| Due to sensitive dependence on initial conditions, it is practically impossible to repeat the same signal generated by chaotic system. However, it has been shown that two chaotic systems (a drive and a response system) can exhibit synchronous chaotic behavior if adequately “coupled.”; In this dissertation, a more general framework for synchronization of chaotic systems is proposed. Instead of using the exact copy of the drive system as the response system, we make use of nonlinear state observer design methods in state reconstruction of chaotic systems. We show that synchronization of chaotic systems can be effectively achieved by using any of the proposed methods. The issue of robustness of synchronized chaotic oscillators with respect to noise is also addressed.; Unlike periodic carriers, chaotic signals are commonly characterized by quite broad power spectra. This property, together with sensitive dependence on initial conditions make chaotic systems attractive for application in secure communications since an information-bearing message can be hidden within a complicated structure of a chaotic carrier. Various estimator methods are applied to introduce a means to secure communications by chaotic masking and chaotic modulation, where the information signal is injected into the chaotic signal to be simultaneously transmitted to the receiver. |
