AM (Amplitude Modulation)

A means of convenying information on a carrier wave by varying its instantaneous amplitude. In an audio application, like AM radio, the wanted audio signal's amplitude is used to create corresponding deviations in the carrier wave's amplitude.  A demodulator can detect these deviations and thus recover the base-band audio signal. This form of modulation contrasts with frequency modulation (FM) where the carrier wave's amplitude remains constant but its frequency is varied to convey the wanted signal.