021/TSdec2421_diagram4b.png" /&gt; &lt;img loading="lazy" style="max-width:256px;" alt="ASGTX5 Test Circuits 3" src="/e14/assets/main/2021/TSdec2421_diagram4c.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/4</link><pubDate>Mon, 20 Dec 2021 15:09:05 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 4 posted to Documents by dychen on 12/20/2021 3:09:05 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;img class="nolightbox" alt="logo" src="/e14/assets/main/mfg-group-assets/AbraconLogoVert.jpg" width="150px" /&gt;&lt;/div&gt;
&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/fig1_RAN.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; Image Source: Embedded Computing Design&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/fig3_TCXO.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; Image Source: Electronics Notes&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations. ASGTX5DAF1-250.0000, ASGTX5PAF1-156.2500T2, and ASGTX5DAF1-125.0000 are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/fig4_testcircuits.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; Image Source: Abracon&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/3</link><pubDate>Fri, 17 Dec 2021 22:08:33 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 3 posted to Documents by dychen on 12/17/2021 10:08:33 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/fig1_RAN.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators"&gt;&lt;em&gt;https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators"&gt;&lt;em&gt;https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/fig3_TCXO.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; &lt;a href="https://www.electronics-notes.com/articles/electronic_components/quartz-crystal-xtal/tcxo-temperature-compensated-crystal-xtal-oscillator.php"&gt;https://www.electronics-notes.com/articles/electronic_components/quartz-crystal-xtal/tcxo-temperature-compensated-crystal-xtal-oscillator.php&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations. ASGTX5DAF1-250.0000, ASGTX5PAF1-156.2500T2, and ASGTX5DAF1-125.0000 are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/fig4_testcircuits.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://abracon.com/datasheets/ASGTX5.pdf"&gt;&lt;em&gt;https://abracon.com/datasheets/ASGTX5.pdf&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;a name="poll"&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;p align="center"&gt;[Please visit the site to access the poll]&lt;/p&gt;&lt;/p&gt;
&lt;p&gt;&lt;a name="discussion"&gt;&lt;/a&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: synchronization, mimo, 5g, clock, digital, tech spotlight, oscillator, abracon, RAN, network, jitter&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/2</link><pubDate>Fri, 17 Dec 2021 21:03:27 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 2 posted to Documents by dychen on 12/17/2021 9:03:27 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
&lt;table style="background-color:#eee;" border="1" cellpadding="5" cellspacing="0" width="75%"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/fig1_RAN.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators"&gt;&lt;em&gt;https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators"&gt;&lt;em&gt;https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/fig3_TCXO.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; &lt;a href="https://www.electronics-notes.com/articles/electronic_components/quartz-crystal-xtal/tcxo-temperature-compensated-crystal-xtal-oscillator.php"&gt;https://www.electronics-notes.com/articles/electronic_components/quartz-crystal-xtal/tcxo-temperature-compensated-crystal-xtal-oscillator.php&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations. ASGTX5DAF1-250.0000, ASGTX5PAF1-156.2500T2, and ASGTX5DAF1-125.0000 are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/fig4_testcircuits.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://abracon.com/datasheets/ASGTX5.pdf"&gt;&lt;em&gt;https://abracon.com/datasheets/ASGTX5.pdf&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;div style="clear:both;"&gt;&lt;/div&gt;
</description></item><item><title>TCXOs for 5G Applications</title><link>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications/revision/1</link><pubDate>Fri, 17 Dec 2021 19:58:22 GMT</pubDate><guid isPermaLink="false">93d5dcb4-84c2-446f-b2cb-99731719e767:87d0fcf6-91d8-4917-9aeb-e5ef4a23a8a2</guid><dc:creator>dychen</dc:creator><comments>https://community.element14.com/learn/learning-center/the-tech-connection/w/documents/27401/tcxos-for-5g-applications#comments</comments><description>Revision 1 posted to Documents by dychen on 12/17/2021 7:58:22 PM&lt;br /&gt;
