Study Of Communication Jamming Technology Based On Nonlinear Theory

Communication jamming is a positive, aggressive behavior in communicationcountermeasures. In recent years, with the rapid development of communicationtechnology, communication jamming faces new challenges, and it is difficult to designappropriate jamming mode for different communication systems. But on the other hand,nonlinear science has developed rapidly and it brings new thought for communicationjamming. Based on the nonlinear science, a new chaotic jamming technology isproposed and the nonlinear of communication system is studied. The main researchtopics and the related new results are listed as follows：1．A new chaotic jamming technology is proposed based on the nonlinear science.This thesis introduces two different ways to produce chaotic jamming by discretechaotic map and continuous chaotic system. Then, this thesis simulates three kinds ofsignals including the white noise jamming, single-tone jamming, direct chaotic jammingand iterative chaotic jamming. At last, the time domain characteristics and frequencydomain characteristics are analyzed. The simulation results show that the direct chaoticjamming and the iterative chaotic jamming signals are fit for jamming communicationsystem.2. Performance of synchronization module of communication system under thejamming signals is studied. First, the principles of synchronization by phase lock loop(PLL) are introduced. Then, this thesis modules the synchronization module for QPSKmodem system and analyses the time of losing lock under white noise jamming,single-tone jamming, direct chaotic jamming and iterative chaotic jamming. Finally,several jamming modes which can effectively interfere the synchronization module areobtained by the simulation results.3. Performance of transparent transponder under the jamming signals is studied.First, this thesis analyses the nonlinear characteristics of transparent transponder, andmodules the limiter by nonlinear method. The power change of the limiter is deeplystudied. Then, this thesis simulates the limiter performance under different kinds ofjamming which mainly include white noise jamming, single-tone jamming, direct chaotic jamming and iterative chaotic jamming. The computer simulation results showthat some kinds of chaotic jamming signal can damage the limiter significantly. At last,in order to verify the theoretical derivation, an interference experiment is made in thelab. According to data analysis, the performance of transparent transponder underdifferent kinds of jamming signals is summarized.