DQPSK - technical definition

Also known as Differential Quadrature PhaseShift Keying. A variation on the QPSK modulation technique, DQPSK relies on the difference between successive phases of a signal rather than the absolute phase position. DQPSK is commonly used in cellular radio systems and other radio systems, such as LMDS. See also cellular radio, LMDS, /4 DQPSK, PSK, and QPSK.