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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。
The feasibility of using Duffing chaos oscillator to detect the frequency of weak sinusoidal signal is studied and the detection performance is analyzed. A method to detect the weak sinusoidal signal by using the output of the extremum of variance of chaotic oscillator is proposed. First of all, according to the chaotic vibrator periodic motivation and the signal frequency to be equal, the system outputs the maximum variance of the nature of the study of the sampling frequency of the test results. Experimental results show that by increasing the sampling frequency and increasing the data sequence length, the signal can be detected at a signal-to-noise ratio of -45 dB. Then, this property is applied to the detection of sinusoidal signals with random phase difference from the periodic power. It is found that when the two frequencies are close to or equal to each other, the system output variance jumps to a maximum value and a minimum value Right, through this new feature can detect the phase difference with the excitation signal signal frequency. Finally, this method is successfully applied to the amplitude modulation wave frequency detection.