Phase Modulation Schemes

􀂄Phase shift keying (PSK):Uses two fixed signals with a 180 phase difference to each other to indicate a 0 or a 1 respectively.
􀁺Complex demodulation circuitry needed to recover the reference phase.
􀂄Differential PSK (DPSK):Uses a phase shift of 90 relative to the current signal to indicate a binary 0, and a 270 phase shift for binary 1.
􀁺This has simpler demodulation equipment.