Demodulation

[Trebor]

@Smoke_me_a_kipper

I’m investigating an audio file which has some hidden info in it.
I think AM modulation was used, and the carrier signal is 20khz.
How would I go about demodulation / extracting the original (hidden) audio.

If you look at the audio in Audacity’s spectrogram view it will give you the demodulation frequency.