Intermediate frequency
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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 superhet radio receiver.
Widely used intermediate frequencies are 10.7MHz (FM Radio), 455kHz (AM Radio) and 38MHz (television reception).
Other common intermediate frequencies are in the 35-45MHz range (TV).
Other common intermediate frequencies are 460kHz, 465kHz, 470kHz and 475kHz (AM Radio). In a Double Superhet the first intermediate frequency of 1.6MHz followed by a second intermediate frequency of 470kHz was used in some Communication Receivers.
