RoadTest: Tektronix Mixed Domain Oscilloscopes MDO4014-3
Author: Instructorman
Creation date:
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?: Tektronix MSO2024 and Agilent MSOX4034A
What were the biggest problems encountered?: So far the biggest problem has been accidental lock up of the oscilloscope caused by certain combinations of settings in the spectrum analyzer section. I've had to cycle power on the scope more than once to recover functional operation.
Detailed Review:
Hello Element 14 community members!
The instrument I am reviewing in this Road Test is a Tektronix MDO4104-3, a mixed domain (time and frequency) oscilloscope with four 1 GHz analogue channels, 16 digital channels and one 3 GHz RF channel. Tektronix offers oscilloscopes in three ranges, basic, bench, and performance with a variety of bandwidths, input channels, screen sizes and features. The MDO4000 series is in the bench range and is packed with several powerful and useful features not found in entry level or basic oscilloscopes.
To clarify, the instrument I received for this Road Test is an MDO4104-3. The instrument described on the Road Test web site is an MDO4014-3. The difference is in the analogue bandwidth: the 4104-3 has a 1 GHz bandwidth and the 4014-3 has a 100 MHz bandwidth. I have informed Element 14 about the discrepancy and have gone ahead with the review under the assumption the change of model was deliberate and that the other reviewer(s) also received an MDO4104-3.
My history with oscilloscopes is lengthy, reaching back to 1973 when I saved my allowance to purchase a decommissioned rack mount oscilloscope from a local military surplus dealer. Oscilloscope technology has come a very long way since that time.From my perspective there have been at least two major shifts in oscilloscope technology since the 1970's that have significantly enhanced the utility of these instruments. First was the switch from cathode ray tube (CRT) displays to pixel based displays. Pixel based display technology allowed scopes to shrink in depth considerably and it enabled easy overlay of text and cursors, greatly enriching the presentation and examination of waveform data. Second was the switch to digital technology that allowed for automated measurements, storage and scrolling though deep memory records of captured waveforms, analytical math functions, bus decoding, limit and mask testing and most recently, mixed signal and mixed domain measurements.
My plan for the MDO4104-3 review is to provide a staged review as follows:
If I have time and can get it to work before the 30-day evaluation window expires on the application modules I will look at USB decode and mask testing.
I hope to have the first component of my review posted here by the weekend.
If there are other aspects of this instrument that members are curious about, please let me know and if I have the resources and time, I'll do what I can to address your questions.
All the best,
Mark Archibald
March 17, 2013 UPDATE - An Overview of the Tektronix MDO4104-3
As indicated in my review plan, I will provide an overview of the MDO4104-3, based on my use of the instrument over several days. Detailed performance specifications are available on the Tektronix web site. Here I will concentrate on the user experience and what I found to be the stand out features of this oscilloscope.
The first characteristic I noticed about this 'scope was its size. Without doubt there are larger oscilloscopes on the market, but when I placed the MDO4104-3 next to the MSO2024 on my bench, the 4000 stood out. To get a sense of the difference size, take a look at Figure 1. The MDO4104-3 is on the left.
Figure 1 Size comparison of two Tektronix oscilloscopes
Almost half of the face of the MDO4104-3 is set aside for a luxuriously large 10.5" diagonal screen. Screen size is an important specification to consider in modern digital oscilloscopes. As measurement and analytical features are enabled, each with its own text box or icon, clutter can overwhelm the signal space on the screen. Take for example the image in Figure 2 obtained from the MSO2024. This image shows a zoomed view of a digital pulse train on channel 1 with a sine wave on channel 2. Channel 3 and 4 are on, but with no inputs. A few measurements are enabled (rise and fall time on channel 1 and frequency on channel 2) and the cursors are on and measuring amplitude and period on channel 1. There is a fair bit going on within that screen; add another measurement or a digital channel or two and the clutter will overwhelm the signals. The MSO2024 has a 7" diagonal screen.
