Demodulation (signal detection) is the process opposite to modulation of a radio signal, namely the extraction of the informational (modulating) signal from a modulated high-frequency oscillation.
Detection is the process opposite to modulation, in which a detector extracts the modulating signal from the modulated oscillation. The simplest form of detection is implemented using a nonlinear element, most commonly a diode.
Amplitude modulation (AM) signal demodulation can be performed in several ways. The simplest method is full-wave detection (calculation of the absolute value of the signal) followed by smoothing the resulting unipolar carrier pulses with a low-pass filter.
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