基于类洛伦茨系统的微弱信号检测方法研究及其电路实现

发布时间：2019-02-09 20:43

【摘要】：对于传统微弱信号检测方法，输入信号信噪比难以降低，受到一定限制。而基于混沌理论检测微弱信号的方法弥补了这一缺陷，能够达到极低的信噪比，提高了检测精度。本文针对此展开了研究。论文在研究混沌理论基础之上，设计了微弱信号检测系统，通过对系统建模、仿真、实际电路的设计，验证了利用混沌理论检测微弱信号的有效性。在对混沌基本特点分析研究基础上，给出了类洛伦茨系统的具体模型，并做详细分析。提出双参数控制的混沌控制方法，可将系统控制在所期待的周期轨道内。此方法避免计算精确的激励信号幅值，提高工作效率，，可控性强。根据特定混沌系统对于参数敏感性而对噪声免疫的特性，利用双参数控制方法，构造了基于类Lorenz（洛伦茨）系统的微弱信号检测模型，理论分析验证了该检测系统具有检测中低频微弱周期信号的特性。通过具体的仿真实验，成功实现了噪声背景下微弱信号的检测，效果显著，达到较低信噪比，表明利用类Lorenz系统进行微弱信号检测是可行的。针对目前混沌系统检测微弱信号尚停留在仿真的现状下，为验证混沌检测方法的实际应用的有效性，本文搭建了混沌检测实验电路。根据电路特性的分析，组织架构具体实现微弱信号检测的原理框图,采用模块化设计，利用DSP数字信号处理技术，产生周期激励信号，幅值和频率可灵活控制。然后利用运算放大器以及电阻电容等元器件做出实际检测电路。完成微弱信号混沌检测实际电路的搭建，通过示波器中判断相轨迹的明显变化来检测微弱信号。本文创新之处在于，提出双参数控制法控制混沌，并将此方法应用于基于类Lorenz系统的微弱信号检测中。matlab仿真实验以及具体实际电路实验同时验证了方法的有效性。同时分析当前混沌系统检测微弱信号对具体的电路实现上还没有充分应用的情况下，本文对所建立的类Lorenz混沌检测系统做出了具体的电路实验，电路实验分析结果与理论分析达到一致性,为实际工程应用检测微弱信号提供了一个简单有效的检测装置，具有良好应用前景，对微弱信号检测进行了有意义的探索。
[Abstract]:For the traditional weak signal detection method, the SNR of the input signal is difficult to reduce and is limited to some extent. The method of detecting weak signal based on chaos theory makes up for this defect, and can achieve extremely low signal-to-noise ratio (SNR) and improve the accuracy of detection. In this paper, the research is carried out. Based on the study of chaos theory, a weak signal detection system is designed in this paper. The effectiveness of using chaos theory to detect weak signal is verified by modeling, simulation and practical circuit design. On the basis of analyzing and studying the basic characteristics of chaos, the concrete model of Lorenz-like system is given and analyzed in detail. A two-parameter chaos control method is proposed, which can control the system in the desired periodic orbit. This method avoids calculating the exact amplitude of excitation signal and improves the working efficiency and controllability. According to the characteristic that a particular chaotic system is immune to noise due to its sensitivity to parameters, a weak signal detection model based on Lorenz (Lorentz)-like system is constructed by using the two-parameter control method. The theoretical analysis verifies that the detection system has the characteristic of detecting low frequency weak periodic signal. Through the concrete simulation experiment, the weak signal detection under the background of noise is successfully realized, the effect is remarkable and the signal-to-noise ratio is low, which indicates that it is feasible to use the similar Lorenz system to detect the weak signal. In order to verify the effectiveness of the practical application of the chaotic detection method, a chaotic detection experimental circuit is built in this paper in view of the fact that the weak signal detection in the chaotic system is still in the state of simulation. According to the analysis of the circuit characteristics, the principle block diagram of the organization structure to realize the weak signal detection is presented, the modular design is adopted, and the DSP digital signal processing technology is used to generate the periodic excitation signal. The amplitude and frequency can be controlled flexibly. Then the operational amplifier and resistive capacitance and other components to make the actual detection circuit. The actual circuit of weak signal chaotic detection is built, and the weak signal is detected by judging the obvious change of phase locus in oscilloscope. The innovation of this paper is that the two-parameter control method is proposed to control chaos, and this method is applied to weak signal detection based on Lorenz system. The effectiveness of the method is verified by the matlab simulation experiment and the actual circuit experiment at the same time. At the same time, under the condition that the weak signal detection in the current chaotic system has not been fully applied to the realization of the specific circuit, this paper makes a concrete circuit experiment on the Lorenz like chaotic detection system. The experimental results of the circuit are consistent with the theoretical analysis, which provides a simple and effective detection device for the practical engineering application of weak signal detection. It has a good application prospect, and makes a meaningful exploration for the weak signal detection.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.23

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