The narrowband interference suppression technique based on threshold detection in Direct Sequence Spread Spectrum (DSSS) communication system is discussed. The overlap-add algorithm is introduced to reduce the distortion of the signal. An improved adaptive threshold algorithm called normalization threshold interference detecting and suppressing algorithm is employed. After amplifying the envelope amplitude of the signal logarithmically and then making it normalized, a normalization threshold is found. Then the magnitude of the spectral lines which exceeds the threshold is reduced to the level of magnitude of noise spectral lines. Analysis and simulation show that the method can effectively suppress the narrowband interference in DSSS system.%针对直扩通信系统中基于门限检测的窄带干扰抑制的关键技术,引入重叠加窗方法,克服了由加窗带来的信号失真.并且提出了一种改进的自适应门限算法——归一化门限干扰检测处理算法.算法是将接收信号的包络经对数放大,归一化处理后得到一种归一化门限,然后将高于门限的谱线幅度抑制到与噪声相近的程度.分析和仿真表明,算法有较强的自适应能力,能有效抑制直扩系统中的窄带干扰.
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