Duffing混沌振子微弱信号检测方法研究

研究了采用Duffing混沌振子检测微弱正弦信号频率的可行性并分析了检测性能,提出了利用混沌振子输出方差极值对来检测微弱正弦信号的方法。首先根据混沌振子周期策动力与待测信号频率相等时,系统输出方差值最大这一性质,研究了采样频率对检测结果的影响。实验结果表明,通过增大采样频率并增加数据序列长度,在信噪比-45 dB时可以检测出信号。然后,将此性质应用于与周期策动力有随机相位差的正弦信号检测中,发现在二者频率接近或相等时,系统输出方差值发生跳变,出现一个极大值和一个极小值对,通过这一新的特性可以检测出与激励信号有相位差的信号频率。最后将此方法成功应用于调幅波的频率检测中。

Study on the method of chaotic oscillator in weak signal detection

The feasibility of using Duffing chaotic oscillator to detect the weak sinusoidal signal is testified and the performance is analyzed. The method of using the pair of extreme values of the system output variance to detect the weak signal is proposed. The influence of sampling frequency on the results is analyzed based on the theory that the output variance value of the system will reach a maximum when the signal frequency is equal to the reference frequency. Experiments have indicated that the weak signal will be detected in the lower signal to noise ratio SNR=-45 dB by increasing the sampling frequency and the length of the data sequence in the meanwhile. Moreover, the signal which has a random phase difference with the reference signal can also be detected based on the above theory, the experiments results have verified that the variance still has a dramatic change when the signal frequency is approximately equal to the reference frequency, and there appears a maximum value and a minimum value. This new property is successfully applied to measuring the frequency of amplitude modulated signal produced by the signal generator.