Abstract: In direct sequence spread spectrum communication system when the spreading gain is limited，the performance of the communication system will be impacted by the strong power of narrowband interference.In order to improve communication effectiveness，Phase-Inversion Symmetric Method（PISM） and Direct Sequence Spread Spectrum（DSSS） communication are combined，and Phase-inversion Symmetric-Direct Sequence Spread Spectrum Communication（PIS-DSSSC） system is established.The theoretical analysis and simulation experiment of narrow-band jamming suppression ability of PIS-SSC system are carried out.The simulation results show that PIS-SSC system has a good suppression effect for the narrowband interference；especially for the strong power of narrowband interference suppression，the suppression effect is particularly remarkable.

Key words: Phase-Inversion Symmetric Method（PISM）, Direct Sequence Spread Spectrum（DSSS） communication, Phase-
inversion Symmetric-Spread Spectrum Communication（PIS-DSSSC） system, narrow-band jamming

摘要： 在直接序列扩频通信系统的扩频增益受限时，强功率的窄带干扰对系统性能影响较大。为了提高系统的通信效果，将反相对称法和直接序列扩频通信相结合，建立了一种新的通信系统——反相对称-直扩通信系统，对系统的抗窄带干扰能力进行了理论分析和仿真研究。理论分析和Matlab仿真结果表明，反相对称-直扩通信系统对窄带干扰有很好的抑制作用，对强功率的窄带干扰的抑制效果尤为显著。

关键词: 反相对称法, 直接序列扩频通信, 反相对称-直扩通信系统, 窄带干扰