混沌背景下谐波信号的多域联合盲提取算法研究

发布时间：2018-06-18 08:08

本文选题：混沌信号 + 固定点算法　；参考：《黑龙江大学》2014年硕士论文

【摘要】：随着社会的不断进步,计算机的普遍应用和各种通信网络的建立,人们逐步走进一个信息爆炸的时代,因此对信息保密度的要求越来越高,保密通信领域应运而生。混沌信号凭借其随机性、对初始条件的敏感性、以及宽谱功率谱密度等优质特性,使混沌信号很难被破解,广泛被应用到保密通信中。本论文所研究的在混沌背景下提取谐波信号不仅可以作为混沌保密通信系统的保密性检验手段,对于分析、侦查对方信号提高混沌保密通信系统的自身安全性也具有重要意义。本论文以三种典型的混沌动力学系统为背景,首先利用典型盲源分离算法中的固定点算法和联合近似对角化法提取混沌背景中的谐波信号,并对比在不同混沌系统背景下的谐波信号分离和提取效果,通过实验仿真得出结论,对于不同混沌系统,利用同样的算法,谐波信号的提取效果却存在优劣之分；继而深入剖析三种混沌系统的时频域特性,通过分析混沌系统的频域特性,提出混沌系统的能量聚集带并研究了能量聚集带对谐波信号提取产生的影响；通过研究混沌系统的时域特性,提出了求解李亚普诺夫指数来动态捕捉混沌系统稳态点的方案；通过数据截短方案,设计出一种新颖的基于混沌系统稳态点捕捉的谐波信号盲提取算法,通过仿真实验,验证采用此算法呈现出更好的分离和提取效果。论文最后分析了谐波信号的幅度和频率间隔,对该算法的影响,证明了本论文算法的稳定性和有效性。
[Abstract]:With the development of society, the general application of computers and the establishment of various communication networks, people have gradually stepped into an era of information explosion, so the requirement of information security is becoming more and more high, and the field of secure communication emerges as the times require. Because of its randomness, sensitivity to initial conditions, and high quality characteristics such as wide spectrum power spectrum density, chaotic signals are difficult to be deciphered and widely used in secure communications. In this paper, the harmonic signal extraction in chaotic background can not only be used as a security test method of chaotic secure communication system, but also has important significance for analyzing the detection of the other signal to improve the security of chaotic secure communication system. In this paper, three typical chaotic dynamical systems are used as the background. Firstly, the fixed point algorithm and the joint approximate diagonalization method are used to extract the harmonic signals from the chaotic background. By comparing the results of harmonic signal separation and extraction in different chaotic systems, the experimental simulation results show that for different chaotic systems, using the same algorithm, there are advantages and disadvantages of harmonic signal extraction. Then the time-frequency characteristic of the three chaotic systems is deeply analyzed. By analyzing the frequency-domain characteristic of the chaotic system, the energy accumulation band of the chaotic system is proposed and the influence of the energy accumulation band on the harmonic signal extraction is studied. By studying the time-domain characteristics of chaotic system, a scheme of solving Lyapunov exponent to dynamically capture the steady-state point of chaotic system is proposed, and the scheme of data truncation is presented. A novel blind harmonic signal extraction algorithm based on steady state point capture of chaotic system is designed. The simulation results show that the proposed algorithm has a better separation and extraction effect. Finally, the amplitude and frequency interval of the harmonic signal are analyzed, and the influence of the algorithm on the algorithm is proved. The stability and effectiveness of the algorithm are proved.
【学位授予单位】：黑龙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：O415.5;TN918

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