基于自适应锁相的多气体检测系统  

Multi-gas Detection System on Adaptive Phase Lock

作　　者：李利花 袁钦 王乐平[1] LI Li-hua;YUAN Qin;WANG Le-ping(Gongqing College,Nanchang University,Gongqingcheng City 332020,China)

机构地区：[1]南昌大学共青学院

出　　处：《仪表技术与传感器》2019年第7期117-120,共4页Instrument Technique and Sensor

摘　　要：光纤广泛应用于网络信号传输,但光纤中水蒸气、氧气等气体对不同频段信号起到吸收作用。以锁相放大电路为基础进行自适应锁相介绍,根据气体浓度设计0.001°的ADA2200相敏检测器、二阶低通滤波器、变量程等检测电路,利用14位A/D采集电路、量程自调整程序等自适应模块实时调整参考信号,并根据实际氧气和蒸汽浓度进行检测系统的测试。实验结果表明浓度改变0.2 ppm时信号就会变化1 mV,且3%浓度下误差波动不超过0.027%。结果表明光纤气体检测系统可以对超低浓度气体进行检测并投入生产。Optical fibers are widely used in network signal transmission,but water vapor,oxygen and other gases in the optical fiber absorb the signals of different frequency bands.An adaptive phase lock was introduced on the basis of phase locked amplifying circuit.The ADA2200 phase sensitive detector,two low pass filter,variable range and other detection circuits were designed according to the gas concentration,and the reference signal was adjusted in real time by the adaptive module such as 14 bit A/D acquisition circuit and range self adjusting program,and the actual oxygen and steam concentration are adjusted according to the actual oxygen and steam concentration.The experimental results show that when the concentration changes 0.2 ppm,the signal will change 1 mV,and the error fluctuation will not exceed 0.027% at 3% concentration.The results show that the optical fiber gas detection system can detect ultra low concentration gases and put them into production.

关 键 词：锁相放大器 ADA2200 气体检测 光纤传输 

分 类 号：TN712[电子电信—电路与系统]