https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78en-USTelligent Community 12https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78Wed, 13 Sep 2023 07:24:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:87a64ce8-f645-4bf6-8aa1-70fab1010d88Matthttps://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78#commentsCurrent Revision posted to Documents by Matt on 9/13/2023 7:24:00 AM<br /> <p><span class="TextRun SCXW36725694 BCX0" lang="EN-US" data-contrast="auto"><span class="NormalTextRun SCXW36725694 BCX0">In this episode of Workbench Wednesdays, James dives into the world of oscilloscopes and the Nyquist theorem, shedding light on the often-misunderstood concept of aliasing. He begins by explaining the Nyquist-Shannon theorem, which </span><span class="NormalTextRun SCXW36725694 BCX0">states</span><span class="NormalTextRun SCXW36725694 BCX0"> that to accurately reconstruct a signal, you need to sample it at least twice as fast as its fundamental frequency. However, James points out a crucial detail &ndash; the theorem requires sampling faster than two times the signal frequency, not exactly two times.</span></span><span class="EOP SCXW36725694 BCX0">&nbsp;</span></p> <p><a href="https://youtu.be/UHwyHcvvem0">https://youtu.be/UHwyHcvvem0</a></p> <p><span data-contrast="auto">James demonstrates this with a sine wave example, showing how slight shifts in the sample points can lead to incorrect amplitude in the reconstructed waveform. He then introduces aliasing, where the sample rate is much slower than the signal, resulting in a fake, lower-frequency waveform. This is an important concept for makers and engineers to grasp when working with digital oscilloscopes.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m03s634.png" /></span></p> <p><span data-contrast="auto">Moving on to practical examples, James illustrates how changing the sample rate affects measurements. He shows how a 100 MHz sine wave can appear as 20 MHz on the scope when the sample rate is insufficient, but is accurately represented when the sample rate is increased to 400 Msps. He emphasizes that understanding the sample rate is vital for accurate measurements and troubleshooting.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m15s741.png" /></span></p> <p><span data-contrast="auto">James doesn&#39;t stop at sine waves. He explores more complex shapes, such as square waves, and demonstrates how they can lead to aliasing when the sample rate drops below the Nyquist frequency. He also briefly discusses FFTs on digital oscilloscopes, highlighting limitations in frequency span.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m22s697.png" /></span></p> <p><span data-contrast="auto">To avoid aliasing, James delves into the oscilloscope&#39;s memory depth, explaining how it&#39;s connected to sample rate and time-based settings. He highlights how some oscilloscopes automatically adjust memory depth and sample rate to keep the screen filled. James also points out that interleaved ADCs may alter the sample rate when channels are enabled or disabled, underlining the importance of knowing the sample rate.</span><span>&nbsp;</span></p> <p><span><img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m37s228.png" />&nbsp;</span></p> <p><span data-contrast="auto">In conclusion, James provides practical advice on determining the required sample rate for different signals. He recommends sampling at least 2.5 times faster than the fastest frequency in your signal, with square waves requiring additional considerations. He advises keeping an eye on the sample rate when adjusting the time base, as significant changes can indicate aliasing issues. Finally, he encourages viewers to seek help on the element14 Community for any oscilloscope-related questions and provides a list of his oscilloscope-related videos for further exploration.</span><span>&nbsp;</span></p> <h2 id="mcetoc_1ha2d14480"><span>Bonus Content:</span></h2> <ul> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/27291/what-does-bandwidth-mean-for-oscilloscopes---workbench-wednesdays-47">What does Bandwidth mean for Oscilloscopes? - Workbench Wednesdays 47</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28254/electronics-engineer-reviews-korg-nts-2-oscilloscope-kit---workbench-wednesdays-75">Electronics Engineer Reviews KORG NTS-2 Oscilloscope Kit - Workbench Wednesdays 75</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28272/checking-out-digilent-s-analog-discovery---workbench-wednesdays-76">Workbench Wednesdays 76: Checking Out Digilent&#39;s Analog Discovery</a>&nbsp;</span></li> <li><span>&nbsp;<a id="" href="/products/roadtest/rv/roadtest_reviews/195/picoscope_2204a_-_us_3" data-e14adj="t">PICOSCOPE 2204A - USB Oscilloscope - Review</a>&nbsp;</span></li> <li>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/b/blog/posts/bald-engineer-oscilloscope-videos">Bald Engineer’s Oscilloscope Videos</a>&nbsp;&nbsp;</li> </ul> <h2 id="mcetoc_1ha2dhrov2">Bill of Material:</h2> <table class="e14-product-bom-main"> <tbody> <tr> <th>Product Name</th> <th>Manufacturer</th> <th>Quantity</th> <th><a id="e14-product-link-86f5d" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599,3228047,3703266,2365425,2381344,3289978&nsku=51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017&COM=e14c-noscript&CMP=e14c-noscript&osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_BUY_KIT" 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('86f5d'));" data-farnell="4036599,3228047,3703266,2365425,2381344,3289978" data-newark="51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Kit</a> </th> </tr> <tr> <td>MXO4 - 4 Channel Oscilloscope 200 MHz</td> <td>Rohde &amp; Schwarz</td> <td>1</td> <td><a id="e14-product-link-e3d48" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599&nsku=51AK0016&COM=e14c-noscript&CMP=e14c-noscript&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('e3d48'));" data-farnell="4036599" data-newark="51AK0016" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Bench Oscilloscope - 200 MHz, 1 GSa/s, 14-bit, AFG, DMM</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-c7b10" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3228047&nsku=74AH3013 &COM=e14c-noscript&CMP=e14c-noscript&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('c7b10'));" data-farnell="3228047" data-newark="74AH3013 " data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MP720782 Oscilloscope, 2 Channel, 70 MHz, 250 MSPS, 6 kpts, 5 ns</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-b4d24" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3703266&nsku=25ak2941&COM=e14c-noscript&CMP=e14c-noscript&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('b4d24'));" data-farnell="3703266" data-newark="25ak2941" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>PicoScope 2204A - USB 2 Channel Oscilloscope</td> <td>PicoScope</td> <td>1</td> <td><a id="e14-product-link-d6e7e" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2365425&nsku=18X2829&COM=e14c-noscript&CMP=e14c-noscript&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('d6e7e'));" data-farnell="2365425" data-newark="18X2829" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MDO3014 - 100 MHz 2.5 GSa/p Oscilloscope</td> <td>Tektronix</td> <td>1</td> <td><a id="e14-product-link-5abd3" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2381344&nsku=29X1615&COM=e14c-noscript&CMP=e14c-noscript&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('5abd3'));" data-farnell="2381344" data-newark="29X1615" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Arbitrary Waveform Generator - 2 Channel, 160 MHz</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-cbc2a" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3289978&nsku=74AH3017&COM=e14c-noscript&CMP=e14c-noscript&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('cbc2a'));" data-farnell="3289978" data-newark="74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr class="xs-hide"> <td>&nbsp;</td> <td></td> <td></td> <td></td> </tr> </tbody> </table> <p></p> <div style="background:#ffffff;border:1px solid #dadada;margin:0;padding:14px 16px 16px 18px;vertical-align:top;"> <div style="display:inline-block;float:left;padding:0px 25px 8px 0px;"><a href="/challengesprojects/element14-presents/" data-e14adj="t"><img loading="lazy" alt="element14 presents" src="/e14/assets/legacy/2018/e14PresentsJune818.png" width="180px" /></a></div> <div style="display:inline-block;vertical-align:top;width:70%;"><br /> <p style="margin:0;"><span><a class="jivecontainerTT-hover-container jive-link-community-small" href="/challengesprojects/element14-presents/" data-e14adj="t">element14 Presents</a></span>&nbsp; <strong>|</strong>&nbsp; <a class="jive-link-wiki-small" href="/challenges-projects/element14-presents/vcp-program/w/documents/3704/vcp-biography-james" data-e14adj="t">About James</a>&nbsp;<strong>|</strong>&nbsp; <a class="jivecontainerTT-hover-container jive-link-community-small" style="color:#007fac;font-family:Arial, &#39;Lucida Grande&#39;, sans-serif;" href="/challengesprojects/element14-presents/workbenchwednesdays/" data-e14adj="t">Workbench Wednesdays</a></p> <p style="margin:0;"></p> </div> </div><div style="clear:both;"></div> <div style="font-size: 90%;">Tags: Aliasing in oscilloscopes, Sine wave sampling, sample rate, Engineering insights, aliasing, Digital oscilloscope accuracy, Square wave aliasing, FFT limitations, nyquist frequency, Signal measurement tips, electronics troubleshooting, Oscilloscope memory depth, oscilloscope, Nyquist theorem, Signal reconstruction, Maker community support, Sample rate explanation, Oscilloscope tutorials</div> https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78/revision/4Wed, 27 Sep 2023 07:24:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:87a64ce8-f645-4bf6-8aa1-70fab1010d88Matthttps://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78#commentsRevision 4 posted to Documents by Matt on 9/27/2023 7:24:00 AM<br /> <p><span class="TextRun SCXW36725694 BCX0" lang="EN-US" data-contrast="auto"><span class="NormalTextRun SCXW36725694 BCX0">In this episode of Workbench Wednesdays, James dives into the world of oscilloscopes and the Nyquist theorem, shedding light on the often-misunderstood concept of aliasing. He begins by explaining the Nyquist-Shannon theorem, which </span><span class="NormalTextRun SCXW36725694 BCX0">states</span><span class="NormalTextRun SCXW36725694 BCX0"> that to accurately reconstruct a signal, you need to sample it at least twice as fast as its fundamental frequency. However, James points out a crucial detail &ndash; the theorem requires sampling faster than two times the signal frequency, not exactly two times.</span></span><span class="EOP SCXW36725694 BCX0">&nbsp;</span></p> <p><a href="https://youtu.be/UHwyHcvvem0">https://youtu.be/UHwyHcvvem0</a></p> <p><span data-contrast="auto">James demonstrates this with a sine wave example, showing how slight shifts in the sample points can lead to incorrect amplitude in the reconstructed waveform. He then introduces aliasing, where the sample rate is much slower than the signal, resulting in a fake, lower-frequency waveform. This is an important concept for makers and engineers to grasp when working with digital oscilloscopes.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m03s634.png" /></span></p> <p><span data-contrast="auto">Moving on to practical examples, James illustrates how changing the sample rate affects measurements. He shows how a 100 MHz sine wave can appear as 20 MHz on the scope when the sample rate is insufficient, but is accurately represented when the sample rate is increased to 400 Msps. He emphasizes that understanding the sample rate is vital for accurate measurements and troubleshooting.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m15s741.png" /></span></p> <p><span data-contrast="auto">James doesn&#39;t stop at sine waves. He explores more complex shapes, such as square waves, and demonstrates how they can lead to aliasing when the sample rate drops below the Nyquist frequency. He also briefly discusses FFTs on digital oscilloscopes, highlighting limitations in frequency span.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m22s697.png" /></span></p> <p><span data-contrast="auto">To avoid aliasing, James delves into the oscilloscope&#39;s memory depth, explaining how it&#39;s connected to sample rate and time-based settings. He highlights how some oscilloscopes automatically adjust memory depth and sample rate to keep the screen filled. James also points out that interleaved ADCs may alter the sample rate when channels are enabled or disabled, underlining the importance of knowing the sample rate.</span><span>&nbsp;</span></p> <p><span><img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m37s228.png" />&nbsp;</span></p> <p><span data-contrast="auto">In conclusion, James provides practical advice on determining the required sample rate for different signals. He recommends sampling at least 2.5 times faster than the fastest frequency in your signal, with square waves requiring additional considerations. He advises keeping an eye on the sample rate when adjusting the time base, as significant changes can indicate aliasing issues. Finally, he encourages viewers to seek help on the element14 Community for any oscilloscope-related questions and provides a list of his oscilloscope-related videos for further exploration.