In FM communication, what does the term "frequency deviation" refer to?

In FM (Frequency Modulation) communication, "frequency deviation" specifically refers to the maximum deviation of the carrier frequency from its original frequency due to the modulation process. This change is a consequence of varying the instantaneous frequency of the carrier wave in proportion to the amplitude of the input audio signal. The greater the frequency deviation, the more significant the audio signal's impact on the carrier wave, allowing for a more distinct representation of the audio information being transmitted.

To understand this concept fully, it's important to recognize that frequency deviation plays a crucial role in defining the bandwidth of the FM signal and affects the quality of the transmitted audio. When the input signal varies, the carrier frequency shifts up and down within a specific range that is designated as the maximum frequency deviation. This is why the chosen definition effectively encapsulates the essence of the term in the context of FM communication.