As I recall, the issues jacekowski was having most likely come down to incorrect termination of the signal going into the scope. In the pictures jacekowski posted above, there is no information provided about how the signal was terminated. However, if I recall correctly, the signal was split from a single sig gen output and terminated into two (2) 50 ohm bnc through termination connectors at two of the input channels to the scope. I suspect this can cause transmission line problems. You have a 50 ohm transmission line, split, being terminated with two 50 ohm through terminations, and my guess is this explains the effects shown in the photos -- the affects of the signal reflections seem pretty clear to see in the photos. I was able to reproduce exactly this effect with an RTB2004, using a similar setup.
The other thing that I believe occurs with this setup is that as you dial through various frequencies from the sig gen, the amplitude of the signal will become significantly dependent on frequency, and will change as the frequencies change.
It was shown in a photo I provided that the RTB2004 demonstrated exactly the same artifacts -- again -- in all likelihood due to transmission line effects.
However, when terminated properly, these issues almost completely disappear -- with each scope (RTB/MSO).
With proper termination, when a single-shot sweep is performed, the amplitude variations/reflection artifacts pretty much go away and the only remaining artifacts are slight variations in how the sample points are laid down within the instrument's noise envelope that surrounds the signal. Both the RTB and MSO demonstrate this issue, as does any scope out there. In fact, I was surprised at how well the Rigol compared to the R&S in this case. It's clear that the "noise envelope" around the signal on the MSO is "thicker" than the RTB, but for most use cases (in my experience) this just doesn't make that much difference. Having to choose, I'd rather have a much higher waveform refresh rate rather than the tighter noise specs. It just feels like the Rigol reveals more information about the signal, for most general use cases. Don't have a Siglent scope lying around to add to the comparison, so the RTB example is just for limited comparison purposes.
As far as I can tell, I have seen no evidence whatsoever that there was anything wrong, at all, with the second scope jacekowski showed pictures from.
Something else I've observed is that low signal levels, in most combinations of settings, if not all, the RTB runs at a much slower waveform update rate when compared to the MSO, which I find annoying when trying to see what low-level signals actually look like. Though I haven't actually done extensive testing, it just feels like the MSO, in many cases, provides significantly more information about the dynamic nature of the signal at low levels, largely because of the much higher waveform refresh rate. Additionally, the way the Rigol displays the waveforms and handles persistence, just looks really good.
In actual daily use, the MSO scopes here tend to get more use than the RTB scopes, primarily due to the larger number of relevant features they have in comparison to the RTB. Also, the controls feel more intuitive and they seem quicker to operate than the lovely looking, but often annoying UI of the RTB. (Talking about the front panel controls and using a mouse, not the touch screen, which I rarely use).
Anyone complaining about the noise on the MSO who hasn't actually used one day in and day out might want to reconsider being so vocal about how dire the MSO noise issues are, as I believe they may be doing quite a disservice to potential users for whom the MSO could be an extremely useful tool. The feature set on the MSO is still quite extraordinary for the price, and allows a wide array of signal analysis techniques to be applied. It really is a high-quality "Swiss-Army-Knife" that is unbeatable for the price (if "enhanced", that is).
For the wide variety of work done here, the MSO can do more than the RTB (faster decoding, multiple FFTs, 2 AWGs, area triggering options, higher waveform update rate, more sophisticated and varied triggering options, and more I'm not thinking of right now. In fact after being disappointed at the limited bps UART decoding rates and, at the time, limit of 4 simultaneous measurements of the RTB, it was decided to try out the MSO scopes and they have proved to be more capable for the wide variety of work done here.
Yes, the noise can be annoying in some relatively rare use cases, but there are the various "noise reduction" functions available (although they aren't all that satisfying for my use much of the time), but also the "color grade" function can help to display more detail about the signal. And, anyone thinking an 8-bit scope is going to be the most useful tool for 16/24/32 bit audio signal analysis is likely to be disappointed. There are probably better tools for that sort of work.
Also, if someone spends the majority of their time in the 1 mV/div and below range, there are likely better tools for that as well, but don't forget to consider the waveform update rate in those cases, too.
As for the Siglent scopes, those still are not under consideration here because of their choice of implementation of the zoom function, but also, comparable models were not available at the time the MSO scopes were purchased. There is a lot to like with the Siglents it appears, but I would have to make sure they have the same rich array of functionality as the Rigols, higher waveform update rates, as well as zoom capabilities more in line with the RTB and MSO.
Though the Rigol is far from perfect (UI can get sluggish, but not much worse than the RTB, the web UI isn't nearly as nice as the RTB, and the screen is smaller than the RTB, and yes, there is a noticeable difference in low level signal noise levels), but for the daily tasks here, the Rigol just can't be beat for $$/function. It's a high performance workhorse with a surprising range of capabilities, and has been a great investment, as have all the Rigol scopes purchased here over the years. Yep, I'm a happy user, but looking forward to seeing what Siglent is up to in the future as well...
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