Research On Nonlinear Stochastic Resonance Detection Method Of Weak Digital Modulation Signal

The traditional view is that noise is harmful to signal transmission,therefore,most of signal detection methods are mainly to suppress noise.However,the process of suppressing noise will inevitably impair useful signal.The emergence of stochastic resonance has changed,which can convert energy of partial noise to the useful signal and enhance the useful signal by cooperative effect between the three systems using noise,signal and nonlinear system.At the moment,the research on the methods of stochastic resonance signal detection are based on the periodic sinusoidal signal or binary baseband signal,while the research on the method of stochastic resonance detection of digital modulation signal is relatively scarce.This paper mainly focuses on the method of stochastic resonance detection of digital modulation signal to study,The main researchs are follows:Firstly,the basic principle of nonlinear stochastic resonance is elaborated,the classical adiabatic approximation theory and the three methods to achieve stochastic resonance in three kinds of large parameter are introduced,and the measure index of stochastic resonance system are given.The reason of stochastic resonance is explained by the analysis of the potential function of bistable stochastic resonance system.And for the system of Langevin equation,the specific numerical algorithm is presented.The simulation experiments are carried out with the sinusoidal signal and pulse amplitude modulation signal as the input of the stochastic resonance system.This suits show that the adjustment of noise parameters or system parameters can produce stochastic resonance and achieve optimal system output,which can effectively detect the weak input signal.Secondly,the bistable stochastic resonance extraction model of BPSK signal is constructed.For the input signal submerged under gaussian noise,we can use system parameter adjustment method to achieve stochastic resonance phenomenon,and thus get a good testing system output,and find that the input signal can be enhanced effectively by adjusting the system parameters,and there is an optimal stochastic resonance point.Then,the characteristics of alpha stable distribution is explored,and the alpha stable noise and BPSK signal as the input signal of the bistable stochastic resonance system,the stochastic resonance signal detection model under the interaction of the alpha stable noise and the BPSK signal is constructed.Using the forth-order Runge-Kutta algorithm for solving the system of equation,the system output SNR gain as the detection index,resonance output law of bistable system under the combined action of alpha stable noise index and system parameters are explored.Finally,the simulation results show that the stochastic resonance can be implemented by adjusting the system parameters and enhanced the input of BPSK signal.There exist the optimal values of the system parameters of a,b and the noise parameters,that the optimal values can make the enhancement effect of stochastic resonance is the best.Thus the BPSK signal can be detected from the noise.