针对单微粒散射光信号弱、脉宽窄的特性, 设计了一种低噪声宽动态范围光电检测电路。首先对单微粒散射光脉冲检测原理进行了分析; 然后根据散射光脉冲信号特征对检测电路进行了设计; 最后搭建了实验系统并对检测方法性能指标进行了评估。实验结果表明: 设计的电路带宽为1.5 kHz~1.2 MHz, 总输出噪声的均方根值为3.51 mV, 计算结果与实验结果基本一致, 误差为3.33%。该光电检测电路能够有效地对微弱的散射光信号实现低噪声放大, 为后续处理提供了稳定的信号。

Aiming at the characteristics of weak signal and narrow pulse width of the single particle scattering light, a photoelectric detection circuit with low noise and wide dynamic range was designed. Firstly, the principle of single particle scattering light pulse detection was analyzed. Then the detection circuit was designed according to the characteristic of scattering light pulse signal. At last, the experimental system was set up and the performance index of the proposed detection circuit was evaluated. The experimental result showed that the bandwidth of the circuit was 1.5 kHz~1.2 MHz and the total output noise was 3.51 mV. The calculated results were basically agreed with the experimental results, and the error was 3.33%. The photoelectric detection circuit can effectively amplify the weak scattering light signal with low noise and provide stable signals for the subsequent signal processing.