光纤激光水听器的PGC实时全数字解调系统

PGC digital real-time demodulation system of fiber laser hydrophone

概述了基于麦克尔逊干涉仪的光纤激光水听器的相位载波零差法(PGC)调制解调原理,通过数学推导及仿真,分析了调制信号和混频信号的频差是导致全数字化解调结果错误的主要因素之一。针对该诱导因素提供了可行的解决方案,并实现了基于DSP的1 MHz采样频率下使用PGC方法的全数字实时解调系统。对低频水声波段800Hz水声信号进行解调,实验结果表明:解调信号波形良好。

The PGC demodulation principle of fiber laser hydrophone based on Michelson interferometer was introduced.Then,mathematical deductions and simulations were carried out through which to analyze the frequency difference between the modulation signal and the mixing frequency signal.The difference is one of the error-induced factors.To solve this problem,a resolution was provided for designing a digital real time demodulation system with sampling rate of 1 MHz based on DSP by using PGC method.An experiment was done on the demodulation of an acoustic signal with the frequency of 800 Hz.The result shows that the waveforms of demodulated acoustic signal are ideal.