光谱吸收式的气体传感器时分复用系统

Time-division multiplexing gas sensors based on spectroscopy absorption

在基于可调谐二极管激光器吸收光谱学(TDLAS)技术的多点气体监测系统中,所需的激光器造价昂贵,使用多路气室共用一套光源与光探测器的复用技术可以降低单个测量点的造价.在此利用了一种灵活的新型拓扑结构,解决了传统拓扑结构中由于布局光纤造成的光信号延时而给信号采样带来的麻烦.并且给出了一套数字化的基于TDLAS技术的时分复用检测方案,并将数字正交锁相放大技术应用在时分复用检测系统中的谐波提取,消除了各路检测信号中相位对气体浓度检测的影响,得到更加高效的信号处理方案.基于Matlab的4路时分复用气体检测仿真系统验证了理论方案的可行性.

The multi-point gas monitoring technique with tunable diode laser absorption spectroscopy（TDLAS） requires expensive lasers.The multiplexing technology sharing one set of laser and light detector can reduce the cost of a single measurement point.This paper uses a flexible gas monitoring topology.It resolves the trouble that the fiber used for layout between sensor cells make the signal delay in traditional topology and thus makes the signal sampling easy.This paper also gives a digital time-division multiplexing solution based on TDLAS and brings the digital orthogonal phase-locked amplifier technology into the harmonic extraction.It makes the gas concentration measurement escape being affected by the different phase difference in every monitoring load,obtaining a more efficient signal processing program.Finally a 4-channel TDM（time division multiplex） gas monitoring system is built to verify the feasibility of the program.