I am experiencing an issue with headset audio input/output.
There is a high pitched whine on the audio lines that can be heard at the outputs and recorded at the inputs.
I’ve recorded a short audio file and analyzed it only to find that there are several harmonics - it peaks at about 4100Hz (-65dB), 8200Hz (-70dB), 12300Hz (-68dB), 16400 (-70dB).
A colleague who’s an electronics engineer, recommended using various power sources, and also some filtering and the result was about the same. It also seems to not have anything to do with any connected audio equipment since the noise is also present and apparently unchanged when one simply shorts the mic input to the ground (over a 10k resistor for just in case ;))
I’d really appreciate any advice on the matter.