Research On Weak Signal Detection Method Based On Duffing Oscillator

A weak signal is a useful signal with relatively small amplitude, and this kind of signal is usually overwhelmed by strong noise. The traditional weak signal detection method is mainly based on filtering and suppressing noise, such as narrowband filtering, wavelet analysis, sampling integral,correlation detection, etc., but these methods will cause damage to the useful signal and detect the signal to noise ratio threshold is relatively high.At present, the use of Duffing system for weak periodic signal sensitivity and arbitrary zero mean noise immunity characteristics, can achieve low signal to noise ratio of weak periodic signal detection.In this paper, the dynamic characteristics of the Duffing oscillator system and the influence of the noise on the system state are analyzed.Then, the method of the system threshold is analyzed. Based on the time threshold and phase trajectory method, the threshold of the system is determined by Lyapunov exponential method calculates the exact threshold of the system. Then, based on the shortcomings of the current detection method, the Duffing oscillator detection system is used to set a group simulation steps that can cover the frequency band of the signal to be measured, and realize the search for the low signal-to-noise ratio weak signal frequency Detection; Using the phase track observation method to measure the signal amplitude detection; Using the system in large scale periodic state when the maximum Lyapunov index and the driving signal to measure the total amplitude relationship, combined with the relationship between the amplitude and the phase of the driving,completed the initial phase effective detection of the measured signal.Finally, the parameters of the measured signal frequency, amplitude and phase are estimated, and the simulation experiments are carried out by matlab, which verifies the validity and accuracy of the method.