Design And Implementation Of Duffing Oscillator Communication System Based On FPGA

Chaotic motion is widely used in the field of communication because of its instability,long-term immeasurability,limited in a limited area,and the track never repeats.Because of its noise like characteristics,chaotic signal has a strong security.However,due to the problem that chaotic synchronization is difficult to achieve in coherent demodulation of the receiver,the error rate of the traditional communication method can not be achieved as a result,and the development of chaotic communication is relatively lagging behind.Chaotic communication focuses on theoretical research and has not been applied in engineering.Based on the current research results of chaos communication theory,this paper selects the Duffing oscillator with the characteristics of planar motion track,stable periodic orbit and low complexity as the core of the research,designs and realizes the quaternary signal chaos communication system based on Duffing oscillator.In this paper,a modulation algorithm based on amplitude is designed for Duffing oscillator,which has the characteristics of amplitude parameter sensitivity,motion immeasurability and noise like.The baseband information is loaded into the state of Duffing oscillator,and the chaotic state and periodic state of Duffing oscillator are used to represent the baseband symbol information.The signal has strong security.At the same time,in order to improve the efficiency of information transmission,the baseband symbol is selected as the quaternary Signal.When demodulating the signal,according to the different frequency component characteristics of Duffing oscillator in periodic state and chaotic state,a demodulating algorithm based on power spectrum is designed.This method does not need to realize chaos synchronization,and the algorithm is simpler and easier to realize.In order to better evaluate the performance of the communication system,this paper built a simulation model in the software MATLAB environment,and carried out a theoretical analysis of the experimental results,in the hardware using FPGA platform for verification.The transmitter module is designed with baseband code generation,serial to parallel conversion,Duffing oscillator modulation algorithm,orthogonal modulation and other modules.The receiver module is designed with orthogonal demodulation,decimation,spectrum analysis demodulation,bit synchronization,parallel to serial conversion and other modules.The test results show that the algorithm design is correct and the performance is good.The transmitter can send signals and the receiver can demodulate signals in real time.