What type of modulation is primarily used in FM broadcasting?

Frequency modulation is the primary modulation type used in FM broadcasting because it varies the frequency of the carrier wave in accordance with the amplitude of the input signal, which is typically audio in this context. This technique allows FM radio to achieve high sound quality and resistance to noise and interference, resulting in a clearer audio signal compared to other modulation methods, such as amplitude modulation.

In FM broadcasting, the audio information modifies the carrier wave's frequency, causing shifts that correspond to the variations in the sound signal. This means that loud sounds increase the frequency deviation, while softer sounds decrease it, thus preserving the integrity of the original audio quality during transmission.

Furthermore, the characteristics of frequency modulation make it particularly suitable for broadcasting, as it offers better fidelity for music and speech, and is less susceptible to amplitude noise, which can drastically affect sound quality in amplitude modulation systems. This reliability and enhanced performance in various environments solidify frequency modulation's place as the dominant method for audio broadcasting in FM radio.