INSTRUMENTATION PHASE LOCKED LOOP

Abstract

Near to optimal design of the high-precision phase-locked loop (PLL), which is intended for use in phase-sensitive measuring instruments is considered in this paper. Minimisation of the steady-state phase error and the transient response time is established as a guide post for design to meet accuracy requirements for measurement applications. Optimization of the parameters of the second order and the third order linearized PLLs is carried out. The conclusion is drawn that the third order PLL exceeds the second order one not only by the far better steady-state accuracy, but also by the faster transient response. The computer aided simulation is used for studying the nonlinear effects in the real nonlinear PLL. It is concluded that the suboptimal third order PLL is able to satisfy the requirements for the phase error within the limits of ±0.1 o.