New chaotic systems: Electronic circuit realizations, synchronization and secure communication applications

Key Words: Chaos, Chaotic Systems, Strange Attractor, Chaotic Circuits, Synchronization, Chaotic Masking, Secure Communication Chaos and chaotic systems have many fields of applications. One of the popular practical application is secure communication. Chaotic signals depend very sensitively on initial conditions, have unpredictable features and noise like wideband spread spectrum. So, it can be used in various communication applications because of their features of masking and immunizing information against noise. Chaos-based secure communication systems have been alternative of the standard spread-spectrum systems, since they are able to spread the spectrum of the information signals and simultaneously encrypt the information signals with chaotic circuitry which is simple and inexpensive. In secure communication field, like Lorenz, Chua, Rossler, Duffing etc., classical systems are widely used. This thesis` aims are; finding and introducing new chaotic systems which could be used alternatively to classical chaotic systems; designing their electronic circuits, their synchronization circuits using Pecora-Carroll method, their chaotic masking communication circuits, and showing that these chaotic systems could be used in secure communication area. Towards these aims, firstly chaotic systems from different science disciplines were investigated. From these investigated systems, Diffussionless Lorenz, Rikitake, Rucklidge, Arneodo and Hoover(Sprott94A) systems were choosen. These chaotic systems are topologicaly simple but their dynamical behaviours are very rich and their synchronization and secure communication applications were not seen in literature. Using Matlab-Simulink and Orcad-Pspice programs, their modelings, electronic circuit implementations, synchronization and secure communication applications were realized, both numerically and as electronic circuit, respectively. Also, by performing simulations and researches using computer programs, new chaotic systems which didn?t exist in any science disciplines, were discovered. Seven of these were introduced. Using Matlab-Simulink and Orcad-Pspice programs, seventh system?s modeling, electronic circuit implementation, synchronization and secure communication application were realized, both numerically and as electronic circuit, respectively. Furthermore, experimental electronic circuits of the newly discovered chaotic G system, and Rikitake system were implemented and their oscilloscope outputs were given. Results obtained in this study have been discussed and evaluated in the last chapter.