Study On Theory And Experiment Of Noise Nonlinear Effect

Appropriate noise can improve the output signal-to-noise ratio(SNR) of systems under nonlinear conditions, there is noise nonlinear effect, and the intensity of effect is associated with the specific forms of nonlinear. From the point of enhancing noise nonlinear effect, the strength of noise effect of different nonlinear systems is analyzed, and a symmetric parabolic potential function is proposed, and the mechanism of enhancing noise effect is revealed. The kramers escape rate and output SNR of symmetric parabolic system are derived theoretically. Numerical simulation and experimental research results show that the noise nonlinear effect in symmetric parabolic system is more intenser, which can applied to detect the real weak vortex signals and bearing fault signals.Noise nonlinear effect generated by interaction of signal and noise and nonlinear systems. The particles jump between two potential wells in systems with the frequency of the signal under the synergy. The transition movement of particles is not only associated with the kramers escape rate of systems, but also related to particles movement in a single well. On the one hand, the higher kramers escape rate is, the faster the particles jump, the more sensitive the system is to noise, which makes it easier to stimulate the low-energy of noise, increase the output SNR, and enhance noise nonlinear effect. On the other hand, the smaller of system inherent angular frequency is decided by potential field force and the larger motion amplitude of particles is in a single well, the easier noise nonlinear effect is to be enhanced.The output characteristics of symmetric parabolic system are analyzed by numerical simulation and experiment, and power spectrum and SNR are used to measure noise nonlinear effect. The simulational and experimental results show that the noise effect enhanced in symmetric parabolic system can extract periodic signals overwhelmed by noise effectively, which is basically identical with theoretical analysis.Finally, the enhancement of noise nonlinear effect is used to detect the real weak signals, and the detection results of real weak vortex signals and bearing fault signals indicate that the noise effect enhanced in symmetric parabolic system can effectively improve the power spectrum value of the characteristic frequency of weak signals, which can obtain the characteristic frequency.