</span><span>&nbsp;</span></p> <h2 id="mcetoc_1ha2d14480"><span>Bonus Content:</span></h2> <ul> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/27291/what-does-bandwidth-mean-for-oscilloscopes---workbench-wednesdays-47">What does Bandwidth mean for Oscilloscopes? - Workbench Wednesdays 47</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28254/electronics-engineer-reviews-korg-nts-2-oscilloscope-kit---workbench-wednesdays-75">Electronics Engineer Reviews KORG NTS-2 Oscilloscope Kit - Workbench Wednesdays 75</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28272/checking-out-digilent-s-analog-discovery---workbench-wednesdays-76">Workbench Wednesdays 76: Checking Out Digilent&#39;s Analog Discovery</a>&nbsp;</span></li> <li><span>&nbsp;<a id="" href="/products/roadtest/rv/roadtest_reviews/195/picoscope_2204a_-_us_3" data-e14adj="t">PICOSCOPE 2204A - USB Oscilloscope - Review</a>&nbsp;</span></li> <li>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/b/blog/posts/bald-engineer-oscilloscope-videos">Bald Engineer’s Oscilloscope Videos</a>&nbsp;&nbsp;</li> </ul> <h2 id="mcetoc_1ha2dhrov2">Bill of Material:</h2> <table class="e14-product-bom-main"> <tbody> <tr> <th>Product Name</th> <th>Manufacturer</th> <th>Quantity</th> <th><a id="e14-product-link-58556" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599,3228047,3703266,2365425,2381344,3289978&nsku=51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017&COM=e14c-noscript&CMP=e14c-noscript&osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_BUY_KIT" 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('58556'));" data-farnell="4036599,3228047,3703266,2365425,2381344,3289978" data-newark="51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Kit</a> </th> </tr> <tr> <td>MXO4 - 4 Channel Oscilloscope 200 MHz</td> <td>Rohde &amp; Schwarz</td> <td>1</td> <td><a id="e14-product-link-cfb60" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599&nsku=51AK0016&COM=e14c-noscript&CMP=e14c-noscript&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('cfb60'));" data-farnell="4036599" data-newark="51AK0016" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Bench Oscilloscope - 200 MHz, 1 GSa/s, 14-bit, AFG, DMM</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-f7eac" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3228047&nsku=74AH3013 &COM=e14c-noscript&CMP=e14c-noscript&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('f7eac'));" data-farnell="3228047" data-newark="74AH3013 " data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MP720782 Oscilloscope, 2 Channel, 70 MHz, 250 MSPS, 6 kpts, 5 ns</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-1dcc9" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3703266&nsku=25ak2941&COM=e14c-noscript&CMP=e14c-noscript&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('1dcc9'));" data-farnell="3703266" data-newark="25ak2941" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>PicoScope 2204A - USB 2 Channel Oscilloscope</td> <td>PicoScope</td> <td>1</td> <td><a id="e14-product-link-90ea3" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2365425&nsku=18X2829&COM=e14c-noscript&CMP=e14c-noscript&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('90ea3'));" data-farnell="2365425" data-newark="18X2829" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MDO3014 - 100 MHz 2.5 GSa/p Oscilloscope</td> <td>Tektronix</td> <td>1</td> <td><a id="e14-product-link-36b01" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2381344&nsku=29X1615&COM=e14c-noscript&CMP=e14c-noscript&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('36b01'));" data-farnell="2381344" data-newark="29X1615" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Arbitrary Waveform Generator - 2 Channel, 160 MHz</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-4fa44" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3289978&nsku=74AH3017&COM=e14c-noscript&CMP=e14c-noscript&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('4fa44'));" data-farnell="3289978" data-newark="74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr class="xs-hide"> <td>&nbsp;</td> <td></td> <td></td> <td></td> </tr> </tbody> </table> <p></p> <div style="background:#ffffff;border:1px solid #dadada;margin:0;padding:14px 16px 16px 18px;vertical-align:top;"> <div style="display:inline-block;float:left;padding:0px 25px 8px 0px;"><a href="/challengesprojects/element14-presents/" data-e14adj="t"><img loading="lazy" alt="element14 presents" src="/e14/assets/legacy/2018/e14PresentsJune818.png" width="180px" /></a></div> <div style="display:inline-block;vertical-align:top;width:70%;"><br /> <p style="margin:0;"><span><a class="jivecontainerTT-hover-container jive-link-community-small" href="/challengesprojects/element14-presents/" data-e14adj="t">element14 Presents</a></span>&nbsp; <strong>|</strong>&nbsp; <a class="jive-link-wiki-small" href="/challenges-projects/element14-presents/vcp-program/w/documents/3704/vcp-biography-james" data-e14adj="t">About James</a>&nbsp;<strong>|</strong>&nbsp; <a class="jivecontainerTT-hover-container jive-link-community-small" style="color:#007fac;font-family:Arial, &#39;Lucida Grande&#39;, sans-serif;" href="/challengesprojects/element14-presents/workbenchwednesdays/" data-e14adj="t">Workbench Wednesdays</a></p> <p style="margin:0;"></p> </div> </div><div style="clear:both;"></div> <div style="font-size: 90%;">Tags: Aliasing in oscilloscopes, Sine wave sampling, sample rate, Engineering insights, aliasing, Digital oscilloscope accuracy, Square wave aliasing, FFT limitations, nyquist frequency, Signal measurement tips, electronics troubleshooting, Oscilloscope memory depth, oscilloscope, Nyquist theorem, Signal reconstruction, Maker community support, Sample rate explanation, Oscilloscope tutorials</div> https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78/revision/5Wed, 13 Sep 2023 07:24:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:87a64ce8-f645-4bf6-8aa1-70fab1010d88Matthttps://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78#commentsRevision 5 posted to Documents by Matt on 9/13/2023 7:24:00 AM<br /> <p><span class="TextRun SCXW36725694 BCX0" lang="EN-US" data-contrast="auto"><span class="NormalTextRun SCXW36725694 BCX0">In this episode of Workbench Wednesdays, James dives into the world of oscilloscopes and the Nyquist theorem, shedding light on the often-misunderstood concept of aliasing. He begins by explaining the Nyquist-Shannon theorem, which </span><span class="NormalTextRun SCXW36725694 BCX0">states</span><span class="NormalTextRun SCXW36725694 BCX0"> that to accurately reconstruct a signal, you need to sample it at least twice as fast as its fundamental frequency. However, James points out a crucial detail &ndash; the theorem requires sampling faster than two times the signal frequency, not exactly two times.</span></span><span class="EOP SCXW36725694 BCX0">&nbsp;</span></p> <p><a href="https://youtu.be/UHwyHcvvem0">https://youtu.be/UHwyHcvvem0</a></p> <p><span data-contrast="auto">James demonstrates this with a sine wave example, showing how slight shifts in the sample points can lead to incorrect amplitude in the reconstructed waveform. He then introduces aliasing, where the sample rate is much slower than the signal, resulting in a fake, lower-frequency waveform. This is an important concept for makers and engineers to grasp when working with digital oscilloscopes.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m03s634.png" /></span></p> <p><span data-contrast="auto">Moving on to practical examples, James illustrates how changing the sample rate affects measurements. He shows how a 100 MHz sine wave can appear as 20 MHz on the scope when the sample rate is insufficient, but is accurately represented when the sample rate is increased to 400 Msps. He emphasizes that understanding the sample rate is vital for accurate measurements and troubleshooting.