Phase modulation is widely used for transmitting radio waves and is an integral part of many digital transmission coding schemes that underlie a wide range of technologies like Wi-Fi, GSM and satellite television.

What is an example of phase modulation?

For digital signals, phase modulation (PM) is widely used in conjunction with amplitude modulation (AM). For example, quadrature amplitude modulation (QAM) uses both phase and amplitude modulation to create different binary states for transmission (see QAM).

What is the main advantage of using a phase modulator rather than a direct frequency modulation?

Eventhough the crystal oscillators with varactor is widely used in FM transmitters, the moderm FM modulators uses modulators that works on phase modulation. The main cause to adopt phase modulation instead of direct FM is the carrier oscillator can be adjusted to an optimum value of carrier frequency and is stable.