Study On Method Of Detect FOS Signal By Modified Chua's Circuit

In recent years, as the important content of the nonlinearity science, the chaos theory has got quite great progress in a lot of technology field. In this paper we modified the most representative Chua's circuit, and rebuilded it to a four step non-autonomous non-linear dynamic system. By a lot of simulations and circuit experiments, we have validated the feasibility that use this circuit practically in the detection of the FOS singal,and discussed some actual circs.The first part we explained the development history of the present weak signal dedection, the merit and present situation of time field processing method, chaos theory development course and application. And introduced several definitions about chaos and bifurcation, in order to lays the foundation for the behind theoretical analysis and the experiment.In the second part we enumerated some common detective ways and some discriminances of chaos phenomenon, and explained Melnikov's criterion amply.Based on the criterion we can understand conveniently weather the system's output estate was chaotic state, or stable periodic condition, we could also know accurately that weather the pending signal was the pure noise, or mix cyclical signal, and needn't to protract the simulation time blindly. Thus we could advance the veracity and the validity of the weak signal detective precision.At the third part, we expounded the elements by the chaos theory and chaos method. On the base of analysed the mathematic model of the Choa's circuit and the volt-ampere characteristic of the Choa's diode, we made the EWB simulation experiment and the circuital experiment to the dynamic property and the noise property of the modified Chua's circuit. The result validated elementary that the feasibility of the use of Chua's circuit actual apply to FOS, and detecting accuracy and the signal-to-noise are also achieve the request of the design.