Analysis of Phase-Locked Loops using the Best Linear Approximation

Abstract

During the early design stage of Phase-Locked Loops, linear models are thoroughly used to analyse the steady-state behaviour. In reality, the envisioned linear performance is degraded due to nonlinearities present in the actual implementation. Lately, a nonlinear modelling technique based on the Best Linear Approximation has been developed which allows to verify the validity of this linear model and, in addition, permits to characterise the nonlinear distortions present in the system. Incorporating this Best Linear Approximation in the design stage allows to intuitively analyse the nonlinear behaviour of the Phase-Locked Loop.