基于高频参考光的频分复用技术实现强干扰下的气体浓度测量

Measurement of Gas Concentration Under Strong Interference by Frequency Multiplexing Based on High-Frequency Reference Signal

在利用激光吸收光谱技术测量气体参数时,复杂环境中存在的强干扰会对提取到的探测光强的谐波信号产生较大影响,导致气体参数检测不准确。为此,提出了一种基于高频参考光的频分复用技术。该技术利用高频参考信号实现了对干扰信号的提取与探测光强的修正,进而准确地提取到了探测光强的谐波信号,提高了气体参数测量的准确性,拓展了光谱吸收法的应用范围。通过数值仿真及搭建甲烷浓度实验系统,验证了所提方法具有高频干扰抑制效果好、气体参数测量准确性高的特点。

In the harsh measurement environment, the high-frequency interference has a great impact on the harmonic signal and reduces the measurement accuracy of gas parameters when using absorption spectroscopy method. To improve the target detection performance, frequency multiplexing based on high-frequency reference signals is proposed. The method can extract interference signals and correct the transmitted intensity of reference signal by using a high-frequency reference signal, thereby accurately extracting the harmonic sighanl of detected signal, improving the accuracy of gas parameter measurement and expanding the application range of absorption spectroscopy method. The numerical simulation and the establishment of experimental measurement system to measure the molar fraction of methane verify that the method has the advantages of excellent high-frequency interference suppression and high measurement accuracy of gas parameters.