I am working on an embedded audio emitter/receiver, based on the TLV320AIC3254 codec, the CC8520 audio streamer and CC2590 front end.
It functionnaly works well, eihter as a simple a recorder, or an emitter or a receiver. However, I noticed an annoying noise when transmition is ON.
It is not a random noise, it has big regular harmonics : 125Hz, 250Hz, 500Hz, 750Hz... Even worse in emitter mode, these harmonics are stronger and 3 sub-harmonics appear between each of them, making it sound horrible. It could have been kind of interference within my layout, although none of my ICs are runnnig at this frequency ! Therefore I assume it comes from internal artifact...
Does anyone experienced such an intermodulation distortion with these ICs ? Is there a way to avoid it ?