Introduction -- Transmitter Receiver Techniques -- Modulation Techniques and Signal Processing -- Basic Considerations of PLL and Its Types -- Digital Phased Locked Loop -- Synchronization -- A Zero Crossing Algorithm based Digital Phase Locked Loop -- Least Square Polynomial Fitting based Digital Phase Locked Loop -- A DPLL based Recovery System for Nakagami-m Fading Channel -- Coding Assisted Carrier and Symbol Recovery using DPLL -- Carrier Phase Detection of Rayleigh and Rician Faded Signals using Digital Phase Locked Loop -- DPLL based Square Loop for Carrier Synchronization over Fading Channel -- Conclusions and Future Direction.