Phase Shift Keying (PSK) is a digital modulation technique used to transmit data by varying the phase of a carrier wave. In PSK, information is encoded in the phase shifts of the signal, allowing for efficient data transmission over communication channels. Common types of PSK include Binary Phase Shift Keying (BPSK) and Quadrature Phase Shift Keying (QPSK), which differ in the number of phase states used. PSK is widely used in various applications, including wireless communication, satellite communication, and digital television. Its robustness against noise and interference makes it a popular choice for reliable data transmission in modern communication systems.