The operation of the phase-lock loop
We examine the operation of the phase-lock loop (PLL). The PLL is one of the fundamental tools of the electrical engineer. It is nonlinear, and its operation is usually examined only after a number of simplifying assumptions are made. We derive an equation that governs this tool's operation and determine the properties of the solutions of the equation. We show that the linear time invariant approximation that is generally used to model the PLL is a good approximation to the original nonlinear time-varying equation. (C) 2000 Elsevier Science Ltd. All rights reserved.
phase-lock loop the mathieu equation nonlinear control theory