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Research Of Temperature Demodulation And De-noising Method In Fiber Optic Temperature Measurement System

Posted on:2011-10-12Degree:MasterType:Thesis
Country:ChinaCandidate:Y L LiuFull Text:PDF
GTID:2218330338472867Subject:Circuits and Systems
Abstract/Summary:PDF Full Text Request
Compared with other types of sensing systems, the distributed optical fiber temperature measurement system has a very distinct advantage. It has good corrosion resistance, against ability of the electromagnetic interference and so on. Fiber is used as sensor, and also as a transmission path. More and more researchers are researching distributed optical fiber sensing system. They find many the corresponding the ways and methods of study. The ways and methods provide a good theoretical basis for the development of distributed optical fiber sensing system. Following the research of predecessors, this article made the following research.This article introduces the classification of fiber optic sensors, the research and development of the distributed temperature sensor at home and abroad, the principle of the distributed temperature sensor. It makes a comprehensive and in-depth introduction about distributed fiber optic temperature sensing based on Raman scattering. Provide a good theoretical basis for the design of distributed optical fiber temperature sensing system design and signal processing systems. Describes some signal demodulation methods about distributed optical fiber temperature sensor. Based on of the principle of several signal demodulation methods of distributed optical fiber temperature sensor, the dual-channel demodulation methods of rayleigh scattering and the anti-stokes scattering in Raman scattering chosen. Because the signal of the temperature measurement system is very weak, it is essential to improve the SNR. The article also describes the problem of signal de-noising of distributed optical fiber temperature sensing system and several processing methods of weak signal. Wavelet decomposition and cross-correlation method is used to improve the SNR. The article also describes the design of signal acquisition and processing system's hardware and software. It makes a simple description of the circuit. The results of test are proved to be very good.Finally, the optical fiber temperature sensing system was tested. Tests show that the system's key performance indicators, such as accuracy, positioning resolution, linearity, wavelength, measuring distance, measuring points, power, measurement accuracy, can meet actual requirements. However, the response time still need to continue to improve.
Keywords/Search Tags:distributed temperature measurement, Raman scattering, wavelet de-noising, signal acquisition and processing, cross-correlation process
PDF Full Text Request
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