高稳定BPSK信号载波相位同步算法

A High Stable BPSK Carrier Phase Recovery Algorithm

基于二相相移键控(BPSK)信号幅度剧烈变化会严重影响数字锁相环的环路带宽和稳定性,提出了一种数字自动增益控制(AGC)和锁相环(PLL)联合的高稳定BPSK信号载波相位同步算法.采用指数增益放大非相关反馈自动增益控制环路对输入调制信号进行幅度调整,使输出AGC的调制信号幅度稳定在预定值,再将幅度稳定调制信号输入到数字三阶PLL进行精确载波相位估计.仿真结果表明,算法避免了数字三阶PLL由于调制信号幅度变化带来的环路不稳定,且在信噪比(SNR)动态范围内,保证环路噪声性能满足BPSK信号解调的要求.

Acute change of BPSK signal amplitude seriously affects the PLL＇s bandwidth and stability. A high stable synchronization algorithm for BPSK carrier phase is presented in this article that unifies the techniques of digital automatic gain controller （DAGC） and DPLL. The non-coherent DAGC, which adopts an exponential gain controlled amplifier, adjusts the modulated signal amplitude to the settled value, and then the amplitude-stable signal input to the third order DPLL to recovery accurate carrier phase. Simulation results confirm that the presented algorithm could prevent the instability of third order DPLL from the change of signal amplitude. It also satisfies the requirements of BPSK demodulation performance when the signal is within the intended SNR range.