Research On Some Chaotic Secure Communication Questions

This thesis is concerned with some problems of chaotic system and chaotic sychronization secure communication.Chaos is a outer complex behave of nonlinear definite system, produced by the system's internal random property, a non-random movement while it looks like random. The one of its basic characteristics is that the system is highly sensitive to original condition, that is to say, the system's output, with the time went by, assumes index increase because of the system's little difference of original condition, can't be accepted, it could not be used without being controlled.The study of chaotic control and chaotic secure communication has become a hotspot problem of info-sci field, many achievements have acquired, but it doesn't much too reach practical application phase. On the base of achieved research production, the following study aspects are carried through in this thesis:1) In allusion to Lorenz chaos circuit, the relation of circuit equation's parameters to elements' values is put forward, as a result, that whether the circuit engenders chaotic phenomenon can be easily estimated. With respect to the Chua's circuit, a simulated inductor is designed, Chua's circuit is also improved by means of simulated inductor, and then, it becomes very easy to make Chua circuit apply to practical engineering.2) In the field of chaos secure communication, chaos synchronization is a key technology. In view of drive-response Chua's circuit chaotic synchronization system, chaos synchronization self-maintenance is put forward in this thesis, it solves the present problem of how to stimulatingly transmit useful signal and chaos synchronization control signal in the same one channel, as a result, it establishes the groundwork of putting chaos into practical application of engineering and communication field.3) To theoretically analyze the distortion-frequency characteristic of Chua's circuit and discuss the chua circuit's design principle and chua signal's bandwidth estimation. Depend on its above, a tow-grade modulation chaos masking communication is put forward in order to improve demodulation signal's fidelity.4) A user's interface is designed in this paper. Utilizing the interface, all most aspects of chua's circuit, including circuit's parameters, initial conditions, eigenvalues, vector field, movement track, and so on, may be fully and directly reflected. On the one hand, it solves existing situation of no-directly perceived nature and complexity in researching all aspects of Chua's circuit; on the other hand, investigators can still more conveniently study the circuit. As a whole, the software endows with application and extension value.