Design Of High Speed Fiber Bragg Grating Sensing Demodulation System Based On FPGA

In recent years,the sensing demodulation technology of fiber Bragg grating has been developing rapidly and its application field becomes increasingly wide,which emerge the demodulation products at home and abroad.Therefore,more requirements are defined when choosing a demodulation product.Since the accuracy,speed,structure and price of the existing demodulation products can not all be accounted,the application of fiber grating is hindered to some certain extent.Based on the research of fiber grating sensing and demodulation technology,this paper,using FPGA as the core of signal processing,and improving the demodulation precision and processing speed by adopting high-speed AD chip and FPGA chip and applying improved demodulation algorithm,designs a complete set of high-speed fiber grating sensing demodulation system.The system design is divided into two parts,the host computer and the lower computer,and the respective hardware and software design.First,the FBG sensor package is designed so that the fiber grating sensor can monitor the variation such as deformation in the engineering environment.The demodulator system of the lower computer adopts real-time acquisition of high-speed AD,and uses FPGA as the master chip to process the signal.MicroBlaze technology is used to build the soft-core processor and the MicroBlaze IP core is developed in the EDK,also designs the hardware circuit of each function module,the control program is compiled to achieve the fiber demodulation drive,acquisition and processing and network communication functions.The demodulation system uses the LM peak localization algorithm to obtain the center wavelength of the FBG and transmits the relevant data to the host computer through the W5300 network module.The host computer uses the LabVIEW platform to realize the communication,system login,monitoring information display and data storage query function of high speed optical fiber demodulation system.Finally,the test shows that the FBG sensor after the operation is stable,and the LM peak localization algorithm is stable and effective,the demodulation speed of the system can reach 2kHz and the demodulation accuracy can reach 0.003 nm,which meet the requirements of high speed and high precision,and the monitoring system is easy to operate.The system debugging has achieved the desired results.