intermediate frequency

In electronics, an intermediate frequency (IF) is a relatively low frequency to which a signal is converted before it is demodulated. This process is a key part of superheterodyne reception, a technique used in most radio, television, and radar receivers.123

In a superheterodyne receiver, the incoming high-frequency signal is mixed with a lower-frequency current generated within the receiver. This creates a new frequency, the IF, which is the difference between the original frequencies. The IF is easier to amplify with high gain and selectivity than the original high frequency. Common IFs include 455 kilohertz for AM radios, 10.7 megahertz for FM radios, and 38 megahertz for television receivers. Radio-frequency integrated circuits (RFICs), used in devices like mobile phones, operate in a much higher frequency range, typically from 3 kHz to 2.4 GHz.234