Frequency deviation

Frequency deviation (Δf) is used in FM radio

Frequency modulation

In telecommunications, frequency modulation conveys information over a carrier wave by varying its frequency . In analog applications, the instantaneous frequency of the carrier is directly proportional to the instantaneous value of the input signal...

 to describe the maximum instantaneous difference between an FM modulated frequency and the nominal carrier frequency

Center frequency

In electrical engineering and telecommunications, the center frequency of a filter or channel is a measure of a central frequency between the upper and lower cutoff frequencies...

. The term is sometimes mistakenly used as synonymous with frequency drift

Frequency drift

In electrical engineering, and particularly in telecommunications, frequency drift is an unintended and generally arbitrary offset of an oscillator from its nominal frequency...

, 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

Frequency spectrum

Familiar concepts associated with a frequency are colors, musical notes, radio/TV channels, and even the regular rotation of the earth. A source of light can have many colors mixed together and in different amounts . A rainbow, or prism, sends the different frequencies in different directions,...

.

Frequency deviation (Δf) is used in FM radio

Frequency modulation

In telecommunications, frequency modulation conveys information over a carrier wave by varying its frequency . In analog applications, the instantaneous frequency of the carrier is directly proportional to the instantaneous value of the input signal...

 to describe the maximum instantaneous difference between an FM modulated frequency and the nominal carrier frequency

Center frequency

In electrical engineering and telecommunications, the center frequency of a filter or channel is a measure of a central frequency between the upper and lower cutoff frequencies...

. The term is sometimes mistakenly used as synonymous with frequency drift

Frequency drift

In electrical engineering, and particularly in telecommunications, frequency drift is an unintended and generally arbitrary offset of an oscillator from its nominal frequency...

, 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

Frequency spectrum

Familiar concepts associated with a frequency are colors, musical notes, radio/TV channels, and even the regular rotation of the earth. A source of light can have many colors mixed together and in different amounts . A rainbow, or prism, sends the different frequencies in different directions,...

. The FM broadcasting

FM broadcasting

FM broadcasting is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation to provide high-fidelity sound over broadcast radio.-Terminology:...

 range (88-108 MHz) uses a channel spacing of 200 kHz, with a maximum frequency deviation of 75 kHz, leaving a 25 kHz buffer above and below the center frequency to reduce interaction with other channels.http://hyperphysics.phy-astr.gsu.edu/hbase/audio/radio.html AM broadcasting

AM broadcasting

AM broadcasting is the process of radio broadcasting using amplitude modulation.-History:AM was the dominant method of broadcasting during the first eighty years of the 20th century and remains widely used into the 21st....

 uses a channel spacing of 10 kHz, but with amplitude modulation

Amplitude modulation

Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...

frequency deviation is irrelevant.

FM applications use peak deviations of 75 kHz (200 kHz spacing), 5 kHz (25 kHz spacing), 2.25 kHz (12.5 kHz spacing), and 2 kHz (8.33 kHz spacing).http://www.rsgb-spectrumforum.org.uk/Papers/VHF/Davos%20C5%20Papers/DV05_C5_17%20SARL%20NBFM.pdf