Analysis of internal frequency's influence on blind detection of weak PSK signal by using duffing oscillator

Abstract

There are transition zones in the transition between the chaotic and periodic state in the intermittent chaos state of the blind signal detection by using Duffing oscillator. The relationship expression between transition zone time length and internal frequency of Duffing system is deduced; and the conclusion that higher internal frequency leads to shorter transition zone time length is given. The simulation experiment gives the time-frequency response curve. Besides, the equation of output amplitude, as dependent variable, and internal frequency, as argument, is deduced while Duffing system is in periodic state. The simulation experiment gives the amplitude-frequency response curve and shows that the best weak signal detection performance can be gotten when the internal frequency is equal to 0.6rad/s. Finally, the paper combines the scale transformation method and detection array, uses S transform to extract the envelope of Duffing system output, builds the blind detection model of weak PSK signal through analysis of the choosing principle of internal frequency and working bandwidth of Duffing system. The simulation experiment results show the efficiency of the blind detection model.