An intermediate frequency (IF) is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. It is the beat frequency between the signal and the local oscillator in a radio detection system. IF is also the name of a stage in a superheterodyne receiver. It is where an incoming signal is amplified before final detection is done. There may be several such stages in a superheterodyne radio receiver.
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Commonly used intermediate frequencies ranges are as given below
Television
- 30Mhz to 900MHz
FM radio
- 5.5 MHz
- 10.7 MHz
AM radio
- 455 kHz
- 460 kHz
- 465 kHz
- 470 kHz
- 475 kHz
- 480 kHz
Other
In some double superheterodyne receivers, first an intermediate frequency of 1.6MHz is used followed by a second intermediate frequency of 470kHz.
