Frequency modulation (FM) is a method used in telecommunications to encode information in a carrier wave by varying the frequency of the wave. In FM, the frequency of the carrier signal is altered in proportion to the amplitude (strength) of the input signal, which could be an audio or data signal.

Unlike amplitude modulation (AM), where the amplitude of the carrier wave is varied to reflect changes in the input signal, FM keeps the amplitude constant and changes the frequency. This modulation technique allows for a more resilient transmission against amplitude variations caused by noise or interference.

FM is widely used in radio broadcasting, particularly in commercial radio stations, due to its high fidelity and ability to deliver clear sound quality. It’s also used in various communication systems, including two-way radios, walkie-talkies, and certain television signals.