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Siglent SDS1104XE: slanted square wave in c/[email protected]

[–] [email protected] 1 points 1 year ago

Thanks but unfortunately this is not a probe cal problem. Note that the issue is seen even in a 50Ohm environment, no probes.

Siglent SDS1104XE: slanted square wave in c/[email protected]

[–] [email protected] 1 points 1 year ago

Thanks! I tried but I don't see the effect with noise gen, maybe my measurement is not quite right. Simply punching in a couple of frequencies (60Hz and 200Hz) that I've already seen differ in amplitude with the Measure function also has different peak amplitudes in FFT output. Since the frequencies are so low I've verified stability of siggen amplitude output with an AC voltmeter and it's stable within 50uV or so, nowhere near the diff in magnitude measured by the scope. Hmm...

Siglent SDS1104XE: slanted square wave in c/[email protected]

[–] [email protected] 2 points 1 year ago (2 children)

Thanks for taking a look! SG is set to 50Ohm output, cable is 50Ohm, terminated "through" 50Ohm at scope end. Also, SG output looks normal on a different scope (same cable/terminator arrangement). Not sure what else I could do to match the impedance here.

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Siglent SDS1104XE: slanted square wave (imgur.com)

submitted 1 year ago* (last edited 1 year ago) by [email protected] to c/[email protected]

6 comments fedilink

Hi!

I've asked Siglent support but after a couple of responses the thread went cold. Maybe I'm being dumb but I've noticed that there's a frequency (low, around 100Hz) where scope response changes a bit. Below and above it square input looks square. Right about it square input looks slanted.

I tried to do a very slow "sweep" and there's small but visible change in the envelope. So, e.g. with a constant 600mV p2p input lower frequencies measure exactly that while higher ones measure 612mV, so ~2% diff.

Terminated 50Ohm cables (not that it matters at such a low freq) to be sure. Latest firmware, after full self-cal. Siggen itself seems allright, I have an ancient Tek scope and the siggen output looks Ok there with same input/same cables. Scope seems happy and fully functional otherwise, few years old though, out of warranty.

Has anyone else seen anything like that? Is this a normal behavior within the expected margin of error?

Thanks!

How to remove press fit connectors in c/[email protected]

[–] [email protected] 4 points 1 year ago (1 children)

I'd try deoxit first. If that fails, one pin at a time is a lot of work but doable