Tektronix TBS1102C Digital Oscilloscope - Review

Table of contents

RoadTest: Tektronix TBS1102C Digital Oscilloscope

Author: john.porter

Creation date: 23 Jun 2021

Evaluation Type: Test Equipment

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 DSOX1202A, Rigol DS1102E, Siglent SDS1102CML+

What were the biggest problems encountered?: Finicky knobs, stop acquisition does not show last signal, digital decode software not included.

Detailed Review:

Tektronix.

Long ago, when my hair was long (and I had hair), I arrived at my new class. The first thing I noticed in the lab was a Tektronix oscilloscope. This was my first day as an electronic engineering student. It was big and blue with a green CRT screen, 60MHz bandwidth and two channels. The trace would brightly display a graphical representation of voltage over time. I could hardly wait to play with that blue 2213. Things have come a long way since I was that young student…

Enter the new Tektronix TBS1102C !

Technology continues to advance. The TBS1000C series is the latest Tektronix entry-level oscilloscopes, with the TBS1102C positioned to take over as the first oscilloscope many new students will see. I hope they will have the same excitement when first entering their labs!

I did not intend to compare the Tektronix TBS1102C to a vintage 2213A, however I did want to point out one thing that has not changed - the layout of the controls remains mostly consistent between the old and the new. The vertical section for the two channels is on the left, then the horizontal section. Finally, trigger controls are found on the right. For those accustomed to this layout, finding your way around the new TBS1102C is easy and intuitive.

The TBS1102C builds on the success of the previous TBS1102B and TBS1102B-EDU, bringing forward most features along with some additions and one drawback.

Highlights of the TBS1102C include:

• 7” WVGA color display provides a large window, allow for plenty of signal view.

• HelpEverywhere® system provides explanatory descriptions in context with the current menu choices.

• Tutorials provide an informative lesson on oscilloscope history, structure, types, probes, along with detailed information on the TBS1102C.

• Integrated courseware with lab exercises for students, and the ability for autoset, cursors and automatic measurement functions to be disabled (previously available in the TBS1000B – EDU models).

• In addition to edge and pulse width trigger types, an added runt trigger allows the detection of signals that pass one threshold but do not pass a second threshold.

• A drawback of the newer model, the sample rate has been reduced to 1GS/s from the 2GS/s available on the previous TBS1102B model.

• Larger storage memory is provided, 20Kpts vs 2.5Kpts.

• Fanless design – the ‘scope is completely silent and lightweight at 4.36lbs. The power button is on top, cleverly preventing stacked equipment from blocking the top heat vents.

The following chart provides a comparison between the TBS1102C and it’s two Tektronix predecessors. Also in the chart are competitive examples, a Keysight DSOX1102G and Rigol DS1102E. As I move through the evaluation, I will be providing functional comparisons to the Keysight as I just happen to have one handy.

Ok, on to my experience evaluating the Tektronix TBS1102C. Check out my blog here, which provides delivery and unboxing photos, a start-up race between the Tektronix TBS1102C and Keysight DSOX1102G and an introductory video.

Usability and interface

Overall, the TBS1102C is extremely easy and intuitive to operate. The controls are nicely set out with common functions front and center. Menus make sense. Combined with the help system, it is easy to know what to do next and where to go.

Screen

The 7” WVGA screen is clear and crisp, a great feature. I appreciate the full width of the screen available to display waveforms, I would always see more cycles on the Tek screen than the Keysight on the same horizontal setting. The Keysight has the same size screen however dedicates one valuable inch on the right for persistent menus and status - the Tek makes full use of the space. However, the Keysight does have significantly higher waveform update rates (50,000waveforms/s) which may contribute to a display that looks much more smooth and polished. I could not find a rating for the TBS1102C, however the TBS1102B-EDU updates at 100waveforms/s. Regardless, I really don't know what my eyes would register beyond 60waveforms/s.

Menus, buttons and knobs

Predictably, there are many buttons, menus, and knobs on the TBS1102C. One of the most important is the Multipurpose knob, which is used in most menus and is one of three knobs that can also be pressed (the other two are horizontal position and trigger level).

