comments to
#2484
>I believe your divider is overcompensated. In the video you got -16ns skew a about 4ns risetime, now at 13ns risetime it is only -8ns skew.
Dont look at the fixed skew, i played with the settings in the deskew menu, and i expect all other users will do the same, it is a cable length compensation factor,
none of us will use the same factor here.
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#2486
>Can you explain why you think there is some kind of "bug" in scope.
the 2nS digital time resolution i understand and accept.
BUT the bug as i see it, is the RANDOM time jitter from digital to analog, it is also within the 2nS sample time,
but it is RANDOM, I would expect it to jump in fixed 2nS hops, not anythng in between,
it looks like someone tried to smooth this, or avarage it, by adding random time jitter.
>This LA Diy project is interesting and nice project so I think it earn its own thread where these things can keep concentrated to just it.
YES Agree, there is, mine is here:
https://www.eevblog.com/forum/testgear/diy-logic-analyzer-probe-and-pods-for-siglent-scopes/but all this is more related to general usage of LA and analogs, and triggers, and skew, deskew adjustment,
the fixed and the random jitter, all this apply (like we have proven) to any type of LA hardware, DIY or original.
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#2489
>Digital threshold was set to 1.6V, same as the analog channel.
>If I bring the digital threshold down to 1.13V, I can get the skew to zero on rising and falling edge
YES if the incoming wave is with rise/fall times slower that the skew, changing digital trigger point, will "move" the curve seen on screen in time,
however this is not the right way, better to have the trigger in the middle and use the deskew feature to correct the cable length difference.
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#2490
>The cases appear to be ultrasonically welded, so it would be destructive to get a look inside, sorry.
darn it.. but thanks alot for looking into it anyways,
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#2491
>Yes there is some digital to analog jitter but where from ?
YES your jitter looks the same as all ours, about 2nS and random,
you would expect it to be in fixed 2nS jumps.
This scope got a VERY fast timebase, to be used for its very fast scope features, however when combined with LA
the user must use a timebase of max 50nS/div or even better 100nS/div, this the random jitter is completely gone (invisible)
and we can focus on our real work and debugging of our hardware and software designs :-)