Study on the method of chaotic oscillator in weak signal detection

Abstract

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.