【作者】 卢艳；

【导师】 杨万全；

【作者基本信息】 四川大学 ， 通信与信息系统， 2003， 硕士

【摘要】 在通信尤其是通信对抗中，信息信号可能受到一类很强的具有非平稳、自相似和长程相关等特性的l/f类分形噪声的干扰。对于l/f噪声，在没有有效的白化滤波方案前只能将其当成白噪声处理，这样做的结果是使匹配滤波器的性能恶化。因此针对l/f类分形噪声设计和实现一种白化滤波器在信号检测中具有重要意义。另一方面，同步在采用“模-数-模”方法实现的模拟信号置乱加密通信中非常重要，必须在信息信号中加同步头信号。本文属于应用基础研究，其目的是研究l/f强噪声干扰条件下的信号同步技术，需要设计一种适合于信道特性的同步头信号并在强l/f噪声中进行弱同步信号检测。本文利用分形调制设计一段分形信号作为同步头信号，并在接收端利用小波变换对l/f类分形噪声的近似白化作用，设计一种白化滤波器，先对接收信号进行白化滤波，消除l/f噪声间的相关性，再采用相关器进行信号检测。另一方面，针对低信噪比情况下的弱信号检测问题，利用小波变换在时间、频率上有局部化信号的能力，设计了一种对分形信号进行小波变换和三重自相关处理，由相关函数的峰值对目标信号进行检测的信号检测方法。模拟结果表明这些方法能够有效地抑制噪声，实现目标信号检测和分析。更多还原

【Abstract】 In communications, especially in communication countermeasure, the information signals may be contaminated by the strong 1/f family of fractal noise with nonstationarityi self-similarity and long-term correlation. The 1/f noise is often treated as white noise in the past due to lack of effectively whitened filter and it makes the performance of matched filter worse. Thus designing and implementing a whitened filter against 1/f noise are significant. On the other side, synchronization in "analog-digital-analog" scramble communications is very important, and the synchronizing signal must be inserted into information signals. This dissertation belongs to an application fundamental research. The purpose is developing the signal synchronizing technique under the serious interference with 1/f family of fractal noise. A good idea is presented to generate a segment of fractal signals as the synchronizing signal in the sender. In the receiver, we designed a whitened filter to transform the 1/f-type fractal noise into whitened noise in order to remove the correlation of 1/f noise before defecting the signal. On the other hand, to detect the weak signal with lower SNR, a method is presented. The fractal signal is dealt with wavelet transform and triple correlation processing. The target signal is detected by correlation peak value. The result of simulation shows that these methods can effectively restrain jamming and achieve the detection and analysis of the target signal.更多还原