Low Frequency Weak Magnetic Signal Processing Based On Stochastic Resonance

The detection and analysis of weak magnetic signals,especially low-frequency weak magnetic signals,are widely used in radar,sonar,communication,industrial measurement,mechanical system fault analysis and other fields.At present,weak magnetic signal is vulnerable to environmental interference.How to effectively eliminate noise interference and improve the signal-to-noise ratio of low-frequency weak magnetic signal has become the focus of researchers.Aiming at the problem of low-frequency weak magnetic signal detection and de-noising,this research builds a low-frequency weak magnetic signal acquisition platform,and uses the ensemble empirical mode decomposition(EEMD)and bistable stochastic resonance model to de-noising the signal,so as to improve the signal-to-noise ratio of low-frequency weak magnetic signal.Firstly,the low-frequency weak magnetic signal acquisition platform is built by using air-cooled spindle motor,acquisition coil,preamplifier circuit and oscilloscope.Then the EEMD algorithm is used to preprocess the nonlinear and unstable low-frequency weak magnetic signal.The effectiveness of the algorithm is verified by simulation and experimental analysis.Finally,a bistable stochastic resonance algorithm based on cuckoo algorithm and scale transformation is proposed to establish a bistable stochastic resonance model.Using the good global characteristics of cuckoo algorithm in the initial search,the parameters in stochastic resonance are optimized to form an adaptive variable scale frequency shift band-pass stochastic resonance algorithm to improve the signal-to-noise ratio of low-frequency weak magnetic signals.Through the simulation and actual test of low-frequency weak magnetic signals in different frequency bands,the processed signal frequency-domain waveform is smoother,and the signal-to-noise ratio is more than twice as high as the original,which proves the reliability of the bistable stochastic resonance algorithm based on cuckoo algorithm and scale transformation combined with optimization algorithm.