Pressing and holding the Multipurpose knob for several seconds will alternate the adjustment between fine and coarse, or you may need to press quickly to make a selection. I did find the dial slow to respond in some menus, such as the measurement window. Slow menu response is more pronounced when HelpEverywhere® is active as this seems to tax the oscilloscope's processor. This often results in overshooting your selection. Also, when pressing to commit a selection, the knob would often move ever so slightly, and would accidentally select something else. In one case, on reading a warning about erasing the system memory, I decided to abort but still selected Yes instead of No... argh.

By contrast, all nine Keysight selection knobs can be pressed. Errors when pressing a knob still happen but are rare. The DSOX1102G knobs adjust to the user – the faster you turn, the faster the adjustment. This feature makes scrolling through settings easy and quick. Can this be improved on the TBS1102C?

TBS1102C menus are clear and intuitive, with selection buttons lined up on the side of the display showing clearly what choice is to be made by each. Most selections provide an automatic prompt for an ‘undo’ option, allowing a way to back out - a great feature. However, the menus stick to the display, reducing screen real estate for the waveform until cleared. The ‘undo’ menu becomes particularly annoying after a while, as this menu pops up often and needs to be cleared as an extra step. Adding an undo button would save a lot of key presses. The Keysight has the same feature and issue but does not use up extra screen space for displaying the ‘undo’ option and can be ignored.

The function button looks promising however it is underutilized. It only has one function in it’s menu, which toggles between coarse and fine adjustments. This is the same as holding down the Multipurpose knob, so is redundant. I would like to have seen more added here, perhaps including a quick way to display a snapshot of measurements.

Cursors

Using the cursors to conduct measurements can take time though it is not painful. It takes some effort moving between coarse and fine adjustments for each X and Y axis. The cursors do not line up to natural points automatically, nor do they follow the waveform if the scale changes - these cursors are manual.  The exception is when using FFT where the cursors easily 'snap' to the frequency. The Keysight cursors are manual as well, however will track if the scale changes.

Despite the manual setup, the resulting display is one of my favorite features of the TBS1102C! Once you finally have the cursors set, the results are placed intuitively on top of the waveform, showing clearly what each number is representing. It is much easier to interpret than the Keysight where the results are at the bottom and reference X and Y. The Tek display reminds me of hours spent drawing many graphs to look exactly like this – how much easier it would have been with the TBS1102C.

Triggering

Triggering options include the standard variety with Edge and Pulse Width, however the TBS1102C does add Runt detection, a useful feature which allows the user to define a lower threshold and an upper threshold. The ‘scope can trigger if a signal crosses one but not both thresholds – handy. Other standard features are available, such as persistent display and hold off. The Keysight does not have a specific runt detection however it does have more options for triggering, including video, serial, setup and hold, pattern, and rise/fall time.

Measurements

Digital oscilloscopes offer automatic measurements. I really do not miss the days of counting divisions and graduations, and then manually calculating frequency, amplitude, or a variety of other measurements. Do not miss that at all. The TBS1102C provides 32 automatic measurements which can be viewed as a ‘snapshot’ through the measurement menu. It does not take long to access this snapshot, but it is not quick either and would benefit from easier access. ie. a quick access option could be placed under the function menu as I noted earlier.

Additionally, the TBS1102C can display up to six measurements on the main display, selected from the 32 available for either channel, and semi-transparent such that the waveforms behind are still visible. I used this feature often. Measurements can be gated to calculate the full record, only what is displayed, or even between cursors.

The Keysight can only display four custom selected measurements along the bottom of the screen, however it does have a programmable quick action button that can be set to view the ‘snapshot’ of all measurements instantly.

Probes

The Tektronix TBS1102C comes with two passive 100MHz 10x probes whereas the Keysight comes with two passive 200MHz 1/10x probes. Perhaps no surprise to you, however this was the first time I had seen a 10x only probe - where did that little switch go? However, I really can't remember the last time I used a 1x setting, it is unlikely I would miss 1x capability. There are plenty of upgraded probe options available, at extra cost of course.

Probe calibration of the 10x probes is easy, the probe compensation output delivers a 1kHz, ~5vp-p square wave. Probe adjustment is manual using the included tool on the probe, checking to see if the waveform peaks are straight. The Keysight has a probe check function, however if adjustment is needed, it is done in the same manual fashion.

Computer integration

Connectivity and availability of computer software for use with an oscilloscope is an area of specific interest. At this level of oscilloscope, a student or bench user should not be expected to purchase an expensive program only to capture images and data.