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m15s741.png" /></span></p> <p><span data-contrast="auto">James doesn&#39;t stop at sine waves. He explores more complex shapes, such as square waves, and demonstrates how they can lead to aliasing when the sample rate drops below the Nyquist frequency. He also briefly discusses FFTs on digital oscilloscopes, highlighting limitations in frequency span.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m22s697.png" /></span></p> <p><span data-contrast="auto">To avoid aliasing, James delves into the oscilloscope&#39;s memory depth, explaining how it&#39;s connected to sample rate and time-based settings. He highlights how some oscilloscopes automatically adjust memory depth and sample rate to keep the screen filled. James also points out that interleaved ADCs may alter the sample rate when channels are enabled or disabled, underlining the importance of knowing the sample rate.</span><span>&nbsp;</span></p> <p><span><img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m37s228.png" />&nbsp;</span></p> <p><span data-contrast="auto">In conclusion, James provides practical advice on determining the required sample rate for different signals. He recommends sampling at least 2.5 times faster than the fastest frequency in your signal, with square waves requiring additional considerations. He advises keeping an eye on the sample rate when adjusting the time base, as significant changes can indicate aliasing issues. Finally, he encourages viewers to seek help on the element14 Community for any oscilloscope-related questions and provides a list of his oscilloscope-related videos for further exploration.</span><span>&nbsp;</span></p> <h2 id="mcetoc_1ha2d14480"><span>Bonus Content:</span></h2> <ul> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/27291/what-does-bandwidth-mean-for-oscilloscopes---workbench-wednesdays-47">What does Bandwidth mean for Oscilloscopes? - Workbench Wednesdays 47</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28254/electronics-engineer-reviews-korg-nts-2-oscilloscope-kit---workbench-wednesdays-75">Electronics Engineer Reviews KORG NTS-2 Oscilloscope Kit - Workbench Wednesdays 75</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28272/checking-out-digilent-s-analog-discovery---workbench-wednesdays-76">Workbench Wednesdays 76: Checking Out Digilent&#39;s Analog Discovery</a>&nbsp;</span></li> <li><span>&nbsp;<a id="" href="/products/roadtest/rv/roadtest_reviews/195/picoscope_2204a_-_us_3" data-e14adj="t">PICOSCOPE 2204A - USB Oscilloscope - Review</a>&nbsp;</span></li> <li>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/b/blog/posts/bald-engineer-oscilloscope-videos">Bald Engineer’s Oscilloscope Videos</a>&nbsp;&nbsp;</li> </ul> <h2 id="mcetoc_1ha2dhrov2">Bill of Material:</h2> <table class="e14-product-bom-main"> <tbody> <tr> <th>Product Name</th> <th>Manufacturer</th> <th>Quantity</th> <th><a id="e14-product-link-d71f3" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599,3228047,3703266,2365425,2381344,3289978&nsku=51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017&COM=e14c-noscript&CMP=e14c-noscript&osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_BUY_KIT" 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('d71f3'));" data-farnell="4036599,3228047,3703266,2365425,2381344,3289978" data-newark="51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Kit</a> </th> </tr> <tr> <td>MXO4 - 4 Channel Oscilloscope 200 MHz</td> <td>Rohde &amp; Schwarz</td> <td>1</td> <td><a id="e14-product-link-25b27" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599&nsku=51AK0016&COM=e14c-noscript&CMP=e14c-noscript&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('25b27'));" data-farnell="4036599" data-newark="51AK0016" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Bench Oscilloscope - 200 MHz, 1 GSa/s, 14-bit, AFG, DMM</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-74914" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3228047&nsku=74AH3013 &COM=e14c-noscript&CMP=e14c-noscript&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('74914'));" data-farnell="3228047" data-newark="74AH3013 " data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MP720782 Oscilloscope, 2 Channel, 70 MHz, 250 MSPS, 6 kpts, 5 ns</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-43549" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3703266&nsku=25ak2941&COM=e14c-noscript&CMP=e14c-noscript&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('43549'));" data-farnell="3703266" data-newark="25ak2941" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>PicoScope 2204A - USB 2 Channel Oscilloscope</td> <td>PicoScope</td> <td>1</td> <td><a id="e14-product-link-d0294" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2365425&nsku=18X2829&COM=e14c-noscript&CMP=e14c-noscript&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('d0294'));" data-farnell="2365425" data-newark="18X2829" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MDO3014 - 100 MHz 2.5 GSa/p Oscilloscope</td> <td>Tektronix</td> <td>1</td> <td><a id="e14-product-link-19f84" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2381344&nsku=29X1615&COM=e14c-noscript&CMP=e14c-noscript&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('19f84'));" data-farnell="2381344" data-newark="29X1615" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Arbitrary Waveform Generator - 2 Channel, 160 MHz</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-0e969" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3289978&nsku=74AH3017&COM=e14c-noscript&CMP=e14c-noscript&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('0e969'));" data-farnell="3289978" data-newark="74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr class="xs-hide"> <td>&nbsp;</td> <td></td> <td></td> <td></td> </tr> </tbody> </table> <p></p> <div style="background:#ffffff;border:1px solid #dadada;margin:0;padding:14px 16px 16px 18px;vertical-align:top;"> <div style="display:inline-block;float:left;padding:0px 25px 8px 0px;"><a href="/challengesprojects/element14-presents/" data-e14adj="t"><img loading="lazy" alt="element14 presents" src="/e14/assets/legacy/2018/e14PresentsJune818.png" width="180px" /></a></div> <div style="display:inline-block;vertical-align:top;width:70%;"><br /> <p style="margin:0;"><span><a class="jivecontainerTT-hover-container jive-link-community-small" href="/challengesprojects/element14-presents/" data-e14adj="t">element14 Presents</a></span>&nbsp; <strong>|</strong>&nbsp; <a class="jive-link-wiki-small" href="/challenges-projects/element14-presents/vcp-program/w/documents/3704/vcp-biography-james" data-e14adj="t">About James</a>&nbsp;<strong>|</strong>&nbsp; <a class="jivecontainerTT-hover-container jive-link-community-small" style="color:#007fac;font-family:Arial, &#39;Lucida Grande&#39;, sans-serif;" href="/challengesprojects/element14-presents/workbenchwednesdays/" data-e14adj="t">Workbench Wednesdays</a></p> <p style="margin:0;"></p> </div> </div><div style="clear:both;"></div> <div style="font-size: 90%;">Tags: Aliasing in oscilloscopes, Sine wave sampling, sample rate, Engineering insights, aliasing, Digital oscilloscope accuracy, Square wave aliasing, FFT