Modulation

In electronics, modulation is the process of varying one or more properties of high frequency periodic waveform called the carrier signal, with respect to a modulating signal. This is done in a similar fashion as amusician may modulate the tone from a musical instrument by varying its volume, timing and pitch. The three key parameters of a periodic waveform are its amplitude ("volume"), its phase ("timing") and itsfrequency ("pitch"), all of which can be modified in accordance with a low frequency signal to obtain the modulated signal. Typically a high-frequency sinusoid waveform is used as carrier signal, but a square wave pulse train may also occur.

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