锁相回路可视为一个输出相位和输入相位的回授系统用以同步输入参考讯号和回授后输出信号。并让其操作同样的频率。如(图一)所示，简单锁相回路[3,4]是由三个电路构成，分别为相位侦测器（Phase Detector）、回路滤波器（Loop Filter）、压控荡器（VCO）-phase-locked loop can be regarded as a phase output and input phase feedback system for synchronous reference input and feedback signals After the output signal. And allowed to operate the same frequency. If (Figure 1), the simple lock-loop [3,4] by the three circuit. for the detection phase (Phase Detector), loop filter (Loop Filter), VCO finishes (VCO)