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For the musical use of "modulation", see modulation (music).

Modulation describes a range of techniques for encoding information on a carrier signal, typically a sine-wave signal. A device that performs modulation is known as a modulator.

Modulation techniques include:

When OFDM is used in conjunction with channel coding techniques, it is described as Coded orthogonal frequency division modulation (COFDM).

Pulse modulation techniques include:

Where the signal is a simple low speed on-off indication, as in morse code or radioteletype (RTTY) transmission, modulation is often known as 'keying' as in the terms

RTTY can also be regarded as a simple kind of pulse code modulation.

Where Morse code is used to turn the carrier wave on and off, the term used is not amplitude keying, but continuous wave (CW) operation.

Modulation is frequently used in conjunction with various channel access methods.

See also:

External links

  • "Data Encoding Techniques" and "Specifications for Data Encoding" discuss the various encoding techniques that have been used with various types of Ethernet.

Last updated: 02-10-2005 22:11:08
Last updated: 02-19-2005 10:47:22