Tektronix MDO3054 Oscilloscope - Review

Table of contents

RoadTest: Tektronix MDO3054 Oscilloscope

Author: tekmeister

Creation date: 22 Aug 2014

Evaluation Type: Independent Products

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: Keysight (Agilent) MSO-X 3000 series, Tektronix MSO3000 series, Tektronix MDO4000 series

What were the biggest problems encountered?: Some freezes of the UI can occur during spectrum analyser mode.

Detailed Review:

Introduction

Writing a review for the MDO3054 is a mammoth task. It's not easy to cover all the features while making sure the review is still a compelling read (and shorter than the complete works of William Shakespeare).

What I've done is attempt to distil my experiences and opinions of the unit, focusing on the best and worst aspects. The review was conducted using firmware version 1.10.

I would like to express thanks to Element14 and Tektronix for the opportunity to review this unit.

Setting the scene

My history with Tektronix dates back to university days, where we used some of the TDS series in the labs. At my first job after graduating, I used a Tek THS720. At the next company, I again used Tektronix. For many years, my main work oscilloscope was a trusty TDS2024B, although I also had access to a DPO7054 later on. It would be fair to say as my career has developed, so has my experience with Tektronix and my appreciation of quality test equipment.

The times too are evolving. Technology continues to advance at a rapid pace, and the embedded systems I work on are becoming increasingly complex. In many cases "wired" has become "wireless". With today's microcontrollers operating at speeds of up to 200 MHz and microprocessors running often in excess of 1 GHz, it's vital that test equipment keeps up.

Fast forward to 2014 and I am working for a small start-up. The project is complex, involving proprietary RF protocols, ARM microprocessors, multiple ARM Cortex microcontrollers, Bluetooth Low Energy (Smart), serial interfaces, audio, wireless charging. There are a lot of components that need to work in tandem.

There is a bare minimum of test equipment. Between almost a dozen electronic and software engineers, the company has a couple of Rigol DS1052E oscilloscopes, a waveform generator, and a Hioki multimeter. There are a couple of additional cheap house-brand multimeters, but these can really only be relied upon for continuity or rudimentary measurements.

Needless to say this equipment is insufficient for our needs. The Rigol scope, for example, lacks any sort of deep memory or serial decoding and the triggering in general is poor. Many of the engineers (myself included) have resorted to bringing some of our own personal gear in.

In this environment, the arrival of a MDO3054 is literally a game-changer. I can think of previous scenarios where the unit would have been useful. For instance, one of the engineers spent quite some time trying to determine why a particular unit was unable to receive RF transmissions. It turned out the reference crystal was not accurate enough, meaning our RF centre frequency was out. The frequency counter and spectrum analyser functions of the MDO3054 could have enabled the root cause to be discovered earlier, saving time (and hence money).

Competition

Ask an electronics engineer who the top two oscilloscope brands are, and he'll no doubt tell you Tektronix and Agilent (now Keysight). These two brands along with many other smaller players are competing for the hearts, minds and wallets of engineers around the world.

I've watched over the years as features were introduced in one brand, later to appear in another brand and often under a different name. First came the digital scopes, then the mixed-signal and the deep memory. Trademarked features such as "Megazoom" and "Wave Inspector" have been introduced to try to woo new customers.

The trend of late with regards to oscilloscopes is to try to integrate as much functionality as possible into a single unit. As well as providing cost benefits - both to the manufacturer and the end-user - when compared with buying separate test gear, it also has the advantage of taking up less space. I can't speak for other engineers, but I'm often running out of desk space.

It's exciting to watch the world's top oscilloscope manufacturers duke it out. Agilent have been leading the charge for the last few years with their "5 instruments in one" X-series oscilloscopes, and I have been waiting to see how Tektronix would respond. Healthy competition is a good thing. The engineers will win in the long run, as costs are driven down and features are  increased.

Specs

The MDO3000 family is the latest from Tektronix, released only 6 months ago. It's a baby sibling to the MDO4000 series which was introduced in 2011. A wide range of models are available, from the 2-channel MDO3012 at 100 MHz (RRP US$3350) to the 4-channel MDO3104 at 1GHz (RRP US$13,900). These prices will scare off the hobbyist, but that's not the target market. This is a scope aimed at professionals.

