采集强干扰下微弱信号的APD电路系统研究

基于雪崩光电二极管反向偏压及其电容特性,利用时间同步原理,构建了一个用于回避强烈反射光信号,探测微弱回波信号的雪崩光电二极管探测系统.对雪崩光电二极管电容效应作出了分析,得出交流高压供电会使雪崩光电二极管产生干扰尖峰脉冲的结论.为了消除这个电容效应产生的尖峰干扰,提出了施加直流反向低压的方案,以达到减少雪崩光电二极管电容变化量的目的.通过实验数据验证了方法可行性.

APD Circuit System for Weak Signal Detection Under Strong Interference

To avoid the strong interference,by controlling the voltage of the avalanche photodiode,an avalanche photodiode (APD) detection system for weak signal is presented.An analysis of the capacitance effect of the APD was performed.It shows that the capacitance effect will lead to a sharp pulse which interferes the weak signal was obtained.In order to eliminate the effect,a new idea that to set low DC reverse voltage which reduces the capacitance change of the APD is proposed.The idea was testified experimentally.