基于气体特征光谱吸收和谐波检测的瓦斯浓度测量技术

Measurement technology of methane concentration based on harmonic detection and characteristic absorption of gases

基于瓦斯的光谱吸收特性，采用分布反馈式半导体（DFB）激光器和性能良好的气体吸收室，利用数字锁相放大器SR830，对不同瓦斯浓度的一次及二次谐波信号进行了测量，并用LabVIEW软件分析数据．通过对实验数据的分析验证了瓦斯浓度在0—5％范围内与一、二次谐波比值有较好的线性关系，证实了二次谐波检测理论的优越性．

Based on the spectrum absorption properties of methane, adopted the Distributed Feedback LD, high performance gas absorption cell, the lock-in amplifier SR830 was used to measure the first and second harmonic signals for different methane concentration, and analyzed the data with LabVIEW. The analysis data validated the good linearity between the methane concentration and I2f/If （second harmonic/first harmonic）, confirmed the superiority of second harmonic theory.