Wayne Parham Messages: 18793 Registered: January 2001
Illuminati (33rd Degree)
I agree with you about the Behringer amp/ADC/DAC. It has a variety of settings I can adjust - both analog and digital - so I think I can probably dial it in a little better. I was able to get a lot of useful information from it straight out of the box though.
What isn't maybe immediately obvious from the charts I attached in this thread is that the UHF artifacts I saw usually happened when I presented HF sines. To be more specific, sines above 1kHz were more likely to create these artifacts than lower frequencies, and signals above 10kHz almost always did. It didn't seem to be related to amplitude either, which would seem to reduce the likelihood that the problem was from clipping somewhere in the signal chain. It really appeared to be an aliasing artifact or an anomaly from a non-linear anti-aliasing filter. Could be a little of both.
But that's just seat-of-the-pants conjecture on my part. I'll need some more time with this Behringer unit and its device driver to form a conclusion.