DQPSK Differential Quadrature Phase Shift Keying
Differential Quadrature Phase Shift Keying is a modulation technique in which the carrier can assume one of four phases, each change of phase, or symbol, representing 2bits. The bit combinations being 00, 01, 11 and 10. Consequently the data stream can carry 2bits at a time. Using this technique the phase transition across the origin is avoided.