The Tektronix TBS1102C is supported by many software packages, including TekScope, Kickstart, Keysight’s BenchVue and more. These are available at additional cost, normally through a regular subscription service. Break out your wallet.

Luckily, the TBS1102C is also supported by Tektronix OpenChoice software which can be downloaded at no cost. OpenChoice offers only basic connectivity though, you can capture a screen, waveform or save the ‘scope’s settings. It is older software and on Windows 10 it can cause high processor utilization or can even crash - I have experienced both. Nevertheless, it is a satisfactory tool and I have used OpenChoice for many of the images in this review.

The Tek TBS1102C does not have any built in digital signal decoding capabilities, so it would rely on one of the more expensive software solutions to analyze and decode data if this is something that you require. It may be possible that free software, such as Sigrok, could decode waveforms saved in .csv format however I did not explore this. The TBS1102C is not directly supported in Sigrok at this time.

By contrast, the Keysight DSOX1102G did not include any computer software and a purchase would be necessary to connect this oscilloscope to a computer in any usable fashion. I believe that Keysight since includes a limited version of BenchVue with new purchases. Luckily, this DSOX1102G has built-in serial decode features, an optional upgrade for that model.

Other items of note

• Autoset on the TBS1102C works great, one press of this button and the waveform is often readily in front of you ready for finer adjustment.

• Math functions provide basic operations between waveforms (+, -, *) and display a calculated waveform.

• Custom labels can be set for each displayed waveform including FFT windows and math waveforms.

• Fast Fourier Transformation (FFT) mathematical calculations have options for Hanning, Rectangular, Hamming and Blackman Harris windows. I am no expert on frequency analysis, however I found the Hanning window easier to understand on the Tektronix's FFT vs. the Keysight's Frequency Response Analysis (Bode plot).

Using the Tek's cursors, I was able to quickly determine there is another signal here at 25kHz.

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• Two reference waveforms can be saved to internal memory, and more to external memory. These can be recalled and displayed along with an active signal.

• Acquisition modes are easy to set up, with sample, peak detect, hi-res or average modes available.

• The record length default is 2kpt, you must change this manually to 20k following a default setup action. Options are 1k, 2k, 20k or Auto. The Keysight DSOX1102G has 1Mpt segmented memory which allows for many more events to be recorded.

• There is no support on the Tek TBS1102C for defining a custom waveform mask. Waveform masks are available with some prepared course material to all a student to compare results within a defined range. By comparison, the Keysight does support custom waveform masks.

• Zoom is implemented well on the Tek and displays the waveform at top and a clear close look at a section of the waveform. Scrolling through waveforms, especially in zoom mode, can take a lot of spins of that Multipurpose button though - even on a coarse setting.

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• Saving images to USB or to the computer is easy. Waveforms and setup information can be saved and readily recalled.

• 1GS/s sample rate, compared to the Keysight’s 2GS/s. For a 100MHz ‘scope, 1GS/s should be reasonable in most cases, however there is a noticeable difference between the two ‘scopes resolution when at full sample rate as shown below.

Tektronix TBS1102C 1GS/s 200mV, 100ns    vs.    Keysight DSOX1102G 2GS/s 200mV, 100nS

Evaluation as an educational tool

Although I am no longer a full-time student, I continue to learn something new every single day and am always seeking out new ideas or concepts. I have also been an instructor in a past life (career). So it was natural for me to keep one eye, often both, examining how the new TBS1102C may support those new to electronics engineering and their instructors.

The TBS1102C did not disappoint! This oscilloscope is at the top of the field for use in educational facilities and for learning oscilloscope concepts.

The Scope Intro provides information on oscilloscope history, structure, types, how to find events and an overview of the TBS1000C series and operation. HelpEverywhere® provides excellent, informative descriptions and diagrams throughout the various menus in the TBS1102C. If you want to chose between Edge or Pulse Width triggering, the descriptions for each are right there as you make the choice in the menu. Sometimes the help screen can get in the way and needs to be cleared, such as when setting cursors.

Integrated courseware provides labs for students with a lab overview and procedure description along with diagrams or pictures. Data collection and lab reports detail the student’s results for each step. This can be saved to USB and sent to the instructor to verify or mark. The courses may even include a reference waveform or waveform mask to aid the lab. Instructors can make their own labs using Tektronix Course Editor software.

