Granted, this is not Amplitude Modulation per se, but the same rules still apply. The amplitude of the audio signal is superimposed on the carrier, which can be easily demodulated using a simple envelope detector. I've added a little extra bonus demodulation using a notch filter. The last one will usually not work with AM because a detector needs a nonlinear component like a diode to separate the signals, but as i said this is not AM.
