That is why I am interested in how the Siglent does when running at 200MHz & 500MSa/s - for all I know it could have similar behavior!
What you see on the Rigol isn't a bug, it's exactly what the math says will happen if you only apply Sin(x)/x to a few samples on either side of the pixel of interest.
That's the same spec as the existing 2 ch SDS1202X-E.
Do remember that these 4 channel X-E's have the same inputs but doubled, 2 ADC's and 2 lots of 14 Mpts memory.
I have taken screenshots at 500 and 250 Msa/s. I have reduced the memory depth to the minimum and in order to go down to 250 Msa/s I have used a slower timebase. The screenshots have been taken with SINGLE trigger in all cases.
Also you can do single shot and in stop mode you can switch between vector or Sinc interpolation or turn it to without interpolation - just dots. There you can see how it solve Sinc. (also Siglent do not draw extra fake dots as some other scopes may do in "dots" mode). Reducing sample speed and using window zoom you may find some results where it can visually see more clearly. In these images we can see there is also real overshoots and not only Sinc made overshoots what are other things. (front end BW filtering do not have enough steep stop before Nyquist for reject aliasing.)
What is miss is: True sample dots highlight On/Off function when Sinc or Vectors in use.
I would say that this scope has a very serious issue when sharing the A/D converter with more than one channel.
The Siglent behaves much better.
I overlaid the Rigol waveform on the Siglent waveform in a single image. As you can see they're identical when you view the wave with the same settings.I would say that this scope has a very serious issue when sharing the A/D converter with more than one channel.
There's more than one channel enabled in the image above...The Siglent behaves much better.
There's a major difference: The Rigol drops down to 250Ms/sec when you turn on the third channel, the Siglent doesn't (because it's only 2 channels).
At 5ns per division there's 1.25 samples per division on screen. I'm not sure how they're aligning the trigger point so exactly but it looks like they're not offsetting the rest of the wave to match. The "jitter" looks to be about 1/1.25 of a square.
There's a major difference: The Rigol drops down to 250Ms/sec when you turn on the third channel, the Siglent doesn't (because it's only 2 channels).
Identical? This is total false. If you use identical input then they can compare. Do these image have exactly same signal?
Even Keysight and Tek share AD converters usually. Keep in mind you also need the hardware to support that converter and to process the data from it. These things run hot, are power hungry, and dump up to 8 or 16 Gbps of data into your FPGA and memory, not to mention the timing constraints. So it's perfectly reasonable to share ADCs between channels if you're short on money.
I overlaid the Rigol waveform on the Siglent waveform in a single image. As you can see they're identical when you view the wave with the same settings.
Anyway, I was mainly trying to point out why the premium for the SDS1104X-E over the DS1054Z might be worth it even at 100MHz.
I don't have Leo's gen.. (It's on a list :-)
This is my old Hameg 8030-6, at 11 something MHz.. Horrible square..
But let's put that on the side...
Running 4 ch, no Jitter... Dot mode and vector mode...
When running 1GS an 500 GS/sec it is bit cleaner but looks the same.
You should run self cal to see if it helps. I realized that it is necessary to do self cal often.
Regards,
Sinisa
Yes, that's 1 Gsa/s. It gets interesting when you go to 500 Msa/s.
Note that I'm not criticizing the SDS1202X-E. sin(x)/x interpolation invents data of course. But it's a similar effect to that of an analog oscilloscope "filling the gaps"
Is there a reason why your screenshots are done with AC trigger coupling ?
As can see it can handle signal what do not have so high frequency components. This signal do not have. Signal rise and fall times are very slow. 250MSa/s even with false Sin(x)/x can handle this kind of signal thumbs down. Sample interval is 4ns. Serious problems start with much faster signal rise/fall times.
I am yet to read the manual but will the Siglent SDS 1000X-E series incorporate a real time clock and in turn allocate time and date stamps to recorded or saved events in stand alone operation, this is important as I regularly monitor systems for glitches and require time stamped events for correlation, leaving a laptop connected and running on a remote site for this particular purpose is not always practical.