&lt;p style="border-bottom:1px solid #dadada;font-size:15px;margin-bottom:15px;"&gt;&lt;strong&gt;&lt;a href="#poll"&gt;Take the Poll&lt;/a&gt;&lt;/strong&gt; | &lt;strong&gt;&lt;a href="#discussion"&gt;Join our Discussion&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Synchronizing the 5G Network&lt;/strong&gt;&lt;br /&gt; The 5G (5th Generation) mobile network connects machines and devices at higher data speeds, and with ultra-low latency when compared with its predecessor, 4G. In order to maintain consistent operation and high reliability, network components must be synchronized. Accurate timing (clocking) plays a crucial role in maintaining synchronization within a mobile network. Inaccuracies in synchronization and timing can lead to interference between nodes in a radio access network (RAN). Error-prone oscillators and clocks can cause time shifts that result in deterioration of performance and reliability. This article explores the importance of clocking in network synchronization and the challenges which arise when using oscillators in a 5G network.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;What is an Oscillator?&lt;/strong&gt;&lt;br /&gt; An oscillator is an electronic circuit that uses a crystal to generate a periodic electrical signal with constant frequency, also known as a clock or timing signal. Most digital circuits rely on clock signals in order to synchronize the different components within them. The following section describes how crystal oscillators are used in 5G application devices for network synchronization.&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;How does a crystal generate a clock signal?&lt;/strong&gt;&lt;br /&gt; Certain crystals generate their own electrical signal when mechanically squeezed or pressed. This is called piezoelectricity, a word derived from Greek, where &lt;em&gt;piezein&lt;/em&gt; means to &amp;ldquo;squeeze&amp;rdquo; or &amp;ldquo;press&amp;rdquo;, and &lt;em&gt;piezo&lt;/em&gt; means &amp;ldquo;push&amp;rdquo;. Passing electricity through a piezoelectric material causes them to vibrate, thus generating their own electrical signal of a fixed frequency. Quartz is a widely used piezoelectric material.&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;Clocking and Synchronization in 5G Applications&lt;/strong&gt;&lt;br /&gt; The goal of a radio access networks (RAN) is to optimize service performance and reliability. A RAN is comprised of different commponents that are synchronized, each contributing functionality in order to deliver required services. Timing accuracy and availability are important considerations for the end product, as well as cost.&lt;/p&gt;
&lt;p&gt;Figure 1 shows an open RAN architecture. It consists of a remote radio unit (RRU), fronthaul switch, and a distributed unit (DU). The block diagram shows a crystal oscillator (TCXO and OCXO) generating the clock signal to synchronize these devices. The remote radio unit (RRU) serves as the consumer&amp;#39;s access point to the network. The distributed unit (DU) connects the central unit (CU) and the mobile core. The fronthaul switch routes traffic between the RRU and DU.&amp;nbsp; These components need to be precisely synchronized to avoid data packet loss and system interruptions.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="RAN Network Block Diagram" src="/e14/assets/main/2021/fig1_RAN.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 1: Block diagrams of the role of an oscillator in the RRU and DU systems&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators"&gt;&lt;em&gt;https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;Many 5G networks rely on Time Division Duplexing (TDD), a method of duplex communications where inbound signals are separated from outbound signals based on time allocation in the same frequency band. This requires all devices to be precisely synchronized. This synchronization is typically based on the IEEE 1588 Precision Timing Protocol (PTP). Synchronous Ethernet (SyncE) is another standard that can be used synchronizing frequency. The network architecture dictates whether PTP, SyncE, or both are used for synchronization.&lt;/p&gt;
&lt;p&gt;In PTP, a device called the grandmaster uses a sync source (usually GPS-based) to create several timestamped PTP packets that are delivered to follower clocks at other locations. The packets are used to calculate the time offset between the grandmaster and follower clock, after which a local clock signal can be generated by the follower clock at its own location. PTP is an intelligent system, and is able to adapt to grandmaster loss.&lt;/p&gt;
