A modulated method based on stochastic resonance is put forward to detect the weak signals in rather broad frequency range

according to the characteristic of stochastic resonance produced in rather low frequency range in nonlinear bistable system.The theory analysis and experiment results show that the energy and SNR of the output signal modulated synergetic effect are both improved evidently

and the ability of detecting weak signals with strong noise is enhanced.This method can be adapted to develop the information resources of nonlinear bistable system within low frequency range.