DSSS系统中快变化线性调频干扰抑制算法

直接序列扩频(DSSS)系统中用分数傅里叶变换可以抑制线性调频干扰等非平稳干扰,然而快变化线性调频干扰有可能在分数傅里叶域上呈现出多个尖峰,不利于干扰的检测.分析了线性调频干扰对DSSS系统的影响,提出了利用模糊变换和分数傅里叶变换结合抑制线性调频干扰的算法,通过模糊变换选择延迟时间估计调频斜率,然后在相应的分数傅里叶域滤除干扰,克服了分数傅里叶变换在估计调频斜率时可能出现的多尖峰问题.仿真表明,此算法可以有效估计并滤除DSSS中的线性调频干扰.

An Algorithm for Suppressing Quickly varying LFM Interference

In direct sequence spread spectrum(DSSS) system, Fractional Fourier Transform (F RFT) can be applied to suppress nonstationary interference such as Linear Frequency Modulation (LFM) interference. But quickly varying LFM interference may show man y pulses in the FRFT field, as worsens the ability of detecting LFM interference . This paper analyses the effects of LFM interference on DSSS system, and propos es an algorithm based on ambiguity transform (AT) and FRFT to suppress LFM inter ference. Modulation rate is estimated using AT and LFM interference is filtere d out in corresponding FRFT field. The question of many pulses is solved when th e modulation rate is estimated using FRFT.Simulation shows that the algorithm c an efficiently estimate the parameters of LFM interference and excise it.