通过半导体激光照射采样气体,利用光电检测电路检测前向散射光强,并通过滤波电路、真值转换电路以及后置放大电路,最终将信号进行采样送入微处理器中处理。通过对信号处理电路的各个模块进行动态特性分析,从而找出对系统影响最大的模块部分并提出改进。结果表明,光电检测电路的动态特性对系统的影响最为显著,通过适当减小负载电阻,可有效改善电路的线性动态范围。 Through the semiconductor laser irradiation sampling gas, the use of photoelectric detection circuit detects the forward scattered light intensity, and through the filter circuit, true value conversion circuit and the post-amplifier circuit, and ultimately the signal is sampled into the microprocessor processing. By analyzing the dynamic characteristics of each module of the signal processing circuit, the part of the module that has the most influence on the system is found out and the improvement is proposed. The results show that the dynamic characteristics of the photodetecting circuit have the most significant impact on the system. By properly reducing the load resistance, the linear dynamic range of the circuit can be effectively improved.