limitations, nyquist frequency, Signal measurement tips, electronics troubleshooting, Oscilloscope memory depth, oscilloscope, Nyquist theorem, Signal reconstruction, Maker community support, Sample rate explanation, Oscilloscope tutorials</div> https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78/revision/2Mon, 11 Sep 2023 15:28:41 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:87a64ce8-f645-4bf6-8aa1-70fab1010d88tariq.ahmadhttps://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78#commentsRevision 2 posted to Documents by tariq.ahmad on 9/11/2023 3:28:41 PM<br /> <p><span class="TextRun SCXW36725694 BCX0" lang="EN-US" data-contrast="auto"><span class="NormalTextRun SCXW36725694 BCX0">In this episode of Workbench Wednesdays, James dives into the world of oscilloscopes and the Nyquist theorem, shedding light on the often-misunderstood concept of aliasing. He begins by explaining the Nyquist-Shannon theorem, which </span><span class="NormalTextRun SCXW36725694 BCX0">states</span><span class="NormalTextRun SCXW36725694 BCX0"> that to accurately reconstruct a signal, you need to sample it at least twice as fast as its fundamental frequency. However, James points out a crucial detail &ndash; the theorem requires sampling faster than two times the signal frequency, not exactly two times.</span></span><span class="EOP SCXW36725694 BCX0">&nbsp;</span></p> <p><a href="https://youtu.be/UHwyHcvvem0">https://youtu.be/UHwyHcvvem0</a></p> <p><span data-contrast="auto">James demonstrates this with a sine wave example, showing how slight shifts in the sample points can lead to incorrect amplitude in the reconstructed waveform. He then introduces aliasing, where the sample rate is much slower than the signal, resulting in a fake, lower-frequency waveform. This is an important concept for makers and engineers to grasp when working with digital oscilloscopes.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m03s634.png" /></span></p> <p><span data-contrast="auto">Moving on to practical examples, James illustrates how changing the sample rate affects measurements. He shows how a 100 MHz sine wave can appear as 20 MHz on the scope when the sample rate is insufficient, but is accurately represented when the sample rate is increased to 400 Msps. He emphasizes that understanding the sample rate is vital for accurate measurements and troubleshooting.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m15s741.png" /></span></p> <p><span data-contrast="auto">James doesn&#39;t stop at sine waves. He explores more complex shapes, such as square waves, and demonstrates how they can lead to aliasing when the sample rate drops below the Nyquist frequency. He also briefly discusses FFTs on digital oscilloscopes, highlighting limitations in frequency span.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m22s697.png" /></span></p> <p><span data-contrast="auto">To avoid aliasing, James delves into the oscilloscope&#39;s memory depth, explaining how it&#39;s connected to sample rate and time-based settings. He highlights how some oscilloscopes automatically adjust memory depth and sample rate to keep the screen filled. James also points out that interleaved ADCs may alter the sample rate when channels are enabled or disabled, underlining the importance of knowing the sample rate.</span><span>&nbsp;</span></p> <p><span><img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m37s228.png" />&nbsp;</span></p> <p><span data-contrast="auto">In conclusion, James provides practical advice on determining the required sample rate for different signals. He recommends sampling at least 2.5 times faster than the fastest frequency in your signal, with square waves requiring additional considerations. He advises keeping an eye on the sample rate when adjusting the time base, as significant changes can indicate aliasing issues. Finally, he encourages viewers to seek help on the element14 Community for any oscilloscope-related questions and provides a list of his oscilloscope-related videos for further exploration.</span><span>&nbsp;</span></p> <h2 id="mcetoc_1ha2d14480"><span>Bonus Content:</span></h2> <ul> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/27291/what-does-bandwidth-mean-for-oscilloscopes---workbench-wednesdays-47">What does Bandwidth mean for Oscilloscopes? - Workbench Wednesdays 47</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28254/electronics-engineer-reviews-korg-nts-2-oscilloscope-kit---workbench-wednesdays-75">Electronics Engineer Reviews KORG NTS-2 Oscilloscope Kit - Workbench Wednesdays 75</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28272/checking-out-digilent-s-analog-discovery---workbench-wednesdays-76">Workbench Wednesdays 76: Checking Out Digilent&#39;s Analog Discovery</a>&nbsp;</span></li> <li><span>&nbsp;<a id="" href="/products/roadtest/rv/roadtest_reviews/195/picoscope_2204a_-_us_3" data-e14adj="y">PICOSCOPE 2204A - USB Oscilloscope - Review</a>&nbsp;</span></li> <li>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/b/blog/posts/bald-engineer-oscilloscope-videos">Bald Engineer’s Oscilloscope Videos</a>&nbsp;&nbsp;</li> </ul> <h2 id="mcetoc_1ha2dhrov2">Bill of Material:</h2> <table class="e14-product-bom-main"> <tbody> <tr> <th>Product Name</th> <th>Manufacturer</th> <th>Quantity</th> <th><a id="e14-product-link-bebfc" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599,3228047,3703266,2365425,2381344,3289978&nsku=51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017&COM=e14c-noscript&CMP=e14c-noscript&osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_BUY_KIT" 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('bebfc'));" data-farnell="4036599,3228047,3703266,2365425,2381344,3289978" data-newark="51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Kit</a> </th> </tr> <tr> <td>MXO4 - 4 Channel Oscilloscope 200 MHz</td> <td>Rohde &amp; Schwarz</td> <td>1</td> <td><a id="e14-product-link-bf9a5" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599&nsku=51AK0016&COM=e14c-noscript&CMP=e14c-noscript&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('bf9a5'));" data-farnell="4036599" data-newark="51AK0016" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Bench Oscilloscope - 200 MHz, 1 GSa/s, 14-bit, AFG, DMM</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-083b9" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3228047&nsku=74AH3013 &COM=e14c-noscript&CMP=e14c-noscript&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('083b9'));" data-farnell="3228047" data-newark="74AH3013 " data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MP720782 Oscilloscope, 2 Channel, 70 MHz, 250 MSPS, 6 kpts, 5 ns</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-6dd03" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3703266&nsku=25ak2941&COM=e14c-noscript&CMP=e14c-noscript&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('6dd03'));" data-farnell="3703266" data-newark="25ak2941" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>PicoScope 2204A - USB 2 Channel Oscilloscope</td> <td>PicoScope</td> <td>1</td> <td><a