I went through several Arduino labs to see how it worked. The lab setup and procedure are intuitive; however, the data collection is challenging, requiring careful attention to the available instructions. While collecting data, I often ended up out of the course to make a measurement which then required me to navigate and find my place in the course again. Ideally a student would have the course procedure available on a computer to view while making measurements - but if this is not available, all can be done within the oscilloscope.

Unfortunately, I was only able to access older labs made for the TBS1102B series. Tektronix had recently upgraded their website and were still in the process of updating the courseware section during my review. When I reached out to technical support, they were responsive and helpful to send copies of archived courseware and Arduino code.

Instructors may want to invest in Tek SmartLab to take advantage of central administration of a lab’s oscilloscopes.

The TBS1102C can lock out features such as cursors, measurements, and autoset. This allows an instructor to force students to perform operations manually. Students would need to resort to old-school methods - counting divisions and using math to calculate frequency and amplitude. While I would not want to inflict this experience on a student, I do understand that there may be some (limited) value to enable students to be familiar with legacy technology and for students to gain an appreciation of the old ways.

With HelpEverywhere®, integrated courseware, and the ability for central administration, the TBS1102C absolutely excels in the educational environment!

Sample use cases – and a bug!

First the bug: I took the TBS1102C through it’s paces by conducting measurements in a few scenarios. In doing so, I found a weird behavior in the TBS1102C that I would hope to see corrected in a later firmware release.

When I stop acquisition by pressing Run/Stop, the screen does not show the last signal as I would expect, instead it pauses the display with whatever was showing when I hit stop. This display may be many, or a combination of signals as I show in the picture. Changing the horizontal or vertical scale one click any direction and back again clears the image and the correct image of the last waveform appears. This behavior is consistent and does not occur on the Keysight.

Sample Use Cases - A few measurements may help showcase the features of the TBS1102C, along with short descriptions.

1) Triggering on a noisy sine wave using noise reject

Utilizing a particularly noisy sine wave, the oscilloscope triggers on the sine wave and triggers on the noise within the sine wave, producing what appears to be two waves as shown in the below picture. Stopping acquisition confirms there is only one (once overcoming the bug noted above).

Setting the coupling to “noise reject” clears the waveform up nicely, with only the single (still noisy) sine wave remaining once acquisition is resumed. This worked perfectly on both ‘scopes.

2) Triggering on a burst of digital pulses using trigger holdoff

A stream of digital pulses provide the input with pauses between each burst. However, the oscilloscope displays a running stream of digital activity. Pressing stop and measuring a burst shows that each is approximately 840us long and less than 1ms.

Setting the holdoff to 900us allows for the trigger to occur on the start of a burst and not trigger again until the next burst. This displays a stable waveform once acquisition is resumed. This worked perfectly on both ‘scopes, although the TBS multipurpose knob was finicky when setting the holdoff times (as I noted earlier).

3) Capturing a glitch using pulse width

Using a clock signal as the input, an infrequent glitch is present in the signal. This causes the waveform to flicker occasionally, the Tek’s default setting has persistence set to on, with a persist time of auto which momentarily shows a glitch. Setting persistence to infinite provides more clarity.

Using cursors shows the glitch has a pulse width less than 4us

I set the trigger type to ‘pulse width’, mode to ‘normal’ and set to trigger on a pulse less than 4us. Now we can clearly see the glitch. This worked perfectly on both ‘scopes.

Mains quality test (Category II)

One of the features of the vintage Tektronix 2213A that has kept it as a fixture on my bench, is that it’s input voltage limit of up to 800Vp-p allows the oscilloscope to be used to test AC power quality. The Keysight has an input voltage limit of 150V RMS. The Tektronix TBS1102C allows an input of up to 300V RMS which supports testing of 120VAC with room for some noise.

WARNING: The following experiment uses dangerous voltage, hazardous for you and for your oscilloscope.

I mentioned I used to be a student and instructor at points during my time. I was also an electrician for several years – I do not fear Mains voltage however I do have a healthy respect for it. Mains voltage in North America is normally around 120VAC RMS, 60Hz and can injure, kill or can blow a ‘scope up in smoke in seconds.

I have not checked the quality of Mains voltage in my house, even though I have lived here for several years. I had installed a Siemens 20A surge protected circuit breaker in our panel to protect all circuits in the house, I do have confidence that it is filtering most spikes from entering the home and filtering much of the noise inside. But what does the AC look like without the surge protected breaker active?

