基于权值调整的FLL辅助PLL方法

The FLL assisted PLL method based on the weights adjustment

锁相环技术越来越广泛应用于雷达、导航设备、空间技术等方面,特别是近年来在高动态信号环境中的应用更为广泛,但在此环境中存在环路带宽和高信噪比的矛盾,跟踪高动态信号时需要增加环路的带宽,但在增加带宽的同时会导致信噪比降低,反之,提高信噪比必须减少带宽。文中利用FLL有较高动态性能的特点,采用了FLL辅助PLL的方法来解决这对矛盾。而FLL辅助PLL的方法有多种,文中首先介绍了FLL/PLL(FLL牵引PLL)和FLL&PLL(FLL与PLL)的辅助方法原理及优缺点,最后通过改进采用了基于权值调整的FLL辅助PLL的方法,并用VHDL对它进行了设计,最后对三种方法进行了仿真验证。

The phase - locked loop technology has been widely used in radar, navigation equipment, and space technology, especially in the environment of high dynamic signal in recent years. There exists, how- ever, a conflict between the loop bandwidth and the high SNR in this environment, i.e. the need to in- crease the bandwidth of the loop when tracking high dynamic signal leads to reduction of SNR, which can only be improved by decreasing the bandwidth. FLL, which has higher dynamic performance, is used to as- sist PLL to resolve this contradiction. The article first introduces the principle, advantages and disadvantages of FLL/PLL and FLL＆PLL, then puts forward a method of FLL assisted PLL based on the weights adjust- ment and uses VHDL to design it, and finally verifies the validity of this method by simulation.