id="e14-product-link-d446a" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2365425&nsku=18X2829&COM=e14c-noscript&CMP=e14c-noscript&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('d446a'));" data-farnell="2365425" data-newark="18X2829" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MDO3014 - 100 MHz 2.5 GSa/p Oscilloscope</td> <td>Tektronix</td> <td>1</td> <td><a id="e14-product-link-08b48" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2381344&nsku=29X1615&COM=e14c-noscript&CMP=e14c-noscript&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('08b48'));" data-farnell="2381344" data-newark="29X1615" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Arbitrary Waveform Generator - 2 Channel, 160 MHz</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-54b05" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3289978&nsku=74AH3017&COM=e14c-noscript&CMP=e14c-noscript&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('54b05'));" data-farnell="3289978" data-newark="74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr class="xs-hide"> <td>&nbsp;</td> <td></td> <td></td> <td></td> </tr> </tbody> </table> <p></p> <div style="background:#ffffff;border:1px solid #dadada;margin:0;padding:14px 16px 16px 18px;vertical-align:top;"> <div style="display:inline-block;float:left;padding:0px 25px 8px 0px;"><a href="/challengesprojects/element14-presents/" data-e14adj="y"><img loading="lazy" alt="element14 presents" src="/e14/assets/legacy/2018/e14PresentsJune818.png" width="180px" /></a></div> <div style="display:inline-block;vertical-align:top;width:70%;"><br /> <p style="margin:0;"><span><a class="jivecontainerTT-hover-container jive-link-community-small" href="/challengesprojects/element14-presents/" data-e14adj="y">element14 Presents</a></span>&nbsp; <strong>|</strong>&nbsp; <a class="jive-link-wiki-small" href="/challenges-projects/element14-presents/vcp-program/w/documents/3704/vcp-biography-james" data-e14adj="y">About James</a>&nbsp;<strong>|</strong>&nbsp; <a class="jivecontainerTT-hover-container jive-link-community-small" style="color:#007fac;font-family:Arial, &#39;Lucida Grande&#39;, sans-serif;" href="/challengesprojects/element14-presents/workbenchwednesdays/" data-e14adj="y">Workbench Wednesdays</a></p> <p style="margin:0;"></p> </div> </div><div style="clear:both;"></div> <div style="font-size: 90%;">Tags: Aliasing in oscilloscopes, Sine wave sampling, sample rate, Engineering insights, aliasing, Digital oscilloscope accuracy, Square wave aliasing, FFT limitations, nyquist frequency, Signal measurement tips, electronics troubleshooting, Oscilloscope memory depth, oscilloscope, Nyquist theorem, Signal reconstruction, Maker community support, Sample rate explanation, Oscilloscope tutorials</div> https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78/revision/3Mon, 11 Sep 2023 15:28:41 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:87a64ce8-f645-4bf6-8aa1-70fab1010d88pchanhttps://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78#commentsRevision 3 posted to Documents by pchan on 9/11/2023 3:28:41 PM<br /> <p><span class="TextRun SCXW36725694 BCX0" lang="EN-US" data-contrast="auto"><span class="NormalTextRun SCXW36725694 BCX0">In this episode of Workbench Wednesdays, James dives into the world of oscilloscopes and the Nyquist theorem, shedding light on the often-misunderstood concept of aliasing. He begins by explaining the Nyquist-Shannon theorem, which </span><span class="NormalTextRun SCXW36725694 BCX0">states</span><span class="NormalTextRun SCXW36725694 BCX0"> that to accurately reconstruct a signal, you need to sample it at least twice as fast as its fundamental frequency. However, James points out a crucial detail &ndash; the theorem requires sampling faster than two times the signal frequency, not exactly two times.</span></span><span class="EOP SCXW36725694 BCX0">&nbsp;</span></p> <p><a href="https://youtu.be/UHwyHcvvem0">https://youtu.be/UHwyHcvvem0</a></p> <p><span data-contrast="auto">James demonstrates this with a sine wave example, showing how slight shifts in the sample points can lead to incorrect amplitude in the reconstructed waveform. He then introduces aliasing, where the sample rate is much slower than the signal, resulting in a fake, lower-frequency waveform. This is an important concept for makers and engineers to grasp when working with digital oscilloscopes.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m03s634.png" /></span></p> <p><span data-contrast="auto">Moving on to practical examples, James illustrates how changing the sample rate affects measurements. He shows how a 100 MHz sine wave can appear as 20 MHz on the scope when the sample rate is insufficient, but is accurately represented when the sample rate is increased to 400 Msps. He emphasizes that understanding the sample rate is vital for accurate measurements and troubleshooting.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m15s741.png" /></span></p> <p><span data-contrast="auto">James doesn&#39;t stop at sine waves. He explores more complex shapes, such as square waves, and demonstrates how they can lead to aliasing when the sample rate drops below the Nyquist frequency. He also briefly discusses FFTs on digital oscilloscopes, highlighting limitations in frequency span.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m22s697.png" /></span></p> <p><span data-contrast="auto">To avoid aliasing, James delves into the oscilloscope&#39;s memory depth, explaining how it&#39;s connected to sample rate and time-based settings. He highlights how some oscilloscopes automatically adjust memory depth and sample rate to keep the screen filled. James also points out that interleaved ADCs may alter the sample rate when channels are enabled or disabled, underlining the importance of knowing the sample rate.</span><span>&nbsp;</span></p> <p><span><img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-19/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m37s228.png" />&nbsp;</span></p> <p><span data-contrast="auto">In conclusion, James provides practical advice on determining the required sample rate for different signals. He recommends sampling at least 2.5 times faster than the fastest frequency in your signal, with square waves requiring additional considerations. He advises keeping an eye on the sample rate when adjusting the time base, as significant changes can indicate aliasing issues. Finally, he encourages viewers to seek help on the element14 Community for any oscilloscope-related questions and provides a list of his oscilloscope-related videos for further exploration.