数字锁相环变带宽滤波器的设计与仿真

摘要

对于确定参数的滤波器,快速的相位捕捉能力和高的噪声抑制能力是相互矛盾的.利用数字滤波器参数容易改变的特点,主要研究二阶锁相环环路中变带宽数字滤波器的设计,从而使锁相环路在初始阶段具备快速的捕捉能力和在锁定状态具备高的噪声抑制能力.对数字锁相环系统及滤波器在原理上进行了细致分析,之后给出软件实现该滤波器的算法,并用Matlab对系统进行仿真.%The rapid phase capture capabilities and high noise immunity are mutually contradictory to fixed parameters filters. Parameters in digital system are convenient to set, which benefits realizing variable bandwidth filter. The main is to design a digital variable bandwidth filter in second-order PLL, which makes the system owns fast capture capabilities and high noise immunity both. In this paper, it analyse the principle of Digital Phase Lock Loop system and filter, gives a software algorithm for designing the filter and simulates the system using Matlab.