The MDO3000 series is promoted as being "6-in-1". The MD in MDO stands for "mixed-domain", alluding to the fact that unlike traditional oscilloscopes, this one includes an RF input for spectrum analyser capabilities. Besides the oscilloscope and spectrum analyser, the MDO3000 can also be a digital voltmeter, waveform generator, logic analyser and protocol analyser.

Only the oscilloscope and a bandwidth-limited spectrum analyser come standard, and the DVM add-on is available for free after registering. The other options need to be purchased. [NOTE: Tektronix is running a limited time promotion for additional FREE options!]

What sets the MDO3000 series apart is its (almost) infinite upgradability. You can start with a basic 100 MHz unit with oscilloscope-only functionality and buy add-ons until you have a 1 GHz all-singing all-dancing 6-in-1 model. Upgrades to 500MHz and below are software-only, upgrades to 1GHz require the unit to be sent in for a board change. The only thing that you can't upgrade is the number of channels.

For this road-test, I received an MDO3054 with 500 MHz bandwidth and 4 analogue channels. The options for the 3GHz spectrum analyser, 16-channel logic analyser, and arbitrary waveform generator were preinstalled.

Oscilloscope

First and foremost,  you'll be wanting this unit for its capabilities as an oscilloscope. Tektronix have been producing dependable scopes for a long time and I expected the MDO3054 to have the same great performance. From my point of view it doesn't disappoint.

The Wave Inspector really shines. It gives you a smaller macro view which you can zoom and pan on for the main display.

This in itself is useful, but there's more. It also offers the ability to scan the entire record length for certain events (e.g. edges, runt pulses, or logic values) and will mark these events for you. It's one of those features that once you get used to, you'll never want to let go of.

You can define a label for each channel, using a list of pre-sets or by defining your own. A USB keyboard can be plugged in to the scope to assist with entering text.

The TPP0500B scope probes are the best I've seen, offering a low 3.9pF input capacitance. They feel sturdy and come with both spring and rigid tips. The MDO3054 supports TekVPI: if the connected probes are also TekVPI, the scope will detect the model of probe and automatically adjust for skew, impedance and other parameters.

Logic analyser

The review unit included the add-on for 16 digital inputs. The digital probes are heavy duty (although the cabling is not as nice as the Agilent equivalent) and give you the option of attaching to your board via a 2x8 standard 0.1" pitch header or a set of flying leads. As with the analogue inputs, the digital channels can be labelled. Wave inspector can also be used on the digital channels to search for and mark events or zoom into an area of interest.

Multiple inputs can be grouped together as a bus, which shows up as a separate trace. You can choose whether to display the individual digital channels at the same time as the bus or not. Each input in the bus can be assigned a different voltage threshold.

Arbitrary function generator

A waveform generator is a natural accompaniment to an oscilloscope. Quite often you want to generate an input signal, be it a clock or analogue DC value, and then probe the output.

Configuring basic functions is dead simple. You first select a waveform type, and then enter the frequency/period, offset, amplitude using the multipurpose knobs or the numeric keypad. You can choose to add noise to your output waveform.

The MDO3054 datasheet lists a maximum frequency of 50MHz (without conditions), but in reality there are rather different limits depending on the type of waveform. The MDO3054 will happily generate a 50MHz sine wave, but only a 25 MHz square wave whereas I could only get the ramp function as high as 500kHz.

To get the most out of the function generator, you'll need ArbExpress (a free download from the Tektronix website). This is the same application used with the Tektronix AWG and AFG standalone waveform generators. New waveforms are generated by entering equations or by simply drawing them, before transferring them to the scope. While it is theoretically possible to edit arbitrary waveforms directly on the scope, in practice it's a very long and slow process. Each waveform point needs to be manually set.

I found the ArbExpress application underwhelming. While the functionality is mostly available, the interface is clunky and it looks dated.

The AFG is able to load waveforms directly from the analogue or digital input channels or the stored reference waveforms. This means you can essentially record your waveforms and then play them back. A sync pulse can be sent out the rear AUX OUT connector to allow you to sync with the AFG output.

DVM

The DVM functionality is a free add-on, but does not come installed on the scope out of the box - you'll have to register your unit on the Tektronix website first to receive a licence key. After entering the key, a new DVM option will appear under the Measure menu.

