PSK信号的码速率估计及其多片DSP实现

Symbol rate estimation of PSK and its implementation based on multiple DSPs

针对相位编码(PSK)信号的参数估计问题,研究了PSK信号的码速率估计算法并将其硬件实现。对PSK信号的频谱进行多点平滑,然后计算其功率谱的重心来估计载频。为了克服瞬时自相关法分析PSK信号时抗噪性能不强和分析精度不高的缺点,采用了时域叠加瞬时自相关的方法。先用载频估计值抵消信号的相位偏移量,然后对时域叠加瞬时自相关的结果做FFT,取第1个峰值点对应的频率作为码速率的估计结果。对二相编码和四相编码的情况进行了计算机仿真,基于4片ADSP-TS101S芯片构成的雷达信号参数估计平台,对2PSK信号进行了硬件实验。实验结果表明,该算法可以在较低信噪比下有效地估计PSK信号的码速率。

To estimate the parameters of PSK signals, the symbol rate estimation of PSK signals and the hardware implementation were researched. The PSK＇s spectrum was smoothed and the barycenter of the power spectrum was computed to estimate the carrier frequency（CF）. The method of instantaneous autocorrelation had the disadvantages of weak noise resistant capability and low precision, so the method of instantaneous autocorrelation with time domain addition was adopted. The phase offset was counteracted by the estimated value of CF, FFT was made to instantaneous autocorrelation with time domain addition, and the frequency of the first peak was taken as the estimation of symbol rate. Computer simulations were done for 2 PSK and QPSK, and hardware experiment was done for 2PSK based on the platform of parameter estimation for radar signals with 4 ADSP-TS101Ss. The results show that the algorithm can estimate the symbol rate of PSK signals effectively in lower SNR.