Inject noise to start carrier oscillator. Carrier wave is passed through a CMOS inverter. The signal wave is shifted up and inverted. This splits the signal into a differential pair of waveforms with one waveform shifted up and the other shifted down and 180 degrees out of phase. The up-shifted waveform is used to clamp the high rail of the CMOS inverter and the down-shifted waveform clamps the low rail. The resultant output is the carrier wave with an amplitude modulated by the signal wave.
