new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004

[2N3055]

Using mask is good but one must be aware that mask works on triggered data. That means that scope is blind rest of the time. So if a glitch occurs outside period when scope is doing acquisition it will be missed.

If scope has certain trigger types, triggering can be used to catch anomalies too. Like runt, window or timeout trigger. I don't know which ones RTB has, but should have some of those. Also zone triggering can be used too, but RTB does not have that.

Why do it with triggering? Because triggering will catch 100% of anomalies trigger is set for. And since RTB has history mode (IIRC) you can have anomalies saved for analysis later. So you not only have "something was wrong" but actual "here is the problem" so you can look at it.

[nctnico]

Mask testing on the RTB2000 should also have history available for failed tests. RTM3004 has several options (including saving a screenshot automatically).

Triggering and mask testing complement eachother. Mask testing is typically used in cases (like production testing) where you have a signal at a certain moment (trigger from waveform generator?) which needs to have a certain (complex) shape at that moment.

[Kean]

Using mask is good but one must be aware that mask works on triggered data. That means that scope is blind rest of the time. So if a glitch occurs outside period when scope is doing acquisition it will be missed.

100% agree, but he mentioned stability in a recapped audio device.  If it was digital signal, I'd definitely suggest using triggers.  For audio signals I'd be surprised if the fault was so short lived.

Setting the trigger level to auto mode and with a reasonably low trigger level would be needed to capture unexpected attenuation or complete dropouts.

[2N3055]

Using mask is good but one must be aware that mask works on triggered data. That means that scope is blind rest of the time. So if a glitch occurs outside period when scope is doing acquisition it will be missed.

100% agree, but he mentioned stability in a recapped audio device.  If it was digital signal, I'd definitely suggest using triggers.  For audio signals I'd be surprised if the fault was so short lived.

Setting the trigger level to auto mode and with a reasonably low trigger level would be needed to capture unexpected attenuation or complete dropouts.

All you said was right. I only wanted to add to it.

In audio device, some kind of flaky connection might create dropouts, for instance.
Those dropouts would be similar to brownouts on power grid.

With use of dropout triggers I successfully can detect dropout of single period in a stable frequency waveform. Or single period amplitude excursion over set level. Despite runt trigger was originally meant for digital runts, it will happily detect anomalies in analog signals too..

So you can detect many different things, many ways. More ways you know, more the betterer.. 

[pdenisowski]

Mask testing on the RTB2000 should also have history available for failed tests. RTM3004 has several options (including saving a screenshot automatically).

As an aside, I did make a short video on mask testing with the RTB2000.  RTB does have numerous options on mask violations (screenshot, etc.)

[pdenisowski]

If scope has certain trigger types, triggering can be used to catch anomalies too. Like runt, window or timeout trigger. I don't know which ones RTB has

And I also made a video that goes through all the trigger types on the RTB

And since RTB has history mode (IIRC) you can have anomalies saved for analysis later. So you not only have "something was wrong" but actual "here is the problem" so you can look at it.

Oh yeah, did one on history mode too

[Sorama]

I don’t know you, yet I like your voice   

When I can’t sleep, I watch a video of you.
Either I fall asleep, or I get up to test something I learned.

[pdenisowski]

I don’t know you, yet I like your voice   

When I can’t sleep, I watch a video of you.
Either I fall asleep, or I get up to test something I learned.

Thanks!  I'm good with either outcome 

[salomonander]

Im not sure i understand the triggering part correctly. I had my rtb connected to the trigger output of my generator via the trigger in bnc. Is that ok? It seemed to work perfect though. I did test it by altering the sinus slightly and it showed the correct amount of failures.

[pdenisowski]

Im not sure i understand the triggering part correctly. I had my rtb connected to the trigger output of my generator via the trigger in bnc. Is that ok? It seemed to work perfect though. I did test it by altering the sinus slightly and it showed the correct amount of failures.

Yes, that's correct   The trigger in on the RTB (and, frankly, on most scopes) allows you to start a waveform acquisition based on some externally provided signal.

If your function generator is simply producing a sine wave, you could also trigger on the waveform itself - an "edge" trigger (i.e. triggering when the voltage crosses some threshold) is by far the most common trigger used on oscilloscopes.

