三阶锁相环环路滤波器参数设计

锁相环在通信、遥测、导航等领域有着广泛的应用,三阶锁相环由于其频率斜率跟踪能力,越来越受到重视,特别是深空探测的极窄带应用。利用系统稳定性分析方法和高阶系统分析理论,分别对两种模型的二阶环路滤波器,即理想二阶滤波器和三参数滤波器模型,推导了参数设计公式,给出三阶锁相环设计参数的模拟及数字环路公式,并与JPL数字锁相环(DPLL)的设计参数经验公式进行比较。仿真结果表明,3种设计方法近似相同,而所推导的参数设计方法优点在于可以灵活配置系统的零、极点的位置以及阻尼系数等多种参数,为各种变带宽和自适应算法提供理论和应用基础。

Parameter Design for Loop Filter of Third-order PLL

PLL has the wide application in communication,telemetry and navigation field.Because of frequency slope tracking capability,the third-order PLL gets more and more attention in the very narrowband application for deep space exploration.By using of system stability analysis methods and high-order system analysis theory,the parameter designing formulas of two kinds of second-order loop filters which are ideal second-order and three-parameter filters are derived respectively.The analog and digital loop formulas of third-order PLL designing parameters are provided,and also compared with experienced formulas of JPL''s DPLL designing parameters.The simulation results show that the three kinds of methods are similar,but the position of system zero points,pole points and dumping parameter in this deduced parameters design method can be set freely,so it can provide principles and application basis for each kind of variable bandwidth and adaptive algorithm.