Amplitude Modulation

Modulation is the alteration of the amplitude, phase, or frequency of an oscillator in accordance with another signal.

The oscillator being modulated is the carrier, and the altering signal is called the modulator.

Amplitude modulation, therefore, is the alteration of the amplitude of a carrier by a modulator.

The spectral components generated by a modulated signal are called sidebands.

There are three main techniques of amplitude modulation:

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