Chen Keyu

Application of stochastic resonance technology in underwater acoustic weak signal detection

The high frequency Chirp signal in underwater acoustic communication usually submerged in various noise produced by ocean waves, ships, etc. In this paper, based on the principle of stochastic resonance for weak signal detection, the extraction and energy enhancement of high frequency weak signal are achieved by using bistable stochastic resonance system. The genetic algorithm is additionally used to adaptively select the system parameters. Finally, the principle is verified to be correct and feasible with spectrum chart and FRFT through simulation and experiments which provides a new analysis method and design guidance for the enhancement and detection of underwater acoustic weak signal.

Chirp FSK based on FRFT for underwater acoustic communication

Chirp spread spectrum has poorly rate of transmission in shallow water acoustic channel because of its channel parameters in the random changes. This paper proposes a novel chirp spread spectrum modulation system based on the explicit relationship between fractional Fourier transform (FRFT) properties of Chirp-FSK signals and their parameters (Chirprate and central-frequency). The system is easy to control parameters and gives a trade-off between BER and rate of transmission by modulation parameters adjusting. The paper proposed spread spectrum communication system based on Chirp signal has good anti-noise and anti-multipath.