</span><span>&nbsp;</span></p> <h2 id="mcetoc_1ha2d14480"><span>Bonus Content:</span></h2> <ul> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/27291/what-does-bandwidth-mean-for-oscilloscopes---workbench-wednesdays-47">What does Bandwidth mean for Oscilloscopes? - Workbench Wednesdays 47</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28254/electronics-engineer-reviews-korg-nts-2-oscilloscope-kit---workbench-wednesdays-75">Electronics Engineer Reviews KORG NTS-2 Oscilloscope Kit - Workbench Wednesdays 75</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28272/checking-out-digilent-s-analog-discovery---workbench-wednesdays-76">Workbench Wednesdays 76: Checking Out Digilent&#39;s Analog Discovery</a>&nbsp;</span></li> <li><span>&nbsp;<a id="" href="/products/roadtest/rv/roadtest_reviews/195/picoscope_2204a_-_us_3" data-e14adj="y">PICOSCOPE 2204A - USB Oscilloscope - Review</a>&nbsp;</span></li> <li>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/b/blog/posts/bald-engineer-oscilloscope-videos">Bald Engineer’s Oscilloscope Videos</a>&nbsp;&nbsp;</li> </ul> <h2 id="mcetoc_1ha2dhrov2">Bill of Material:</h2> <table class="e14-product-bom-main"> <tbody> <tr> <th>Product Name</th> <th>Manufacturer</th> <th>Quantity</th> <th><a id="e14-product-link-6dc8d" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599,3228047,3703266,2365425,2381344,3289978&nsku=51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017&COM=e14c-noscript&CMP=e14c-noscript&osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_BUY_KIT" 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('6dc8d'));" data-farnell="4036599,3228047,3703266,2365425,2381344,3289978" data-newark="51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Kit</a> </th> </tr> <tr> <td>MXO4 - 4 Channel Oscilloscope 200 MHz</td> <td>Rohde &amp; Schwarz</td> <td>1</td> <td><a id="e14-product-link-361fd" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599&nsku=51AK0016&COM=e14c-noscript&CMP=e14c-noscript&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('361fd'));" data-farnell="4036599" data-newark="51AK0016" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Bench Oscilloscope - 200 MHz, 1 GSa/s, 14-bit, AFG, DMM</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-089d8" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3228047&nsku=74AH3013 &COM=e14c-noscript&CMP=e14c-noscript&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('089d8'));" data-farnell="3228047" data-newark="74AH3013 " data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MP720782 Oscilloscope, 2 Channel, 70 MHz, 250 MSPS, 6 kpts, 5 ns</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-8541d" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3703266&nsku=25ak2941&COM=e14c-noscript&CMP=e14c-noscript&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('8541d'));" data-farnell="3703266" data-newark="25ak2941" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>PicoScope 2204A - USB 2 Channel Oscilloscope</td> <td>PicoScope</td> <td>1</td> <td><a id="e14-product-link-5fa55" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2365425&nsku=18X2829&COM=e14c-noscript&CMP=e14c-noscript&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('5fa55'));" data-farnell="2365425" data-newark="18X2829" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MDO3014 - 100 MHz 2.5 GSa/p Oscilloscope</td> <td>Tektronix</td> <td>1</td> <td><a id="e14-product-link-e7b46" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2381344&nsku=29X1615&COM=e14c-noscript&CMP=e14c-noscript&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('e7b46'));" data-farnell="2381344" data-newark="29X1615" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Arbitrary Waveform Generator - 2 Channel, 160 MHz</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-a646c" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3289978&nsku=74AH3017&COM=e14c-noscript&CMP=e14c-noscript&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('a646c'));" data-farnell="3289978" data-newark="74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr class="xs-hide"> <td>&nbsp;</td> <td></td> <td></td> <td></td> </tr> </tbody> </table> <p></p> <div style="background:#ffffff;border:1px solid #dadada;margin:0;padding:14px 16px 16px 18px;vertical-align:top;"> <div style="display:inline-block;float:left;padding:0px 25px 8px 0px;"><a href="/challengesprojects/element14-presents/" data-e14adj="y"><img loading="lazy" alt="element14 presents" src="/e14/assets/legacy/2018/e14PresentsJune818.png" width="180px" /></a></div> <div style="display:inline-block;vertical-align:top;width:70%;"><br /> <p style="margin:0;"><span><a class="jivecontainerTT-hover-container jive-link-community-small" href="/challengesprojects/element14-presents/" data-e14adj="y">element14 Presents</a></span>&nbsp; <strong>|</strong>&nbsp; <a class="jive-link-wiki-small" href="/challenges-projects/element14-presents/vcp-program/w/documents/3704/vcp-biography-james" data-e14adj="y">About James</a>&nbsp;<strong>|</strong>&nbsp; <a class="jivecontainerTT-hover-container jive-link-community-small" style="color:#007fac;font-family:Arial, &#39;Lucida Grande&#39;, sans-serif;" href="/challengesprojects/element14-presents/workbenchwednesdays/" data-e14adj="y">Workbench Wednesdays</a></p> <p style="margin:0;"></p> </div> </div><div style="clear:both;"></div> <div style="font-size: 90%;">Tags: Aliasing in oscilloscopes, Sine wave sampling, sample rate, Engineering insights, aliasing, Digital oscilloscope accuracy, Square wave aliasing, FFT limitations, nyquist frequency, Signal measurement tips, electronics troubleshooting, Oscilloscope memory depth, oscilloscope, Nyquist theorem, Signal reconstruction, Maker community support, Sample rate explanation, Oscilloscope tutorials</div> https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78/revision/1Mon, 11 Sep 2023 15:25:54 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:87a64ce8-f645-4bf6-8aa1-70fab1010d88tariq.ahmadhttps://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28318/how-to-avoid-oscilloscope-aliasing-pitfalls-for-accurate-measurements---workbench-wednesdays-78#commentsRevision 1 posted to Documents by tariq.ahmad on 9/11/2023 3:25:54 PM<br /> <p><span class="TextRun SCXW36725694 BCX0" lang="EN-US" data-contrast="auto"><span class="NormalTextRun SCXW36725694 BCX0">In this episode of Workbench Wednesdays, James dives into the world of oscilloscopes and the Nyquist theorem, shedding light on the often-misunderstood concept of aliasing. He begins by explaining the Nyquist-Shannon theorem, which </span><span class="NormalTextRun SCXW36725694 BCX0">states</span><span class="NormalTextRun SCXW36725694 BCX0"> that to accurately reconstruct a signal, you need to sample it at least twice as fast as its fundamental frequency. However, James points out a crucial detail &ndash; the theorem requires sampling faster than two times the signal frequency, not exactly two times.</span></span><span class="EOP SCXW36725694 BCX0">&nbsp;</span></p> <p><a href="https://youtu.be/UHwyHcvvem0">https://youtu.be/UHwyHcvvem0</a></p> <p><span data-contrast="auto">James demonstrates this with a sine wave example, showing how slight shifts in the sample points can lead to incorrect amplitude in the reconstructed waveform. He then introduces aliasing, where the sample rate is much slower than the signal, resulting in a fake, lower-frequency waveform. This is an important concept for makers and engineers to grasp when working with digital oscilloscopes.