Diode & Filter Applications in Amplitude Modulation (AM) Detection Circuits

The operation of a typical AM audio frequency signal is illustrated in the Figure 1.0 where v_in is the modulated signal that is shown Figure 1.1.

A typical amplitude modulated signal that is fed into the detector circuit:

The diode removes the lower envelope and the upper envelope is illustrated below:

The capacitor C₂ and resistor R₂ form a high-pass filter that removes the carrier frequency, and the output v_out is the audio signal as illustrated in Figure 1.2:

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