coherent differential phase shift keying (CDPSK)
Coherent Differential PhaseShift Keying (CDPSK) is a phase shift keying in which the phase of the carrier frequency is modulated separately.
The phase shift keying used in CDPSK modulation is the modulation phase position in relation to the phase of the reference signal. The modulation is performed with the digitaldata to be transmitted.
In CDPSK modulation, the carrier frequency and amplitude remain constant. A phase comparison is made between two successive pulses and the information is obtained from the phase shift between the phase position of the carrier signal and that of the pulses.