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The Research Of Distributed Optical Fiber Temperature Sensor System And Weak Signal Processing

Posted on:2011-05-11Degree:MasterType:Thesis
Country:ChinaCandidate:X WeiFull Text:PDF
GTID:2218330338972855Subject:Circuits and Systems
Abstract/Summary:PDF Full Text Request
Distributed optical fiber temperature sensor with not only the small size, the structure variable, anti-electromagnetic interference and other features, that are the optical fiber being provided with itself, but also real-time measurement of the whole fiber length on the temperature changes, and hence can be distributed along the fiber optic temperature distribution. It has broad application prospects in the industrial, construction, aerospace and military fields, so the study of distributed fiber optic temperature sensor has been hot at home and abroad.Based on the analysis and comparison of different distributed optical fiber sensing mechanism, the Raman scattering is used to achieve the distributed optical fiber temperature sensing system.In this dissertation, the research and analysis of fiber Raman scattered light as well as the principle of optical time domain reflectometry (OTDR) were carried out, and according to the characteristics of temperature signals under test, the ratio of the backward Rayleigh scattering and the anti-Stokes scattering is used as the system temperature demodulation method. According to the signal characteristics and signal processing methods, the structure of the distributed fiber optic temperature sensor system is designed, and the each sub-systems are introduced.As the analytical signals are weak signal, in this dissertation, the detection theory and basic methods of weak signal were analyzed. According to the characteristics of the noise signal, based on the comparison of the two kinds of improved weak signal processing methods, the approach of sampling integral and the rate of wavelet multi-identified are proposed. With this, the system noise is effectively eliminated and system SNR and system performance are improved. In this dissertation, signal processing circuit is researched and the scanning control circuit, photoelectric detection amplifier circuit, A/D conversion, signal acquisition, as well as the scan output and other circuits are designed. In accordance with circuit design, the hardware circuit is programmed and is gave full play to make a valid match. The combination of hardware and software is achieved, and a high integration and strong practicability of circuit are designed.Figure 34 table 1 reference 55...
Keywords/Search Tags:distributed optical fiber temperature sensor, Raman scattering, signal, detection, weak signal processing
PDF Full Text Request
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