Safely testing Mains with an oscilloscope is a subject of debate on many EE forums. Here is my understanding of the problem using an oscilloscope to measure Mains: your bench oscilloscope is connected to Earth ground. On most ‘scopes, the BNC connector is also connected to Earth ground, as shown below there is minimal resistance between the BNC connector and Earth ground on the green wire. Finally, this connects the probe’s ground clip to Earth ground through the oscilloscope. The hot wire, and sometimes the neutral wire, are not at 0V and neither should not be connected to the ground clip or a possible voltage disagreement may be “resolved” within your ‘scope’s circuitry or probe (aka smoke). Some people float their ‘scope to get around this, however this is an extremely dangerous solution in my opinion.

Further, make sure your oscilloscope and probes are rated for the voltage you are measuring. The voltage is important, but also the Category rating (I, II, III, IV) based on what the DUT is. CAT I equipment should not be used to measure electrical outlet voltage, even CAT II is not sufficient in all cases, such as measuring an outlet near the panel. The TBS1102C and probes are rated at 300V RMS, CAT II which supports my test.

Note: My bench multimeter, an old Fluke 8050A, decided this was a good time to die on me - just as I was setting up. No, it did not blow up!  As a result, I resorted to a backup meter.

My preference and recommendation is to use a differential probe which is made for this application.

In this example I use both a differential probe (Channel 1, yellow) and a direct connection (Channel 2, blue) to compare the two measurements and see how accurate the differential probe is. In both cases I am using building ground as a reference and the neutral is disconnected, however I could have used the neutral wire with the differential probe.

First, I test the voltage with the surge protector active. I also included the legacy Tektronix 2213A in this test for fun. The TBS1102C differential probe (yellow) is set to 50x and channel 1 is also set to 50x.

The waveforms are not perfect rounded sine waves, which did not surprise me. I do like how accurately the differential probe matches the waveform of Channel 2, they are nearly identical with only a slight variance in voltage. Secondly, I test with the surge protector off. No appreciable change, the power must be fairly clean in my neighborhood. While this is a good thing, it did make for an anti-climatic test, and I am not risking trying during a thunderstorm.

Moving forward, even though I was within safety limits, I will simply use a differential probe – it is safest.

Conclusion

The Tektronix TBS1102C is easy to use, extremely easy to learn with, and a powerful oscilloscope for an entry level price.

The TBS1102C provides the trigger and acquisition functions I would look for and a new one for runt detection. Menus are clear and easy to understand. The Oscilloscope introductory guides and HelpEverywhere® system are descriptive and informative – even I was able to learn a thing or two from the help screens.

I requested features for a firmware upgrade or for later models: a) adding a function in the function button’s menu for quick access to the measurement snapshot, b) controls that adapt to the speed of use, and c) adding an undo button in place of the pop up menu.

I noted a bug regarding the way the display shows waveforms when acquisition is stopped. I found the knobs to be finicky. The knobs were slow to respond when the oscilloscope was working hard to display help screens.

Included computer software integration is there. OpenChoice does work for basic capture needs, however does not provide analysis, digital signal decoding nor device control.

Perfect for home labs, however the Tektronix TBS1102C is more expensive than some of the other choices that it competes with directly. The Keysight DSOX1102G is even more expensive, but does come with additional features such as a function generator, 2GS/s and other optional upgrades. Some may need to balance the cost vs. additional features, warranty, and capability when comparing the TBS1102C to other oscilloscopes. The TBS does not have the capability to decode digital signals, which would be ok if software were included to deliver this ability – it is not.

The TBS1102C did everything I asked it to with ease. This 100MHz ‘scope provides a wealth of features for an entry level model. Did I mention it has a five (5) year warranty? A favorite feature is the intuitive on-screen measurements when using cursors.

In the classroom, the TBS1102C will absolutely shine! Students can walk into their first class eager to try that bright blue oscilloscope, much like I first did, but they will have a modern oscilloscope loaded with functionality and guidance that will help them learn quickly and easily. I do like this ‘scope a lot!

That concludes my review of the Tektronix TBS1102C. If you have any questions, or would like more information, please drop me a note. I will be happy to help.

Interested in owning one? You can buy the Tektronix TBS1102C here in the Newark online store.

Gecko Approved !!