直扩PSK中频数字化相关接收的设计与实现

Design and Implementation of PSK Digital Direct Sequence Spread-Spectrum Correlator Receiver in Intermediate Frequency

讨论并设计了一种PSK直序扩频数字相关解调系统.使用正交检测法进行相干解调,并使用一种改进的数字相关器进行解扩.分析及实验结果表明,低信噪比情况下能够正确解码,免去了最难解决的PN码同步单元,并为位同步的提取带来了极大的方便;与一般数字相关器相比,能有效克服调制载波与本地载波相位误差的影响,改善抗干扰性能.

A PSK spread spectrum system that uses the digital correlator is explored and designed. It uses orthogonal detection method for coherent demodulation; and uses an improved digital correlator for de-spread. The analysis and experiment results show that the correlator can decode correctly under the low signal-noise ratio（SNR） condition; and avoid the synchronization unit of PN code, which is hardly possible to deal with in the general spread spectrum system, and make it easy to pick up the bit synchronization. Compared with the common digital correlator, the application of improved correlator can effectively overcome the carrier modulation with the local carrier phase error and mitigate interference.