The application relates to a bistable SR
system and a low
signal-to-
noise ratio multi-
frequency sound signal detection device and method. By introducing an
optical fiber device, the closed-loop regulation of the
optical fiber grating is utilized to realize the random
resonance phenomenon based on the
bistability, and the low
signal-to-
noise ratio signal can be effectively extracted under the strong
noise background. Secondly, by introducing a
carrier signal, the difference frequency signal is obtained by mixing with the external signal, and the multi-frequency signal sensing is realized under the premise of fixing the detection range of the difference frequency signal. In addition, by introducing the array structure of the
optical fiber hydrophone, the spatial
gain is formed, and the high-sensitivity detection effect can be realized. Finally, the frequency distribution and the relative signal-to-noise ratio intensity size distribution of the obtained target sound signal can be used as the input of the neural
network model, the intelligent identification of the low signal-to-noise ratio target sound target is realized, and the detection and early warning of the
underwater target can be maximally realized.