otherguy

@attila thank you for getting back to me. Sorry for the delayed response, I must have missed the notification that you had replied. The first screenshot (with open circuit UTP cable)makes sense to me. I don't have experience running tests like this with a shorted cable, but I'd suspect at low frequencies, the inductive and capacitive components of the impedance to be negligible, and the resistance to be low (if shorted)... seems like the traces in the second screenshot illustrate that. I'm not familiar with the WaveForms user interface, so not sure what the difference is between the dotted and solid orange traces. From your data peovided, it seems like it's worth a time and $ investment on my side to evaluate suitability further. Could you describe the physical circuit configuration, any special breakout boards you're using, and what modes/settings you've used to performed these tests? I see the graphic in the upper right of your screenshots, but I'm not sure how that compares to where you have physical components connected. Thanks again!

Any luck engaging the WaveForms developer?

It looks to me like you've left both ends of the black conductor disconnected in your circuit I don't think this setup will correctly measure the characteristic impedance of the twisted pair. In your setup would you not just be measuring resistance and ignoring the inductive and capacitive reactance of the transmission line?

I have a project which requires performing impedance measurements on a variety of twisted pair cables. I'm trying to evaluate whether the analog discovery2/3/pro & Waveforms are suitable for my needs. Reviewing the documentation for Impedance Analyzer its not immediately clear to me how measurement of a transmission line (length of twisted pair cable) could be accomplished with the given topology arrangement options. It seems like the hardware should be capable of performing the task though. How could one wire a transmission line to the Analog Discovery device for the purpose of running the Impedance Analyzer? If this is not currently supported in Waveforms, would it be possible to perform this test using the Waveforms SDK/pydwf? Thanks!