TDLAS技术气体检测二次谐波信号的仿真与分析

可调谐半导体激光吸收光谱(TDLAS)技术结合半导体激光器可调谐的特点及气体分子对特定波长能量光的吸收特性,凭借灵敏度高、响应时间短等优势广泛应用于气体浓度检测。TDLAS技术气体浓度检测包括波长调制、气体吸收、二次谐波解调等环节,吸收信号的二次谐波分量携带气体浓度信息,用于计算气体浓度。利用MATLAB对气体检测过程进行了信号仿真,并利用数字锁相放大算法提取了二次谐波信号,验证了二次谐波与气体浓度的关系。通过仿真分析了二次谐波信号随调制系数的变化关系,以便确定较佳的调制参数,为后续系统搭建与气体检测实验提供参考。

Simulation and analysis of second harmonic signal gas detection based on TDLAS technology

The tunable semiconductor laser absorption spectroscopy(TDLAS)technology combines tunable characteristics of semiconductor lasers with absorption characteristics of gas molecules for specific wavelength energy.It is widely used in gas concentration detection due to its high sensitivity and short response time.The gas concentration detection includes wavelength modulation,gas absorption,second harmonic demodulation.And the second harmonic component of the absorption signal carries gas concentration information for calculating the gas concentration.The signal simulation process is simulated by MATLAB software,and the second harmonic signal is extracted by digital lockin amplification algorithm.The relationship between the second harmonic signal and the modulation coefficient is analyzed by simulation to determine the better modulation parameters,which provides a reference for the subsequent system construction and gas detection experiments.