Essentially the DVM is a measurement displayed with larger text. You can select a channel, and view the AC/DC voltage or the frequency. When the DVM display style is set to minimised, it looks just the same as a normal measurement.

Voltage measurements are 4-digit, frequency is 5-digit, so it's good but not great. It's handy just if you need to read the measurement from a greater distance but it's not really an "instrument" in itself. Most of the time you'll probably want it switched off so you can use the top of the display for something else.

Protocol analyser

Serial decoding support is available for a number of protocols from the common SPI, I2C, RS232 to some which I have never used (e.g. FlexRay, MIL-STD-1553). Each set of serial protocols is offered as a separate module upgrade. The good news is Tektronix offers a 30-day trial of all options - the bad news is the trial period starts as soon as the scope is first turned on. I would prefer Tektronix to allow users to explicitly start the trial when they want.

Serial decoding can be done using any of the channels (analogue or digital). Two different buses can be decoded simultaneously.

It's easy to set up - you press one of the bus buttons, change the bus type, and then select which input channels to use. Various parameters are available depending on the protocol.

The bus waveform is displayed as a separate trace but you can also view the individual channels at the same time. It's possible to view the decoded packets in a table, or to save the (time-stamped) data to a file. Once you've set up your bus, you can then use it as a trigger source, e.g. to trigger on I2C start or USB reset.

There's been discussion before as to whether I2C addresses are "7-bit + R/W" or "8-bit including R/W". I'm happy to report that the MDO3054 supports both forms of display, as well as 10-bit addressing.

Spectrum analyser

Pressing the RF button switches the MDO3054 into a view of the frequency spectrum seen at the RF input.

The spectrum analyser is normally limited to the bandwidth of the oscilloscope (i.e. 0-500MHz for a 500MHz scope). With the MDO3SA upgrade, this bandwidth is expanded to a full 3 GHz. This greatly increases the applications, as it extends the reach to cover the widely used ~900MHz and 2.4GHz bands.

The only RF-related accessory the MDO3054 ships with is a N-to-BNC adaptor. In order to make any use of the spectrum analyser, you'll need to invest in some additional RF gear. This might entail some stub antennas to pick up A set of EM sniffer probes will allow you to perform some preliminary EMI work before submitting your products for formal testing.

The interface to the RF display is great. The keypad makes it quick to dial in new settings, and there's an option to turn on automatic markers which provides an view of where the frequency peaks are.

Another very useful feature is the spectrogram. It displays a heat chart showing the frequency spectrum response over time. Hit the Run/Stop key, and then you can scroll back in time to see previous frames. This is excellent for measuring duty cycles of RF transmissions or to find unused frequencies.

The biggest limitation is the lack of ability to use the spectrum analyser at the same time as the oscilloscope. This means you can't correlate the frequency response with what's happening in the time domain. I believe this feature is supported on the Tektronix MDO4000 series, but on the MDO3000 units the oscilloscope and spectrum analyser must be sharing the same ADC.

Often while playing with the spectrum analyser I encountered momentary UI freezes. The unit allows you to manually adjust the resolution bandwidth in order to see more detail in the frequency plot. Set it too low and the MDO3054 becomes notably sluggish. I'm not sure why the option of a Span:RBW ratio of 200000:1 is even available, as the unit doesn't seem to store more than about ~1000 points from each capture. A little more polish is needed in the firmware to improve performance in this area.

Display and controls

One of the greatest changes to oscilloscopes in modern times was the introduction of larger display resolutions.  For years oscilloscope users had to persevere with blocky 320x240 displays. Not so on the MDO3054, the screen is 9" diagonal with a resolution of 800x480. It's a real treat, although the viewing angle could be better. The screen brightness is more than adequate for an office environment but struggles under bright sunlight.

One thing I noticed straight away is the display doesn't actually fill the whole of the opening in the plastic. On my unit there are black bars about 4mm high on both the top and bottom. My guess is Tektronix are using a different display than the one originally designed in. None of the promo shots I've seen have these gaps between the display and the enclosure.

The oscilloscope channel, horizontal and trigger knobs are in fairly familiar places, particularly for those who have used the Tektronix DPO3000. On the far right are the buttons for configuring the spectrum analyser. There is also a dedicated numeric keypad, which is brilliant when setting numeric parameters, especially for the spectrum analyser and waveform generator.

