Basic Considerations of PLL and Its Types

Abstract

PLL is one of the most commonly used circuits in communicationl engineering. An incomplete list of specific tasks accomplished by PLLs include carrier recovery, clock recovery, tracking filters, frequency and phase demodulation, phase modulation, frequency synthesis, and clock synchronization. PLLs find themselves into a huge set of applications, from radio and television, to virtually every type of communications (wireless, telecom, datacom), to virtually all types of storage device, to noise cancellers, and the like. With the widespread use by the public of such devices, one can claim that PLLs are the most ubiquitous form of feedback system built by engineers. This chapter discusses the basic operational principles of PLL. The mathematical models of the various components of PLL are discussed. Both linear and nonlinear model of PLL are explored. Finally, the chapter ends with a representation of PLL in S-domain.