Demodulation Algorithm And Data Processing And Performance Of FP Sensing System

As an important branch of optical fiber sensor,Fabry-Perot(FP)sensor has been widely used in space,medical,architecture and other fields.For demodulation of optical fiber FP sensor,the traditional demodulation method based on cavity length analysis needs a wider spectrum to get a higher demodulation resolution.It is not suitable for the application of the demodulation system,and it is not suitable for the application of the demodulation system.In order to reduce the cost of demodulation,this thesis proposes an efficient demodulation algorithm which can achieve high resolution and large dynamic range measurement in a narrow spectral range.Based on this demodulation algorithm,this thesis develops an integrated software demodulation system and applies it to practical engineering,and achieves good application results.The main contents of this thesis are as follows:1.Theoretical analysis of Chirp-Z Transform(CZT)phase demodulation algorithm shows low demodulation speed and linearity of measurement problems.In order to better meet the demand of high efficiency and high index demodulation,this thesis proposes a fitting calculation local peak demodulation algorithm based on peak value according to the relationship between the changes and sensor cavity length change,the spectral peak as the sensor parameter tracking.The demodulation algorithm and the CZT phase demodulation algorithm are compared and analyzed.The results show that the demodulation speed is 44.7%,the demodulation output sensitivity is 4.37 times higher than that of the demodulation,and the measurement linearity is over 0.9999.2.According to the noise of the spectral data and demodulation results,a variety of denoising algorithms are adopted in this thesis.After the optimization of the denoising algorithm,the short-time fluctuation of the demodulation result is reduced by 83%.3.In view of the visual and integrated system performance required in the application project,a software demodulation system applied to optical fiber FP sensor is developed based on the local fitting peak demodulation algorithm.The system uses a modular design scheme to improve the speed control rate while ensuring the stability and functional diversity of the system,and the system is real.The time demodulation rate is increased from 600 Hz to 960 Hz.4.The performance test of the demodulation system designed and implemented in this thesis has been done,and the performance indexes of the demodulation system have been evaluated comprehensively.This demodulation system is applied to the actual balance measurement project and the pressure measurement project.The experiment proves that the demodulation system has good stability and easy operation,and meets the requirements of the project.