Amplitude modulation

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Amplitude modulation is a method of transmitting information by varying the amplitude of a carrier wave in proportion to a message signal. The carrier's frequency and phase are normally kept constant while its strength changes.

In conventional amplitude modulation, the transmitted spectrum contains the carrier frequency and two sidebands. The upper and lower sidebands contain the same information shifted above and below the carrier.

The modulation depth describes the amount by which the carrier amplitude varies. Excessive modulation can distort the recovered signal, while insufficient modulation reduces efficiency and signal-to-noise performance.

Amplitude modulation has been widely used in radio broadcasting, aviation communication, analogue television, and signal processing. Related forms include double-sideband suppressed-carrier, single-sideband, and quadrature amplitude modulation.

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• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Amplitude_modulation