Amplitude Modulation

Modulation is the alteration of the amplitude, phase, or frequency of an oscillator by another signal.

Carrier: the oscillator being modulated Modulator: the altering signal

The spectral components generated by a modulated signal are called sidebands (or heterodynes).

Three main techniques of amplitude modulation are:

• Ring modulation
• ``Classical'' amplitude modulation
• Single-sideband modulation

(we will not discuss the last one).