基于 DSP 的高动态锁相环的实现

摘要

文中介绍了常见锁相环的基本结构，分析了相位检测器、环路滤波器和压控振荡器的执行情况。PLL 环路滤波器的系统函数表明，环路滤波器的性能基本上决定了锁相环的质量。侧重于环路滤波器的设计，结合锁相在高动态GPS 接收机环路中的应用，提出了在高动态环境中，一种两相锁频环辅助三相锁相环数字滤波器的细节。模拟结果表明，该锁相环的性能比普通 PLL 已大大改善，并完全符合高动态信号跟踪的要求。%This paper introduces the basic structure of common phase-locked loop,and analyzes implementation of phase detector,loop filter and VCO.System function of PLL loop filter shows that the performance of loop filter basically determines the quality of phase-locked loop.Focusing on the loop filter design,combined with application of PLL in loop of high-dynamic GPS receiver,details of a digital filter in highly dynamic environment with two-phase frequency locked loop aiding a three-phase phase-locked loop are presented.The simulation results show that the proposed PLL has much better performance than common PLL,and is in full compliance with the requirements of high dynamic signal tracking.