Crosstalk with BNC 2120, PCI-MIO-16E-4 (6040E), and e57891 cable

[pdan]

I'm measuring some pretty slow signals (on the order of 1 kHz) using the AI acquire multiple waveforms.vi with the default settings (except for the sample rate) and I'm seeing about -9dB crosstalk. I don't think it's in the rest of my setup, since I don't see any problems when I plug my BNC cables into an oscilloscope. I can't seem to find crosstalk specs for any of the parts in the title, but I have a hard time believing that this is strictly a hardware problem. Is there something I'm missing that might be causing this problem?

[George M.]

Hi,

Here is a great KnowledgeBase discussing Cross-Talk issues, and some different solutions:

http://ae.natinst.com/operations/ae/public.nsf/web/searchinternal/b9bcdfd960c06b9186256a37007490cd?OpenDocument

I hope this helps. Have a Great Day!

George

[pdan]

Thanks for that link.

I fixed my problem, but now I'm wondering why what I did fixed it. Sampling the channels in the other order fixed it, but I don't see any reason why it should. Both of the input devices have identical resistive and capacitive loads, the signals only differ in magnitude by about 50%, and I have the same gain settings for both channels. Is there any other sort of asymmetry that would cause that fix to work? I don't like the idea of using this without really understanding why it's working.

[George M.]

Hi,

This more than likely has to do with the settling time between channels. I'm glad this worked for you.

Have a Great Day!

George