采用Duffing振子和S变换的微弱BPSK信号盲检测研究

Blind Detection of Weak BPSK Signal by Using Duffing Oscillators and S Transform

针对强噪声中微弱BPSK信号的盲检测问题,论文从周期信号入手,指出相差固定时由于输入信号与Duffing系统内置信号存在频差,将导致系统进入周期性混沌状态。对BPSK信号,由于信号本身相位的变化,Duffing系统相轨迹演化将进入间歇性混沌状态。论文通过采用时序图法和S变换提取时序输出包络来判断Duffing系统间歇性混沌状态,分析了方程控守频带范围,并建立正相振子和反相振子检测方程,最后提出了基于Duffing振子和S变换的微弱BPSK信号盲检测模型。仿真实验结果表明,在信噪比大于-40 d B时,可以稳定实现微弱BPSK信号的盲检测。

The Duffing system will be in periodic chaos state by the influence of the frequency difference and fixed phase difference between periodic signal and forcing signal of Duffing system. The intermittent chaos state will appear due to the phase changing of BPSK signal. The weak BPSK signal blind detection model is proposed by using the sequence chart meth- od, extracting the envelope of the sequence output with S transform, determining the working bandwidth of the detection equation, and building of the normal and reverse phase oscillator detection equations. Simulation result shows the detection of weak BPSK signal will be realized when SNR is greater than -40 dB.