Study on the Detecting Scheme of Absorptive Spectrum Optical Fiber Methane Gas Sensor
|School||Harbin Engineering University|
|Keywords||Methane Spectral absorption Fiber Gas Sensor Detection scheme Wavelength modulation|
The methane is the the major harmful gases in the mine , but also produce one of the main greenhouse effect gas research in real-time , rapid detection of methane gas concentration sensor has important theoretical and practical significance . Spectrum absorptive optical fiber gas sensor and gas sensor is compared with the advantages of high sensitivity, the ability of gas to identify , fast response , simple and reliable , and has broad application prospects in the field of industrial production , and environmental monitoring . The target methane gas , to study the spectral absorption optical fiber gas sensor detection scheme . The thesis describes the basic principle of the spectral absorption -type fiber-optic gas sensor , and the characteristic spectral lines of methane analyzed selected absorption lines located 1653.72m absorption line as a detector , and to determine the line parameters . Secondly , a more complete introduction to the basic principles of the spectral absorption optical fiber gas sensor detection technology , their advantages and disadvantages , applications and technical difficulties , and their performance summarized and compared . The paper focuses on the wavelength modulation technique , its principle and technical difficulties ; using the model based on the Fourier Transform analysis of the wavelength modulation signal strength - frequency modulation signal on the basis of frequency modulation signal model is given a theoretical describe, analyze the intensity modulation of the signal characteristics ; based on theoretical analysis , the overall structure of the program based on the detection of wavelength modulation technique , and specifically discussed the key issues for program implementation and research to determine the normalized a scan range of frequency modulation amplitude and triangular wave method of removing the triangle wave and get the first harmonic of the central value ; simulation using MATLAB software to verify the theoretical analysis and the feasibility of the program .