Synchronization Phenomena in Coupled Non-identical Chaotic Circuits

The last decades, the synchronization between coupled chaotic circuits has attracted the interest of the research community because it is a rich and multi-disciplinary phenomenon with broad range applications, such as in broadband communication systems, in secure communications and in cryptography. For this reason many coupling schemes between identical nonlinear circuits with chaotic behavior have been presented. However, the basic drawback of the majority of these schemes is the request the coupled circuits to be identical, due to the fact that in real world applications this is impossible. Motivated by the aforementioned inevitable feature of this class of circuits, which drives the systems out of synchronization, a unidirectional coupling scheme between non-identical, nonlinear circuits, is presented in this work. The circuit, which is used, realizes a four-dimensional modified Lorenz system, which is capable of producing chaotic and hyperchaotic attractors. Furthermore, the coupling scheme is designed by using Nonlinear Open Loop Controllers to target the synchronization state. The stability of synchronization is ensured by using Lyapunov function stability theory. Simulation results of the proposed coupling scheme by using SPICE are also presented to verify the feasibility of the proposed coupling scheme.