What is the concept of angle modulation?

Angle modulation is a technique used to modify a carrier signal's phase or frequency in response to a modulating signal. The modulating signal contains the information that needs to be transmitted, and the carrier signal is used to carry this information over a communication channel.

In frequency modulation (FM), the carrier signal's frequency is varied in proportion to the amplitude of the modulating signal. The frequency deviation, or the extent to which the carrier frequency varies, is directly proportional to the amplitude of the modulating signal. As the amplitude of the modulating signal changes, the frequency of the carrier signal changes correspondingly. This results in a signal that has a constantly varying frequency, which can be used to transmit information.

In phase modulation (PM), the carrier signal's phase is varied in proportion to the amplitude of the modulating signal. As the amplitude of the modulating signal changes, the phase of the carrier signal changes correspondingly. This results in a signal that has a constantly varying phase, which can also be used to transmit information.

Both FM and PM are examples of angle modulation, as they modify the angle of the carrier signal in order to carry information. Angle modulation is widely used in telecommunications, including radio and television broadcasting, satellite communication, and digital communication systems.