Source : WordNet®

demodulation
     n : (electronics) the reception of a signal by extracting it
         from the carrier wave

Source : Free On-Line Dictionary of Computing

demodulation
     
         To recover the {signal} from the {carrier}.
        For example, in a radio broadcast using {amplitude modulation}
        the audio signal is transmitted as the mean amplitude of a
        radio-frequency carrier so demodulation requires a circuit
        which measures the amplitude and filters out the carrier.
        There are many other kinds of {modulation} and corresponding
        demodulation.
     
        (1998-07-29)