Coherent Differential Phase Shift Keying (CDPSK) is a phase shift keying technique in which the phase of the carrier frequency
is modulated separately. The phase shift keying used in CDPSK modulation is the modulation phase position
inrelation to the phase of the reference signal. The modulation is performed with the digitaldata
In CDPSK modulation, the carrier frequency and amplitude remain constant. A phase comparison is made between two consecutive pulses and the information is obtained from the phase shift between the phase position of the carrier signal and that of the pulses.