| Nowadays, with the development of communication technology, information privacy is being taken more and more attention by people. While the modern communication technology has been complete, but there are also possibilities to be interpreted. And chaotic signal has the characteristics of ergodicity, the aperiodicity, the continuous spectrum of bandwidth, like-noise, so encryption signal encrypted by chaotic signal will be decoded hardly. Chaos signal has the characteristic of encrypting signal, so this characteristic is suitable for secret communication. In this thesis, several kinds of chaos systems and its synchronization control has been researched, and then the hardware of secure communication has been completed. The main research work in this paper has three parts as follow:In this paper, firstly, the three common chaotic systems which include Chua's circuits, Lorenz system and Chen system have been studied, and then chaos systems dynamics characteristic and the circuit structure have been analyzed. The three kinds of chaotic systems have been simulated by Matlab and Multisim, and through the observation of signal phase diagram, the chaotic attractors have been obtained through. Secondly, the chaos synchronization control has been studied based on the three circuits, and then the single variable feedback control has been designed in Chua's circuit, which means that use the single variable coupling to make the system to achieve synchronization. And then two kinds of different coupling control circuits have been designed. Adaptive control of Chen system was designed, which make the chaos circuit reached synchronization, and then specific circuit controller has been given. Finally, in this paper, the chaotic synchronization has been applied in secret communication. Using active simulation inductance to replace inductance in Chua's circuits, and the Chua's circuits has been improved. Used Chua's circuits'chaos signal, chaos masking audio secure communication has proceeded. For chaos in secret communication provides the basis for the practical application.In this paper, the several synchronic controller circuit which has been designed can make the two systems reach synchronization, but the two synchronic systems request the parameters strictly, also the adaptive control, which is the most advantages apply in secure communications. In the realistic circuits, the performance synchronization would be weakened, due to the different parameters between driving systems and corresponding systems. The result of the reasons is that the restore signal exist error, and this is the problem would been solved in the future. |
PDF Full Text Request