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Sub: Rigol's DHO800 Oscilloscope (Gibbs Effect & Aliasing Misunderstanding)
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Martin72:
I had read through the whitepaper I linked to and connected the bodnar pulser to the scope again, in this case the DHO804(100Mhz).
The signal from the bodnar is 10Mhz, so it should be interpolated cleanly, regardless of whether linear interpolation or sinx/x is used.
But it doesn't, even at 1.25GSa/s you can already "discover" something and in the worst case, the 312.5MSa/s, it already looks pretty blurred.
This can only have something to do with the very fast rise time of the signal(~40ps).
So I fed in a square wave signal from the SDG2122X with the same frequency and amplitude.
The only difference is that the signal is very "slow" in terms of rise time - 9ns, which shouldn't be a problem for the interpolation, and lo and behold, it is.
(Why the "roof" looks so "wobbly", I'll have another look tomorrow).
Now I also understand the behavior of the DHO4204, thanks for the food for thought@rf-loop.

Mechatrommer:
3ns sample interval... 0.04ns risetime, how many points? 3ns sample interval... 9ns risetime, how many points? Just for thinking.. too bad dho cannot show dots... harder to think... 2GSa/s also Gibbs ;D
nctnico:
The only thing that matters where it comes to getting Gibbs ears (as in reconstruction artefacts) is when the signal your are measuring becomes a step response in the sampled aka digital domain. You really need to think about what a sampled signal looks like in the digital domain and how that depends on the samplerate.
bdunham7:

--- Quote from: Mechatrommer on November 05, 2023, 12:16:05 am --- too bad dho cannot show dots...

--- End quote ---

Is that true--it does not have a dot mode?
Martin72:
Yepp, no dot mode and no interpolation choice.
Neither the smallest (DHO800) nor the largest (DHO4000) model.
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