In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have established the structure of the sensor and designed weak signal detecting circuit of the sensor based on infrared spectrum absorption principle,differential de-noising principle and weak signal detecting principle.The authors have made experiments using CH4 gas.The results show that the circuit can remove noise effectively and detect weak electrical signal obtained from the detector.
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School of Electronic and Information Engineering, Beihang University, Beijing 100191, China;
Engineering Technology Research Center of Shanxi Province for Opto-Electronic Information and Instrument,North University of China, Taiyuan 030051, China;