Maybe you can describe this a bit more. The Great Seal Bug was used for wireless audio recording in the 40's, but this operated by using a microphone/cavity to modulate the load of an antenna; thereby embedding audio in the reflected fields.
Bell did a similar demonstration in the 1890s using a mirror to embed reflections in ambient light and demonstrated wireless audio transmission over 200 meters.
However, I'm not sure why audio would cause a frequency shift in a radio circuit. Perhaps you are meaning the antenna will be perturbed and that could possibly be recovered? I'd be interested to know.
Bell did a similar demonstration in the 1890s using a mirror to embed reflections in ambient light and demonstrated wireless audio transmission over 200 meters.
However, I'm not sure why audio would cause a frequency shift in a radio circuit. Perhaps you are meaning the antenna will be perturbed and that could possibly be recovered? I'd be interested to know.