Figure 2 A busy screen image on a 2000 series oscilloscope
Compare Figure 2 with Figure 3. The same measurement scenario was set up on the MDO4104-3 with its 10.5" diagonal screen. Not only is there less clutter, the MDO41014-3 throws in Mean, Min, Max and Standard Deviation measurements and it calculates dV/dt on the cursor positions. Note that in Figure 2 measurement text boxes encroach on the signal display area, but they do not encroach on the signal area in Figure 3. If enough measurements and signals are activated, even the 10.5" display on the 4000 series will be overwhelmed, but in general, a larger screen is a welcome feature when examining a group of signals.
Figure 3 The same measurement set up on a 4000 oscilloscope
So what is Mixed Domain?
The 2000 Mixed Signal and 4000 series Mixed Domain oscilloscopes both have 4 analog channels and 16 digital channels and both have the very useful Wave Inspector feature. I will be demonstrating the digital logic analyzer and Wave Inspector features in my next instalment. A major feature that sets the MDO instrument apart from all other oscilloscopes is the inclusion of a 3 (or 6) GHz spectrum analyzer. This is not the same as the FFT function found on many digital oscilloscopes. There is a fairly robust dedicated spectrum analyzer woven into the electronics on this instrument. A spectrum analyzer is great in and of itself, but the spectrum analyzer on the MDO4000 is time correlated with the analog and digital channels. This means that you can explore the real time relationship between analog signals, digital signals and an RF signal in two domains. Time and amplitude information is gathered on the analog and digital channels while frequency domain information is gathered simultaneously on the RF channel. When I first saw this feature in action I was truly impressed. After using this feature in the course of doing this review, I remain impressed, but I ran into a few frustrations that make me think there is room for improvement in the user interface on the spectrum analyzer. More on this later.
To quickly illustrate the stand alone (not time correlated with analog or digital signals) capability of the spectrum analyzer, look at Figure 4 and Figure 5. Figure 4 shows a basic amplitude modulated carrier with single frequency sidebands. Figure 5 shows an FM modulated carrier with 200 kHz deviation modulated by a 10 kHz noise signal. The max hold feature is enabled, showing the maximum signal envelope along with a single shot spectrum. Also shown is the Spectrogram feature which provides a strip-chart like record of frequency domain behaviour over time.
Figure 4 Basic AM modulation of a 1 MHz carrier showing upper and lower sidebands
Figure 5 Spectrum of an FM signal with 200 Khz deviation and a 10 kHz noise modulation
These spectrum images were fairly easy to obtain. However, while experimenting with the RF section settings I encountered the error message shown below more than once:
At this point the oscilloscope is semi-locked up. Some functions work, but others are non-responsive. The only remedy I have found is cycling the power and waiting 85 seconds for the instrument to reboot.
There will be more on the mixed domain features in a subsequent installation of my review. The next instalment will cover the logic analyzer and Wave Inspector features. In the next instalment I will be using a PIC based data logger, shown connected to the Tektronix logic probe in Figure 6. This platform generates I2C and RS-232 signals that will help illustrate how the MDO4104-3 can trigger and decode serial data streams.
Stay tuned!
Figure 6 PIC based data logger used to illustrate logic analyzer and Wave Inspector functions
March 24 UPDATE
I have been working on a video demonstration of the MDO4104-3 logic analyzer and bus decode features. It turns out I tend to talk a lot, so I have been spending extra time in the editing phase trying to keep the video to a reasonable length (around 10 minutes). It will be a day or two before the video is ready for upload.
In the meantime, I have an update on the spectrum analyzer. My frustration with frequent "application error" lock ups was mounting. A careful read of the user manual and a visit to the Tektronix FAQ site came up empty. I was about to contact a Tektronix Field Service Engineer when I thought about one more approach I could take with operation of the instrument. The errors always seemed to occur when I changed the Frequency or Span settings during an active acquisition. What if I hit the Run/Stop button to stop acquisition before changing acquisition settings? I gave this approach a try and it drastically reduced the number of application error lock ups - but did not eliminate them. Using this modified operational protocol I have encountered only one lock up v. a dozen or so without this protocol.
