The Research Of Stochastic Resonance Enhanced Signal-to-Noise Ratio Gain

The mechanism of stochastic resonance (SR) is the synergistic effect between input signal, noise, and the nonlinear system. With the increasing of noise and when it reaches a specified value, the output signal-to-noise ratio (SNR) will achieve a peak, at this time the output can effectively reflect the information of a input. In this paper, we focus on the study of stochastic resonance enhanced SNR gain and of wheather the SNR gain can exceed unity in different SR models, with the help of noise rather than to suppress it. Improving SNR has great importance in signal processing, especially in the application of tweak signal detection, mechanical fault diagnosis, and radar signal localization. In recent years, more and more attentions has been paied to stochastic resonance method enhanced SNR gain.In this paper, we study stochastic resonance method enhanced SNR gain mainly from two aspects. It has been proved that within the regime of the validity of linear response theory, the SNR gain cannot exceed unity for a nonlinear system such as a bistable potential driven by a sinusoidal signal and Gaussian white noise. However, beyond regimes where linear response theory is applied, SNR gain can in fact exceed unity with an impulse input signal in bisatable system or static nonlinearities. Because of the application of sinusoidal signal is more wider, wheather SNR gain can exceed unity for a parallel array driven by a noisy input sine wave has beed studied in this paper. No matter the array unit is bistable elements or static nonlinearities, the SNR gain can exceed unity by changing the array size, adding some noise to the input signal and adjusting the array noise. The influence of band-limited noise on SNR gain in parallel array of nonlinearities has also been studied in this paper. Because of the input noise is band-limited, the SNR gain of the system has been greatly improved and can exceed unity in the parallel of two state quantizer and linear saturating system. Moreover, the band-limited input noise has a better improvement of the SNR gain comparing to the input Gauss white noise. This is because the characteristic of static nonlinearity itself. At last, the influence of changing bandwidth of band-limited noise on SNR gain has been discussed in this paper.