Research On Demodulation Technology Of Fiber Bragg Grating Sensing Signal Based On DSP

Fiber Bragg grating sensor is a function fiber-optic sensor which uses fiber Bragg grating as the sensitive device, distributed optical fiber Bragg grating sensor constituted with it has a broad application field. When the sensor undergone the external parameters, such as the temperature the strain, the Bragg wavelength will drift correspondingly. Therefore, the main problem about researching on fiber Bragg grating sensor is how to measure the wavelength shift reflected by the fiber Bragg grating.This thesis analyzes the deficiencies of the traditional circuit transformation, the peak detection and the correlation peak detection method. Based on F-P tunable filter, a processing technology combining subsection FFT convolution computation method with linear interpolation method is presented. This thesis analyzes two aspects both the theory and MATLAB simulation, verifying the theoretical feasibility of this method.According to the actual situation and specific algorithm requirement, selecting DSP chip (TMS320VC5416) and the peripheral circuits, design and make the hardware circuit board. Using C language and assemble language to complete the core algorithm and the software design that based on hardware design, and preparation of a PC interface with VB.Using the simulation signal source, the presented algorithm is achieved on the hardware circuit board. From the data obtained from the host computer interface can see that the wavelength shift can be calculated directly. Compared with the peak detection and subsection FFT convolution computation method, this method has smaller error; compared with the correlation detection method, computational load is lower using this method, and can process the data faster.