TDLAS技术调制参量的优化及实验研究

Optimization and experimental research on modulation parameters of TDLAS technology

为了研究激光调制参量对二次谐波信号峰值、信噪比、峰宽、对称性以及信号完整性的影响,基于硬件实验系统与Simulink仿真模型进行分析,验证了理论模拟结果与此硬件系统下信号变化趋势的一致性,同时确定了CO_(2)检测系统的最佳调制参量。通过实验系统对不同体积分数的CO_(2)在1432.04nm处的吸收光谱进行了测量,建立主吸收峰处信号强度与不同体积分数CO_(2)的反演模型,分析了系统性能及测量精度。结果表明,线性拟合系数R^(2)=0.9998,气体体积分数反演最大相对误差为0.7333%,系统检测限为0.0074%;通过调制参量的优化选择可以获得较为理想的二次谐波信号,从而实现待测气体体积分数的精确反演。该研究为检测系统中调制参量的优化提供了重要参考,为系统测量精度的改善提供了指导。

In order to study the effect of laser modulation parameters on the peak,signal-to-noise ratio,peak width,symmetry,and signal integrity of second harmonic signals,the analysis based on the hardware system and the Simulink analogue model were verified that the theoretical simulation results were consistent with the signal variation trend of the hardware system,and at the same time the optimal modulation parameters of the CO_(2)detection system were determined.Through the experimental system,the absorption spectra of different volume fraction of CO_(2)at 1432.04nm were measured,the inversion model of the signal intensity at the main absorption peak and CO_(2)volume fraction was established,and the system performance and measurement accuracy were analyzed.The results show that the linear fitting coefficient R^(2)is 0.9998,the maximum relative error of gas volume fraction inversion is 0.7333%,and the detection limit of the system is 0.0074%.The ideal second harmonic signal can be obtained through the optimal selection of modulation parameters,so as to achieve accurate inversion of the gas volume fraction to be measured.The study provides an important reference for the optimization of modulation parameters in the detection system and provides guidance for the improvement of the measurement accuracy of the system.