摘要
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。
In direct sequence spread spectrum（DSSS） system, Fractional Fourier Transform （FRFT） can be applied to suppress nonstationary interference such as Linear Frequency Modulation （LFM） interference. But quickly-varying LFM interference may show many 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 proposes an algorithm based on ambiguity transform （AT） and FRFT to suppress LFM interference. Modulation rate is estimated using AT and LFM interference is filtered out in corresponding FRFT field. The question of many pulses is solved when the modulation rate is estimated using FRFr. Simulation shows that the algorithm can efficiently estimate the parameters of LFM interference and excise it.
出处
《电讯技术》
北大核心
2010年第4期45-50,共6页
Telecommunication Engineering
基金
江苏省自然科学基金资助项目(BK2009057)~~
关键词
直接序列扩频
线性调频
干扰抑制
模糊变换
分数傅里叶变换
direct sequence spread spectrum（ DSSS）
linear frequency modulation（ LFM）
interference suppression
ambiguity transform
fractional Fourier transform（FRFT）