With the spectrum analyzer behaving better, I decided to get a portrait of the RF chatter occurring in the 0 Hz to 3 GHz range around my bench. I attached an antenna to the RF input, then gathered all the RF devices I could find and set up the analyzer for Max Hold to capture bursts of RF. The devices that came together for this portrait were:
The result of the activating each of these devices in the vicinity of the antenna on the spectrum analyzer is shown in Figure 7.
Figure 7 RF devices in the 0 to 3 GHz range
I expect that spectrum will only get more crowded as time allows for more gadgets to be invented and inserted into our lives.
Once again, I hope to have a video demo of the logic analyzer and bus decode capabilities uploaded in a few days.
Mark
March 26 UPDATE
My review/demo of the logic analyzer capabilities of the MDO4104-3 is in video clip format. There are three clips in total, two are ready for viewing. The first clip below explains the target system (the PIC based data logger) that is used as a source of I2C and RS232 signals for the MDO410-3 to analyze. This clip also illustrates the use of a USB keyboard to enter signal names into the 'scope.
PART ONE - Target system overview and use of keyboard to label signal names
The second clip illustrates the logic probe and its accessories. I2C and RS232 bus decode features are examined. The importance of selecting appropriate record size is illustrated as is the utility of triggering off of bus decode outputs.
PART TWO - Probe options, bus decode, sample size and timing resolution
The third clip illustrates the ability to trigger off of decoded bus values, use of deep memory records, memory search and event tables. I also editorialise a bit on the price of application modules.
I estimate another two days to finish recording and editing the third clip. Please let me know if these clips are of value.
Mark
March 30 UPDATE
The third video clip on the MDO4104-3 logic analyzer review is now uploaded.
MDO4104-3 logic analyzer review PART THREE
Here is a short editorial clip on the cost of application modules. Although I am addressing the cost of Tektronix application modules in this clip, I think the prices for Agilent upgrade licenses are no bargain either.
Editorial on the cost of application modules
Mixed domain review
I've put together a few video clips and screen shots that illustrate what I have investigated and found regarding the MDO41043's mixed domain capabilities. Two of the clips below show stand alone use of the spectrum analyzer, that is, not correlated to an analog or digital time domain signal captured by the oscilloscope. The third clip illustrates a case where a time domain analog signal is correlated to a frequency domain signal.
Capturing FM stations with a loop antenna
Capturing FRS radio carriers Ch 8 through Ch 14
Here is the example showing the time correlated capability of the MDO4000 series to scroll through an analog record while simultaneously examining the frequency domain version of the analog signal.
April 7, 2013 UPDATE
Well, today the 30-day trial on the application modules installed in the MDO4104-3 expires. Unfortunately most of the advanced functions will stop working. It will be awhile before I purchase the necessary licenses to reactivate the bus decode features that I use most often. Due to the cost of these modules I will only be obtaining the ones that I need on a regular basis. This makes sense: why enable features that are rarely used?
I was able to try the USB bus decode feature on a simulated COM port generated by a FDTI chip (the DS232BL RS232 to USB converter). I was able to set up the scope to decode ASCII messages transmitted over the USB connection to a PC. Mostly what I gained from this experiment was a realization that I need to learn a lot more about USB protocol before the decoded data I saw on the scope makes complete sense to me. No problem, I enjoy the continuous learning opportunities that my work in a high technology field provides.
Two more screen captures obtained from the spectrum analyzer are provided below. The first shows detection of the time signal broadcast from WWV Fort Collins Colorado at 5.000 MHz on a night when conditions were favourable for reception in northern Canada. I was impressed that the analyzer was able to resolve a -97.8 dbm signal out of the grass at -120 dbm using a simple loop antenna.
The second screen capture shows local AM radio stations along with a spectrogram which visually correlates signal intensity across a spectrum over time. This is a nice feature that allows observation of RF signal behaviour over longer time scales.