[2N3055]

To make a note all the advanced triggers we mentioned previously are triggers on the waveform, not external trigger.

Advanced triggers actually "measure" some parameters of the signal and trigger only when those parameters are satisfied.

Like with dropout trigger, for instance, where scope is not triggering all (showing stuff on screen to simplify) until signal that you monitor has a dropout (signal drops below certain level) for some time. This trigger will 100% reliably detect any signal disconnections that lasted longer than certain configured time.

So scope is monitoring signal constantly and "pulls the trigger" once it sees something out of spec.

[meteo]

Good day.
I use RTB2004. I need to measure common mode and differential interference in a 230 volt AC network (socket). For measurements I use DP700 in 200:1 mode.

https://www.micsig.com/uploads/QuickGuide-DPseries(100-200MHz)high-voltagedifferentialprobe-2025.06.23_1750850255.pdf

The first probe is between phase and ground. The second probe is between zero and ground. Then I add them mathematically and look at the FFT - this is common mode interference. And if I subtract them and look at the FFT - this is differential interference.

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Could you please answer 2 questions:
1. Is this measurement method correct?
2. The first harmonic is very high, and the noise is at the level of -90 dB and less. What is the maximum sensitivity of the oscilloscope that I can use to avoid damaging the input circuits with the first harmonic level, but at the same time to see very weak common-mode and differential interference in detail?
Thank you very much.

[salomonander]

Hey,
I would like to use the fft analyzer for audio signals. But im having problems getting a proper view. I can set the frequency limits to 0hz-20khz for instance. Perfect. But the. The center frequency does not allow me to go below 10khz. But id like to have 1k as the center of the Frequency plot. Is there any way to change that?

[meteo]

The center frequency does not allow me to go below 10khz. But id like to have 1k as the center of the Frequency plot. Is there any way to change that?

Hi, Try Horizontal scale. Try enabling segmented memory if you have that option.

[meteo]

FFT RTB vs scarlett solo 3rd gen
230 V power socket via a step-down transformer.

[Darkover]

Hi everyone,

Is it possible that our RTB has a huge hardware bug?

A few years ago I found that my RTB had a big offset problem on most of the channels. It was in warranty, so I send it back to Batronik/R&S and they replaced the mainboard.

Now I found that there is the offset problem again! Please look a the picture. All channels are not connected/open. The value of the wrong offset change with different amplification. Only CH2 is okay.



I read that there is an LMH6518 as PGA in front of the ADC. I also read that this circuit has some problem.

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1055675/lmh6518-the-potential-root-causes-of-the-output-offset-drift-issue-in-lg-mode

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1256023/lmh6518-dc-maximum-input-range-datasheet-error-urgent-please-read

https://amplifiers118.rssing.com/chan-14134185/article2720.html

Do you think that R&S has a serious problem with our RTB?

Olaf

[Xyphro]

Does that mean you damage your scope by applying a close to full scale DC for long time? That would be quite shocking. Also for R&S who likely relied on that Datasheet.

Reads like somebody did not do HTOL testing properly on that PGA.

I am just considering buying a new scope and had exactly that one in my mind. What should I buy now? 😭

Even more shocking: the datasheet is still not updated, allthough the issue was confirmed like 4 years ago.

[Hydron]

I had issues with one of the LMH6518s, offset was suddenly larger than spec and made the scope fail self alignment. Replacing the IC fixed it. Note it was just a single channel, 3 sounds unlikely? There was one other poster who had a similar failure though I think?

Edit: also worth noting that the self alignment failure made the offset worse after running it, at least on later firmwares. I thought it was a firmware bug for a while but I did some measurements and it showed the PGA was bad (I think the offset changed suddenly as the PGA changed between high and low gain range or something). It was a while ago so don't remember all the details, maybe search this thread for the part number.

[Martin72]

I am just considering buying a new scope and had exactly that one in my mind. What should I buy now? 😭

In 2017, this was a very interesting, desirable scope, but eight years later, I wouldn't want to buy it anymore.
It still scores points with its 1280*800 display resolution, but that's about it; everything else is rather outdated, especially at these prices.
I would rather go for a Siglent SDS2000X HD or, better still, an SDS3000X HD, or wait and see how expensive the MX03 will be, which is due to be released next month.

