Hi,
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called heterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. There may be several such stages of intermediate frequency in a superheterodyne, which is called double (or triple) conversion.
Perhaps the most commonly used intermediate frequencies are around 455 kHz for AM receivers and 10.7 MHz for FM receivers. However, the intermediate frequency can range from 10–100 MHz. Intermediate frequency (IF) are generated by mixing the RF and LO frequency together to create a lower frequency called IF.