modulation

n 1: a musical passage moving from one key to another [syn: {transition}]

2: (electronics) the transmission of a signal by imposing it on

a carrier wave by changing the carrier's amplitude or

frequency or phase

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)