Frequency deviation (
) is used in
FM radio
FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is cap ...
to describe the difference between the minimum or maximum extent of a frequency modulated signal, and the nominal center or
carrier frequency
In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an information-bearing signal for the purpose of conveying information. This carrier wave usually has a ...
. The term is sometimes mistakenly used as synonymous with
frequency drift, which is an unintended offset of an oscillator from its nominal frequency.
The frequency deviation of a radio is of particular importance in relation to
bandwidth, because less deviation means that more channels can fit into the same amount of
frequency spectrum. The
FM broadcasting
FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is capab ...
range between 87.5 and 108 MHz uses a typical channel spacing of 100 or 200 kHz, with a maximum frequency deviation of +/-75 kHz, in some cases leaving a buffer above the highest and below the lowest frequency to reduce interaction with other channels.
Radio Broadcast Signals
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The most common FM transmitting applications use peak deviations of +/-75 kHz (100 or 200 kHz spacing), +/-5 kHz (15–25 kHz spacing), +/-2.5 kHz (3.75-12.5 kHz spacing), and +/-2 kHz (8.33 kHz spacing, 7.5 kHz spacing, 6.25 kHz spacing or 5 kHz spacing).
See also
* Frequency modulation
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and computing.
In analog ...
* Carson bandwidth rule In telecommunication, Carson's bandwidth rule defines the approximate bandwidth requirements of communications system components for a carrier signal that is frequency modulated by a continuous or broad spectrum of frequencies rather than a single ...
References
*
{{reflist
Radio modulation modes
Frequency-domain analysis