Preliminary review concluding thoughts
I say preliminary review because I expect to learn more about this richly featured powerhouse of an instrument as I spend more time with it. There well may be future additions to this review. In general the MDO4104-3 is an impressive, capable and useful instrument for anyone doing work in embedded system design or troubleshooting. The integrated spectrum analyzer is especially useful for those doing work involving embedded wireless systems. The 3 GHz range on the RF input covers many modern day wireless protocols and there is a 6 GHz version available for engineers or technologists that need the extra range.
This is a complex and sophisticated instrument that requires advanced user knowledge to use properly. I discovered several subtle interactions linking the frequency and time domain sections that are not well documented in the user manual. For example, time domain measurements can be seriously compromised when working with RF signals in the hundreds of megahertz combined with long sample records. After making the FRS video clip above that shows the wonderful mixed domain capabilities of the scope I discovered aliasing of the analog signal when it was expanded. The scope measured about 30 MHz on a 467 MHz signal. To be fair, a warning message ("Low resolution") appeared when I enabled a frequency measurement, but I would have preferred the message to read "Warning: Aliasing of Time Domain signal", or something like that.
I'm still encountering odd lock ups of the scope, usually when changing settings on the spectrum analyzer. From my perspective firmware should not allow the user to setup a configuration that sends the oscilloscope on a walk through the daisies. Unless the scope I have actually has some bizarre fault, and I doubt that is the case, then I'd recommend this shortcoming be addressed by Tektronix in a future firmware update.
In terms of user interface shortcomings, I have to say that the multipurpose knobs on the 4000 series and on the 2000 and 3000 series of Tektronix instruments are sometimes frustrating. It seems at times the operating system is either too sensitive or not sensitive enough to manipulation of these knobs when selecting items from pop-up menus. This frustration is magnified in the MDO4000 series because there is a numeric keypad built into the device, but it is only active on certain RF configuration settings. Even the USB keyboard input only works on some settings. I'd recommend the user interface be upgraded to allow use of the numeric keypad for ALL user interactions that require a numeric input and that the USB keyboard be available for ALL user interactions that require alphanumeric input.
Overall the frustrations and quirks I've encountered do not diminish in any important way the superb utility and awesome feature set of this very capable instrument. I am still stunned at my good fortune in being selected to Road Test this fine piece of equipment. My thanks go out again to Newark/Element 14 and to Tektronix for the most welcome opportunity to review the MDO4104-3 for the Element 14 community.
I welcome further comments or questions from members about the MDO4104-3. My goal is to provide honest and useful content.
All the best,
Mark
June 20, 2013 update
I have had several months of experience with the MDO4104-3 and thought a brief update would be helpful.
First, since submitting my road test the 'scope has not locked up. Not even once. I have not upgraded the firmware and I am not consciously using it differently, so I'm at a loss to explain why the lock ups have disappeared. My hypothesis is that I've acquired a better "feel" for the operation of the instrument through extensive use and have therefore eliminated bad habits that may have led to the frequent lock ups during the review.
My April 7th update reported the expiration of the 30-day evaluation period for all of the application modules. I had also posted a video lament about the high cost of the application module "chicklets". Because the decode features for embedded serial communication are so fantastic and totally addictive, I had to find a way to recover that functionality without doing collateral damage to my savings account. On a whim I tried searching Ebay for a DPO4EMBD module. I nearly fell over when I found one available from a seller in England at a hobbyist friendly price. For anyone looking on auction sites for 4000 series application modules be aware that the license in these modules can be transferred to the 'scope, rendering the module useless. Be sure to ask the seller to confirm that the license is actually resident in the module before bidding. I did and the module I bought works brilliantly.
Finally, I'd like to report that since posting my review of the MDO4104-3 I have not powered up my Tektronix MSO2024. Not even once. Not because the MSO2024 is a bad instrument. Far from it. I adore my MSO2024, but in light of the awesome capabilities just waiting to be put to use in the MDO4104-3, I've made the difficult decision to let my MSO2024 find a new home where it will serve another electronics geek for many years to come.
BTW, best of luck to the entrants in the MSO2024B road test. I will be reading the reviews with nostalgia and delight as new users discover the many capabilities of this fine oscilloscope.
Mark
