Basic PLL Theory

In this chapter1, we first consider the basic theory of the PLL and explore some of its operating characteristics. No attempt is made to present a complete or unified treatment since this is more than adequately accomplished in the literature. There are a number of excellent textbooks that treat the PLL in considerable detail as listed in Bibliography. Our aim, however, is to develop the theory to a point that allows us to develop and understand a number of simple models for these interesting and useful devices. We then turn our attention in the following chapter to several important structures for demodulation and tracking that are derived from the basic PLL. These include the Costas PLL, the QPSK tracking loop, and the N-phase tracking loop. MATLAB simulations based on these models are then developed as described in Chapter 4 and 5.