在数字通信系统中,用于相位估值而广泛采用的非线性反馈系统是一种锁相环。如果传送的信号在载频上含有残余的载波分量,则锁相环可用来跟踪载波相位。另一方面,信号的调制分量也含有载波的相位信息。本文讨论并分析一种组合调制分量和载波分量来供相位估值的系统。此系统由两种类型的锁相环组合而成。 In digital communication systems, a widely used nonlinear feedback system for phase estimation is a phase-locked loop. The phase locked loop can be used to track the carrier phase if the transmitted signal contains residual carrier components at the carrier frequency. On the other hand, the modulation component of the signal also contains the phase information of the carrier. This article discusses and analyzes a system that combines a modulation component and a carrier component for phase estimation. This system consists of two types of PLLs.