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m03s634.png" /></span></p> <p><span data-contrast="auto">Moving on to practical examples, James illustrates how changing the sample rate affects measurements. He shows how a 100 MHz sine wave can appear as 20 MHz on the scope when the sample rate is insufficient, but is accurately represented when the sample rate is increased to 400 Msps. He emphasizes that understanding the sample rate is vital for accurate measurements and troubleshooting.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m15s741.png" /></span></p> <p><span data-contrast="auto">James doesn&#39;t stop at sine waves. He explores more complex shapes, such as square waves, and demonstrates how they can lead to aliasing when the sample rate drops below the Nyquist frequency. He also briefly discusses FFTs on digital oscilloscopes, highlighting limitations in frequency span.</span><span>&nbsp;</span></p> <p><span>&nbsp;<img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m22s697.png" /></span></p> <p><span data-contrast="auto">To avoid aliasing, James delves into the oscilloscope&#39;s memory depth, explaining how it&#39;s connected to sample rate and time-based settings. He highlights how some oscilloscopes automatically adjust memory depth and sample rate to keep the screen filled. James also points out that interleaved ADCs may alter the sample rate when channels are enabled or disabled, underlining the importance of knowing the sample rate.</span><span>&nbsp;</span></p> <p><span><img loading="lazy" alt="image" style="max-height:360px;max-width:640px;" src="/resized-image/__size/1280x720/__key/communityserver-wikis-components-files/00-00-00-04-35/vlcsnap_2D00_2023_2D00_09_2D00_07_2D00_15h28m37s228.png" />&nbsp;</span></p> <p><span data-contrast="auto">In conclusion, James provides practical advice on determining the required sample rate for different signals. He recommends sampling at least 2.5 times faster than the fastest frequency in your signal, with square waves requiring additional considerations. He advises keeping an eye on the sample rate when adjusting the time base, as significant changes can indicate aliasing issues. Finally, he encourages viewers to seek help on the element14 Community for any oscilloscope-related questions and provides a list of his oscilloscope-related videos for further exploration.</span><span>&nbsp;</span></p> <h2 id="mcetoc_1ha2d14480"><span>Bonus Content:</span></h2> <ul> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/27291/what-does-bandwidth-mean-for-oscilloscopes---workbench-wednesdays-47">What does Bandwidth mean for Oscilloscopes? - Workbench Wednesdays 47</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28254/electronics-engineer-reviews-korg-nts-2-oscilloscope-kit---workbench-wednesdays-75">Electronics Engineer Reviews KORG NTS-2 Oscilloscope Kit - Workbench Wednesdays 75</a>&nbsp;</span></li> <li><span>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/w/documents/28272/checking-out-digilent-s-analog-discovery---workbench-wednesdays-76">Workbench Wednesdays 76: Checking Out Digilent&#39;s Analog Discovery</a>&nbsp;</span></li> <li><span>&nbsp;<a id="" href="/products/roadtest/rv/roadtest_reviews/195/picoscope_2204a_-_us_3" data-e14adj="y">PICOSCOPE 2204A - USB Oscilloscope - Review</a>&nbsp;</span></li> <li>&nbsp;<a href="https://community.element14.com/challenges-projects/element14-presents/workbenchwednesdays/b/blog/posts/bald-engineer-oscilloscope-videos">Bald Engineer’s Oscilloscope Videos</a>&nbsp;&nbsp;</li> </ul> <h2 id="mcetoc_1ha2dhrov2">Bill of Material:</h2> <table class="e14-product-bom-main"> <tbody> <tr> <th>Product Name</th> <th>Manufacturer</th> <th>Quantity</th> <th><a id="e14-product-link-88d97" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599,3228047,3703266,2365425,2381344,3289978&nsku=51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017&COM=e14c-noscript&CMP=e14c-noscript&osetc=e14-noscript-tracking-loss" data-at-label="PRODUCT_BUY_KIT" 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('88d97'));" data-farnell="4036599,3228047,3703266,2365425,2381344,3289978" data-newark="51AK0016,74AH3013 ,25ak2941,18X2829,29X1615,74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Kit</a> </th> </tr> <tr> <td>MXO4 - 4 Channel Oscilloscope 200 MHz</td> <td>Rohde &amp; Schwarz</td> <td>1</td> <td><a id="e14-product-link-3874c" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=4036599&nsku=51AK0016&COM=e14c-noscript&CMP=e14c-noscript&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('3874c'));" data-farnell="4036599" data-newark="51AK0016" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Bench Oscilloscope - 200 MHz, 1 GSa/s, 14-bit, AFG, DMM</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-8c853" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3228047&nsku=74AH3013 &COM=e14c-noscript&CMP=e14c-noscript&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('8c853'));" data-farnell="3228047" data-newark="74AH3013 " data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MP720782 Oscilloscope, 2 Channel, 70 MHz, 250 MSPS, 6 kpts, 5 ns</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-f74b8" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3703266&nsku=25ak2941&COM=e14c-noscript&CMP=e14c-noscript&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('f74b8'));" data-farnell="3703266" data-newark="25ak2941" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>PicoScope 2204A - USB 2 Channel Oscilloscope</td> <td>PicoScope</td> <td>1</td> <td><a id="e14-product-link-e0939" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2365425&nsku=18X2829&COM=e14c-noscript&CMP=e14c-noscript&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('e0939'));" data-farnell="2365425" data-newark="18X2829" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>MDO3014 - 100 MHz 2.5 GSa/p Oscilloscope</td> <td>Tektronix</td> <td>1</td> <td><a id="e14-product-link-3864c" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=2381344&nsku=29X1615&COM=e14c-noscript&CMP=e14c-noscript&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('3864c'));" data-farnell="2381344" data-newark="29X1615" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr> <td>Arbitrary Waveform Generator - 2 Channel, 160 MHz</td> <td>Multicomp Pro</td> <td>1</td> <td><a id="e14-product-link-ccb3f" data-at-areainteracted="rte-content" data-at-type="click" data-at-link-type="button" href="https://referral.element14.com/OrderCodeView?fsku=3289978&nsku=74AH3017&COM=e14c-noscript&CMP=e14c-noscript&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('ccb3f'));" data-farnell="3289978" data-newark="74AH3017" data-comoverride="" data-cmpoverride="" data-cpc="" data-avnetemea="" data-avnetema="" data-avnetasia="" >Buy Now</a> </td> </tr> <tr class="xs-hide"> <td>&nbsp;</td> <td></td> <td></td> <td></td> </tr> </tbody> </table><div style="clear:both;"></div> <div style="font-size: 90%;">Tags: Aliasing in oscilloscopes, Sine wave sampling, sample rate, Engineering insights, aliasing, Digital oscilloscope accuracy, Square wave aliasing, FFT limitations, nyquist frequency, Signal measurement tips, electronics troubleshooting, Oscilloscope memory depth, oscilloscope, Nyquist theorem, Signal reconstruction, Maker community support, Sample rate explanation, Oscilloscope tutorials</div>