三阶软件锁相环变带宽技术研究

Research on Third-order Variable-bandwidth Software PLL

锁相环是连续波测速雷达的核心部件,对测速精度有很大影响。为了提高测速精度,研究三阶软件锁相环的基本原理及变带宽技术。与带宽硬切换的方法不同,采用软切换的方法,对定步长和变步长两种方式进行研究。结果表明,采用合适的变步长方法可以避免带宽变化导致的环路波动,提高多普勒频率提取精度。

Phase-locked loop （PLL） is the core component of continuous wave velocity radar which influences the accuracy greatly. In order to improve the processing accuracy, the fundamental principle and variable-bandwidth method are studied. Different from the hard switching, soft switching method is used. Both fixed-step and variable-step methods are studied. Simulations show that using appropriate variable-step method can avoid loop fluctuation and improve doppler frequency extraction accuracy.