基于脉冲成形扩频信号伪码周期盲估计

针对基带扩频信号的频谱范围较宽，信号在带限的信道中传输时需要对信号进行带宽限制，从而会造成码间干扰和频谱泄露的问题，将基带扩频信号通过脉冲成形器后对其主要参数的抗截获性能进行了研究，并使用两次功率谱的方法对该类信号的伪码周期进行了估计。理论分析证明，做两次功率谱以后的信号以脉冲串的周期来扩展谱线，且信号主要能量将会聚集在一些类似于基带成形脉冲二次谱形状的尖锐脉冲处，通过测量这些尖锐脉冲间的间距即可以估计出基带扩频信号的伪码周期。计算机仿真结果证明，两次功率谱的方法可以在低信噪比的条件下实现对带脉冲成形基带扩频信号伪码周期的估计，且本文算法对伪码周期估计的正确率比文献1]算法约提高7dB左右。

Blind Period estimation of PN sequence based on pulse shaping of spectrum signal

The spectrum of the baseband spread spectrum signal has a wide frequency range, when the signal is transmitte the spectrum of the baseband spread spectrum signal has a wide frequency range, when the signal is transmitted in the band limited channel, the bandwidth of the signal needs to be limited, thereby causing intersymbol interference. Therefore, in order to reduce the inter-symbol crosstalk between baseband spread spectrum signals and their occupied bandwidth, this paper sdudy the main parameters of its low interception performance of the baseband spread spectrum signal after it passes through the pulse shaper. And pseudocode period has been estimated by using twice power spectrum. The theoretical analysis proves that the signal after twice power spectrum extends spectral line on the period of impulse sequence, and the main energy of the signal will gather in some sharpness similar to that of the quadratic spectrum of the baseband shaping pulse. The pseudo-code period of the baseband spread spectrum signal can be estimated by measuring the spacing between these sharp pulses. Computer simulation results show that the method of twice power spectrum can be used to estimate the pseudo-code period of pulse shaped spread baseband signal under low signal-to-noise ratio condition. And accuracy of the algorithm to estimate the pseudo-code period proposed in this paper improves approximately 7dB compared to the method without pulse shaping.