Sduty On Methods Of Harmonic Parameter Estimation In Chaotic Noise Background Based On Chaotic Synchronization

In recent twenty years, lots of signals show chaotic character in nature and practical use, some of these signals are beneficial to us while some are harmful to us. In one case, target signal are merged in the background of chaotic noise; in other cases, in order to transmit signals more safety and reliable, we mix signals to be transmitted and chaotic signals to one. The difference between above two cases is that, the model of the chaotic signal is unknown in the first case while known in the second case. If the target signals are harmonic signals, we should detect the frequencies of harmonic signals in both of the two cases, which is based on the idea that chaotic signal should be removed first. In the first case, based on the priori knowledge that the mixed signals have chaotic characters, we usually use phase space reconstruction technology and nonlinear predictive methods to predict chaotic signals, and neural network methods are used often. In the second case, based on the priori knowledge that the model of chaotic signals is known, we usually use the way of synchronization of chaos to predict chaotic signals, and the theory support for the idea is that the chaotic synchronization system has good robustness. In this paper, we study on the method of harmonic parameter estimation in chaotic noise background based on chaotic synchronization. We first introduce current state of chaos theory and it's application in signal processing field, then we present the basic knowledge of chaos theory and chaotic synchronization. we analyze the robustness of chaotic synchronization system based on traditional theory of the stability of nonlinear disturbances systems, then we introduce contraction theory and apply it to design chaotic synchronization controller, and found it's convenient to solve some chaotic synchronization problems We design the chaotic synchronization controller of lorenz system and rossler system when the parameters of the model is known and unknown respectively, meanwhile, we analyze the robustness of chaotic synchronization system when they are perturbed, then we detect the frequency of harmonic signals using traditional spectral analysis method, the detection effect is in connection with the robustness of chaotic synchronization system. we do a lot of simulation experiments, these results manifest the robustness of chaotic synchronization system, more over ,these results prove that it is effective to detect the frequency of harmonic signals merged in the background of chaotic signals based on the idea of chaotic synchronization theory.