Demodulation

The process of separating the original information or signal from the modulated carrier. In the case of amplitude or frequency modulation it involves a device, called a demodulator or detector, which produces a signal corresponding to the instantaneous changes in amplitude or frequency, respectively. This signal corresponds to the original modulating signal.

In radio transmission this process is a major function of a receiver, in order to retrieve the desired signal.

See: Heterodyne, Radio Spectrum.