In the telecommunication era of signal processing the Frequency Modulation encoding technique in the conversion of information by altering the frequency of the given wave.

It shows a contrast with amplitude modulation, in which the amplitude of the carrier wave altered, while the frequency is constant.

In analog type of modulation, such as the FM broadcasting of an audio signal which always represents voice or the music, the deviation in the frequency, the difference between the frequency of the carrier and the center, is proportional to the signal to be modulated.

In such kind of modulation technique, the frequency of the carrier is changed to reflect the change in the voltage level of the modulating signal.

Digital data can be encoded and transmitted via FM by shifting the carrier's frequency among a predefined set of frequencies representing digits

Frequency modulation is widely used for FM radio broadcasting