&lt;p&gt;SyncE is an older system in which a high quality clock reference (usually from a GPS or Cesium clock source) is used to time the output from the core of the network. At other locations on the network, clock recovery takes place, analyzing the signal edges of the output signal and using them to derive their own clock signal for the receiving equipment.&lt;/p&gt;
&lt;p&gt;The DU must pass a precisely synchronized timing signal to the fronthaul switch and the RRU. Clocking in the DU should be resistant to issues such as heat under a heavy load, or the addition of a fan to the system. The RRU needs to be the most environmentally robust, because they are usually placed outdoors, on rooftops and poles, and near roads and highways. Because precise synchronization needs to be maintained between the DU, fronthaul switch, and RRU, jitter cleaners are used to reduce any jitter that might occur due to environmental factors.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Challenges with Oscillators in 5G Applications&lt;/strong&gt;&lt;br /&gt; Environmental stress can have an effect on oscillator performance. An oscillator&amp;#39;s frequency slope describes how the frequency behaves when ambient temperatures vary. High-frequency slopes correspond to sudden frequency changes. Figure 2 compares the frequency over temperature slope of the MEMS-based TCXO and three quartz-based TCXOs. In PTP-dependent applications, a low frequency over temperature slope allows the oscillator to maintain an accurate reference between timing packets, even under a fast temperature ramp.&lt;/p&gt;
&lt;p&gt;5G networks rely on a large density of radios, and as such, radios are often mounted in locations that are subject to vibration from multiple sources, including trucks, trains, cars, wind, and thunder. Oscillators deployed in these radios must maintain stable performance during environmental stress to prevent dropped links.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="MEMS and Quartz oscillators" src="/e14/assets/main/2021/fig2_MEMSQuartz.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 2: Frequency over Temperature Comparison of the MEMS TCXO and three quartz-based TCXOs&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators"&gt;&lt;em&gt;https://www.embeddedcomputing.com/application/networking-5g/5g-oran-timing-challenges-satisfied-by-mems-precision-oscillators&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Types of Clocks (Oscillators)&lt;/strong&gt;&lt;br /&gt; Oscillators are categorized into various types, depending on their working function and structure, including LC resonators, ceramic resonators, crystal oscillators, and the atomic frequency standards like Cesium and Rubidium-based oscillators.&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Crystal Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Crystal oscillators are quartz crystal-based and have self-compensated temperature stability, superior initial accuracy, and are available at moderate cost. They offer excellent stability and can serve a stable clock source for many contemporary connectivity protocols, such as Wi-Fi, Bluetooth, and Zigbee, as well as Ethernet, LIN/CAN, and industrial applications. Crystal oscillators also come in different varieties:&lt;/p&gt;
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&lt;li&gt;&lt;em&gt;Quartz oscillators (XO)&lt;/em&gt; integrate an oscillator die with a quartz crystal. These offer quartz-like accuracy and low noise benefits, but suffer from board trace-induced decreasing variability. It is necessary to use an XO instead of a bare quartz crystal in minimal noise systems. Quartz oscillators deliver the low noise at high frequency operation.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Oven-controlled crystal oscillators (OCXOs)&lt;/em&gt; use a thermostatically controlled oven to maintain a higher-than-room temperature, and thus deliver a stable signal source at a constant temperature. OCXO&amp;#39;s can achieve a high precision of +/-0.1ppm to 0.1ppb or better.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Micro-electro Mechanical Systems (MEMS)&lt;/em&gt; have evolved in parallel to quartz. Miniature silicon-based MEMS oscillators are resistant to shock and vibration. The complexity of MEMS resonators, however, makes them expensive. The durability and size of MEMS oscillators enable them to work well in wearables, wireless charging pads, industrial controls, and other applications.&lt;/li&gt;