Settings and modes are controlled using the soft keys along the bottom and right-hand sides of the display, and also the multi-purpose knobs A and B. One side-effect of having so many options is sometimes it can take a few presses to get to the setting you want to change. The general pattern is to press a named button to open the soft-menu, then press one of the bottom soft-keys to choose the parameter, then use the right soft-keys or the multipurpose knobs to change the value.

The MDO3054 remembers what I was last doing when I turned it off. When the unit is powered back up, it starts right back where I left it.

Add-ons

Some of the upgrades (scope bandwidth, spectrum analyser bandwidth, DVM) are enabled by entering licence keys and are for a specific unit only (i.e. not transferable). Other options are enabled by inserting little modules into the side of the unit. Tektronix included a couple of expansion modules in the shipment so I was able to test the upgrade process. These are physical modules which unlock additional functionality - in my case I received the MDO3PWR and MDO3EMBD.

Enabling the upgrade is easy as inserting the module (while the power is off!). The licence lives on the modules themselves, so a single module can be shared among multiple scopes in the MDO3000 family. It is also possible to transfer the licence permanently from the module to the scope (and back again).

It's worth noting that the options are nicely integrated to the oscilloscope. For example, with the MDO3EMBD module inserted, additional menu options for I2C and SPI are displayed in the bus decoding and trigger menus.

When the scope is first powered on, all upgrades and options are available for the first 30 days as a trial period.

Miscellaneous

There are many other features that I haven't even touched on. Would you like to receive an email notification and/or automatically save a screenshot when a trigger event occurs? Yup, you can do that.

How about saving a reference frequency waveform from the spectrum analyser and then adding or subtracting it from the live RF waveform? That's also possible.

There's a snapshot function which displays a plethora of measurements in a single table. In fact, the automatic measurements still work even when the channels are turned off!

Connectivity

VGA, LAN and USB ports are available on the back panel. A host USB port is also on the front panel, making it easy to plug in a USB flash drive to store waveforms. Tektronix provides an IVI driver and a VISA implementation (TekVisa), making the scope programmable from a PC. A free application called OpenChoice Desktop is also available - this allows you to connect to the device over USB or LAN and capture the display to an image or save waveform data.

Over LAN, you can directly connect to the oscilloscope from a web browser. Being able to view the display remotely is fantastic. Remote control of the unit is possible but although all the functionality seems to be present I find the interface a bit difficult. Perhaps I'm old-fashioned but when it comes to scopes, give me physical knobs and buttons any day.

Conclusion

The MDO3054 belongs to the Tektronix mid-range family of oscilloscopes, but there's nothing mid-range about this unit. Unless you're working on specialist applications, you aren't going to need anything better. Make no mistake, this is a serious scope for serious users.

The oscilloscope controls are natural and familiar to those coming from older Tektronix scopes (or across from Agilent). The Wave Inspector helps to navigate long acquisitions and find important events. The spectrum analyser when expanded to a 3 GHz bandwidth is powerful. This scope has something for everyone.

The ability to upgrade the unit as your requirements increase (or budget permits!) also provides additional peace of mind. If you're considering getting one of these units, make sure you purchase the 4-channel model as the number of channels is the only thing you can't upgrade later.

That's not to say the unit is perfect. The viewing angle of the screen could have been better and I'm hoping some of the performance issues are resolved in a future firmware update. In addition some of the PC software is a bit cumbersome. I also would've liked to have seen Tektronix offer a 5-year warranty as standard.

Tektronix have taken the MSO3000 series, managed to fit in a spectrum analyser and waveform generator, and still maintained the same price point. I'm not aware of any other units that even come close - the Agilent MSOX-3000 series is about the same price range but lacks the spectrum analyser capabilities (plus the LAN/VGA interfaces are optional extras).

What makes the MDO3000 series even more attractive is the current promotion from Tektronix (ends September 26th 2014). It offers the spectrum analyser upgrade to a full 3GHz bandwidth as well as a protocol decode option for free. This is a fantastic offer and makes the spectrum analyser much more useful.

All in all, the MDO3054 is highly recommended. I think Tektronix are hitting a sweet spot with their MDO3000 series, delivering on both price and features.

Thanks for reading. I'm always looking for ways to improve my reviews so if you have any comments or questions, please leave them below.