光纤水听器时分复用检测电路带宽与串扰分析

The Bandwidth and Crosstalk Analysis of Detection Circuit in Time-division Multiplexing of Fiber-optic Hydrophone

在光纤水听器时分复用系统中,需要设计高增益,大带宽的信号检测电路。为了减小系统的噪声同时抑制通道间串扰,必须选择合适的电路带宽。本文分析了待检测信号带宽与脉冲形状的关系,以及电路串扰率与电路带宽、脉冲宽度、通道间延时的关系,给出了电路串扰率的解析表达式,得到了电路串扰带来的解调信号误差的表达式,分析表明电路串扰导致的解调信号误差的幅度与电路串扰率成正比,与前一通道施加的声信号的幅度的贝塞尔函数成正比,最后给出了与理论分析相符的实验结果。

In the time-division multiplexing fiber-optic hydrophone system,it is desired to design the signal detection circuit with large gain and bandwidth.In order to reduce the system noise while suppressing crosstalk between channels,you must select the appropriate circuit bandwidth.This paper analyzes the relationship between the bandwidth and the pulse shape of the signal to be detected and the relationship among circuit bandwidth,pulse width,channel interval,and circuit crosstalk ratio,and gives the analytical expression of the crosstalk ratio.Formulae of demodulated signal error caused by circuit crosstalk are derived,and the result is that the amplitude of the demodulated signal error is proportional to the circuit crosstalk ratio and the Bessel function of the amplitude of the acoustic signal added to the previous channel.The experimental results are consistent with the theoretical analysis.