Frequency modulation (FM) is a method of encoding information in a carrier wave by varying its frequency, while keeping the amplitude constant. In FM, the frequency of the carrier wave is changed in proportion to the input signal (such as sound or data) that is being transmitted. This variation in frequency encodes the information, which can then be decoded by the receiver. FM is commonly used in radio broadcasting (e.g., FM radio stations), as it offers better sound quality and resistance to interference compared to amplitude modulation (AM). The amount of frequency deviation is typically related to the amplitude of the input signal. [ChatGPT.com (2024)]