混沌信号谱密度分布约束方法研究

发布时间：2018-04-29 00:28

本文选题：混沌信号 + 非线性项　；参考：《沈阳工业大学》2017年硕士论文

【摘要】：随着信息技术的飞速发展,通信系统的信息安全性问题日渐突出。混沌信号的宽频谱、类随机的特性,是其可用于通信领域信息加密的重要因素。而混沌信号功率谱分布不理想,无法利用混沌信号作为通信载波实现信号的无线传输,是目前制约混沌信号在无线通信领域发展的重要原因之一。研究影响混沌信号功率谱分布的因素,找出可以获得特定功率谱分布的混沌信号的设计方法,对提高混沌通信系统的性能及可实现性具有重大意义。首先,本文对Lorenz混沌系统、Lü混沌系统、Xü混沌系统、Zhou混沌系统这四种现有混沌系统的特性进行研究分析。通过对比每个系统的动力学微分方程和系统运动状态,分析不同的参数和非线性项的结构对混沌吸引子、吸引区域和信号功率谱分布的影响,进而得出系统的混沌吸引区域和信号的功率谱分布的内在联系。其次,根据不同的影响因素,找出对应的可以改变混沌信号功率谱分布的方法,利用参数法、非线性约束法、参数非线性约束法这三种方法在现有的混沌系统基础上设计出含参数的新混沌系统。通过理论分析确定新系统中参数的取值范围并进行数值仿真,采用直接观察法、李亚谱诺夫(Lyapunov)指数法和庞加莱(Poincaré)截面法等方法判定新系统的混沌特性。从实验结果中得出,混沌系统的状态变量被限定在一个圆环中运动时,其信号的功率谱分布在一定频率范围内。然后,从实验结果和实际应用方面,对比分析三种方法所存在的优缺点。最后,根据混沌系统的吸引区域与信号功率谱分布的关系,以叠加原理为思路,将一个混沌系统和一个二维圆系统相叠加,调整参数得到特定功率谱分布的混沌信号,验证了该方法的可行性。
[Abstract]:With the rapid development of information technology, the information security of communication system is becoming more and more serious. The wide-band spectrum of chaotic signals, which is similar to random, is an important factor that can be used in information encryption in the field of communication. However, the power spectrum distribution of chaotic signals is not ideal, so it is impossible to use chaotic signals as communication carriers to realize wireless transmission of signals, which is one of the important reasons that restrict the development of chaotic signals in the field of wireless communication. It is of great significance to improve the performance and realizability of chaotic communication system by studying the factors affecting the power spectrum distribution of chaotic signal and finding out the design method of chaotic signal which can obtain the specific power spectrum distribution. Firstly, this paper studies and analyses the characteristics of four kinds of chaotic systems, namely, Lorenz chaotic system, L 眉 chaotic system and X 眉 chaotic system. By comparing the dynamic differential equations and the motion states of each system, the effects of different parameters and the structure of nonlinear terms on the chaotic attractor, the region of attraction and the distribution of the power spectrum of the signal are analyzed. The relationship between the chaotic attraction region of the system and the power spectrum distribution of the signal is obtained. Secondly, according to the different influence factors, we find out the corresponding method which can change the power spectrum distribution of chaotic signal, using parameter method, nonlinear constraint method, The parametric nonlinear constraint method is used to design a new chaotic system with parameters based on the existing chaotic systems. The range of parameters in the new system is determined by theoretical analysis and numerical simulation. The chaotic characteristics of the new system are determined by direct observation method, Li Ya Lyapunov-index method and Poincar 茅 section method. It is shown from the experimental results that when the state variables of the chaotic system are confined to a circle, the power spectrum of the signal is distributed in a certain frequency range. Then, the advantages and disadvantages of the three methods are compared and analyzed from the experimental results and practical applications. Finally, according to the relation between the attraction region of chaotic system and the distribution of signal power spectrum, a chaotic system and a two-dimensional circular system are superimposed on the principle of superposition, and the chaotic signals with specific power spectrum distribution are obtained by adjusting the parameters. The feasibility of the method is verified.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O415.5

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