[edavid]

I am just considering buying a new scope and had exactly that one in my mind. What should I buy now? 😭

In 2017, this was a very interesting, desirable scope, but eight years later, I wouldn't want to buy it anymore.
It still scores points with its 1280*800 display resolution, but that's about it; everything else is rather outdated, especially at these prices.
I would rather go for a Siglent SDS2000X HD or, better still, an SDS3000X HD, or wait and see how expensive the MX03 will be, which is due to be released next month.

Wouldn't you also consider the Magnova?

[Xyphro]

Actually I would consider a Magnovia, but only if I could try it risk free for a month or so at home. From playing at a booth for a few minutes does not give you the same experience as using it really in lab and the investment is for hobby money to big for risks. In Siglent I have brand wise not such a big trust yet after some issues I had with other Siglent equipment.

I thought about the R&S frontend IC issue. I think the only cost neutral way for them is creating a working (manual?) offset calibration for the RTBs. With the downside of gradually eating up dynamic range over time of the scopes of course. Likely other brand products do similar things and just nobody notices.

[tautech]

........
 In Siglent I have brand wise not such a big trust yet after some issues I had with other Siglent equipment.

Please share your story and disclose your supplier.

[Darkover]

I had issues with one of the LMH6518s, offset was suddenly larger than spec and made the scope fail self alignment. Replacing the IC fixed it. Note it was just a single channel, 3 sounds unlikely? There was one other poster who had a

Yes, that is strange. But I thought about it and I think I know the reason now.

In most cases I only use two channels. Channel 3/4 are rarely used. But when I use them, I use them often for current measurement. I have a few (selfmade) potential free current probes (DC to 1Mhz). The output of the probe is an OPV+50R with 3.3V power supply and the scope has to measure 0 to 2.5V. This means for my measurement 0 to 25mA. So the scope has to measure 2.5V at max. Nothing special with it isn't?

But there is an important difference! An example is to measure the current consumption of a microcontroller. Than I move the GND-Line to the bottom of the screen and if the microcontroller draws 20mA, most of the time the voltage is arround 2 to 2.5V. So I use the full screen for 0 to 2.5V! And if I am do programming or don't switch anything of at lunch, it means I have probably a max DC Voltage of 1V or close to that at the PGA for hours. And this is what TI said is bad for the LMH6518.
That means you can not measure full screen DC signal on the scope. And probably other scope with the LMH6518!

I have an idea how to check. If I measure a voltage of -2.5V for an hour, it is possible the offset will be better because it destroy the lower half in the LMH6518. But it is now only an idea. I will check it at the weekend.

If I am right it means we can not use the scope to measure full screen DC signal. That is a shame for any scope and especialy for something so expensive! So I wrote a letter to Batronik/R&S and ask them for repairing, because I think it is there (or TIs!) fault and not my one. I should be in warranty of 2days from my last repair, but I have to talk with my lawyer about it.

I they not will repair it, I can probably exchange the LMH6518 by myself, but this opens the question how can I calibrate the offset in the scope with the new LMH?

And even if anything is working again, it is a shame to have a scope that is not usable for full screen DC signal!

I have never opend the RTB until now, but probably the LMH6518 needs a heatsink? I mean it draws arround 1W!

Oh.. and there arise another question. What happens with there new and shiny RTB2? The same hardware with the same problem?
Or did they noticed it, changed the hardware and forget to tell us about the huge problems with the RTB2004? The answer
for this is important to think about buying anything from R&S in the future or not!

BTW: Did TI inform there customer about the problem in the LHM6518?

Olaf

[Xyphro]

Seems not, the datasheet is still from 2008 so not updated. It MIGHT be that they fixed the part in silence and new revisions don't show that anymore.

Would be good to ask on e2e referencing those 2 links :-)

[Darkover]

> Would be good to ask on e2e referencing those 2 links :-)

Nice idea. I opened the question there, too. :-D

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1569255/lmh6518-offset-problem-with-lmh6518

Olaf