Amplitude Shift Keying (ASK) is a type of digital modulation technique used in communication systems. In ASK, the amplitude of a carrier wave is varied to represent digital data. For example, a high amplitude might represent a binary '1', while a low amplitude represents a binary '0'. This allows the transmission of data over radio waves or other mediums. ASK is simple to implement and is often used in low-frequency applications, such as radio transmitters and remote controls. However, it is more susceptible to noise and interference compared to other modulation techniques, which can affect the quality of the received signal.