为了解决光电检测系统检测微弱光信号时的噪声问题，通过建立等效电路模型，推导出了光电检测电路输出信噪比公式并分析了影响系统噪声性能的关键因素。设计了一种可探测微弱光信号、具有宽动态范围和自动换档功能的光电检测系统。实验结果表明，该系统可对微弱光信号进行精确探测。

In order to solve the noise problems of the photoelectric detection system in detecting weak optical signals, this paper designs a photoelectric detection system with a wide dynamic range and automatic shift functions by establishing equivalent circuit models, deriving the output signal-to-noise ratio formula of photoelectric detection circuit, and analyzing the key factors affecting the system noise performance. The experimental results show that this system can detect weak optical signals accurately.