&lt;li&gt;&lt;em&gt;Temperature-compensated quartz crystal oscillators (TCXOs)&lt;/em&gt; are crystal oscillators with a temperature-sensitive reactance circuit in their oscillation loop, which is used to compensate for the frequency-temperature characteristics inherent to the crystal unit. Figure 3 shows a block diagram of a TCXO unit. A Voltage Controlled Crystal Oscillator (VCXO) is an important TCXO component that links to a temperature sensing circuit and applies minute correction voltages to the oscillator. TCXOs provide stabilities of 1 part per million (ppm) to 0.1 ppm. A notable advantage of a TCXO is its relatively high stability while consuming minimum power (several milliwatts). These can thus be ideal for multiple communications and telecom applications, such as point-to-point RF, GNSS/GPS, mobile phones, and other precision RF connectivity systems.&lt;/li&gt;
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&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="TCXO Block Diagram" src="/e14/assets/main/2021/fig3_TCXO.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 3: A TCXO Block Diagram&lt;br /&gt; &lt;a href="https://www.electronics-notes.com/articles/electronic_components/quartz-crystal-xtal/tcxo-temperature-compensated-crystal-xtal-oscillator.php"&gt;https://www.electronics-notes.com/articles/electronic_components/quartz-crystal-xtal/tcxo-temperature-compensated-crystal-xtal-oscillator.php&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;Atomic Frequency Standard Oscillators&lt;/strong&gt;&lt;/em&gt;&lt;br /&gt; Certain atoms emit and absorb electromagnetic radiation (EM) at resonance frequencies that can be used to derive a stable timing signal. Common atoms used in atomic clocks are Cesium, Rubidium, and Hydrogen, which have resonance frequencies of 9.2 GHz, 6.8 GHz, and 1.4 GHz, respectively. Because the properties of isolated atoms in free space and at rest do not change with space and time, atomic clocks are stable over time and less affected by changes in the environment.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Abracon TCXO Clocks&lt;/strong&gt;&lt;br /&gt; The Abracon ASGTX5 TCXO series are factory-programmable oscillators that are jitter and stability optimized. They provide stable, high-frequency clocking at a small footprint of 5.0mm x 3.2mm, necessary characteristics for driving a communications infrastructure. Designed for +/-3ppm over a broad -40 &amp;deg;C to 85 &amp;deg;C temperature range, these devices meet the Stratum 4 clocking requirements used in edge networking equipment. They are also capable of improving phase-locked loop (PLL) lock time and performance in broadcast and professional video applications.&lt;/p&gt;
&lt;p&gt;Abracon&amp;rsquo;s TXCO oscillators are factory configurable to output frequencies from 15MHz to 2.1GHz, and support LVPECL, LVDS, HCSL, or CML output logic types with voltage options to 1.8V. Figure 4 shows recommended testing circuits for different output logic types. The enabled output can be configured for any combination of pin 1 or pin 2 and active high or active low functionality. The ASGTX5&amp;#39;s design flexibility is important in applications that require backward compatibility with specific pinout or firmware combinations. ASGTX5DAF1-250.0000, ASGTX5PAF1-156.2500T2, and ASGTX5DAF1-125.0000 are some examples from this series.&lt;/p&gt;
&lt;p&gt;&lt;img loading="lazy" style="max-height:360px;max-width:640px;" alt="ASGTX5 Test Circuits" src="/e14/assets/main/2021/fig4_testcircuits.png" /&gt;&lt;/p&gt;
&lt;p&gt;Figure 4: Abracon ASGTX5 TCXO series Oscillator and Recommended Test Circuit for LVPECL, LVDS, HCSL, and CML logic Output&lt;br /&gt; &lt;em&gt;Image Source: &lt;/em&gt;&lt;a href="https://abracon.com/datasheets/ASGTX5.pdf"&gt;&lt;em&gt;https://abracon.com/datasheets/ASGTX5.pdf&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Summing up: Network Synchronization&lt;/strong&gt;&lt;br /&gt; Effective network synchronization is vital for stable and reliable network performance. Various compelling use cases for 5G, such as IoT and Industrial Automation, require precise timing, and the need for accurate synchronization will continue to grow in the near future. The ASGTX5 TCXO series oscillators from Abracon provide stable clocks at high frequencies in a small footprint, making them well-suited candidates to handle clocking duties for 5G applications.&lt;/p&gt;
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