intermediate frequency

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.

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.

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