Design Of A Dual Channel Acquisition Module For Distributed Optical Fiber Sensing System

The high-speed and high-precision acquisition module is a critical component in the distributed optical fiber sensing system.For this system,its spatial resolution and temperature resolution are constrained by the performance of the acquisition module.Therefore,its necessary to design a high-performance acquisition module for distributed optical fiber sensing system.This thesis provides a design of dual channel acquisition module mainly used in Raman distributed optical fiber sensing systems.The main research contents are as follows:1)The analysis of acquisition system based on Raman fiber sensing principle.This thesis studies the related theory of optical fiber sensing system,analyzes the temperature measurement principle and temperature demodulation method of Raman optical fiber sensing system.it further discusses key position and index requirements of the acquisition system.2)Hardware design of dual channel acquisition module.Through in-depth discussion of the specific design indicators and functions of the dual channel acquisition module,this thesis proposes a high-performance acquisition module hardware design programme with 1GSPS sampling rate,14 bits signal quantization number.3)Logic design of dual channel acquisition module.In order to achieve the corresponding functions,Vivado is used to design the logic program of the acquisition module,which implements the configuration of peripheral devices and the reception of high-speed sampling data.In addition,this thesis implements a denoising logic based on dual-port RAM,and completes the temperature demodulation of the Raman optical fiber sensor system in the dual-channel acquisition module.Finally,this thesis designs a synchronous pulse generation logic with controllable parameters to control the semiconductor optical switch in the optical fiber sensor system for generating laser pulses.Finally,the hardware platform of dual channel acquisition module designed in this thesis is tested and verified.Correlation verification shows that the dual channel acquisition module has 1GSPS,14 bits sampling and quantization capabilities,and has a200 MHz analog bandwidth.By changing the number of accumulation,the accumulated average denoising logic which is based on dual-port RAM is capable of denoising.The final signal-to-noise ratio of the acquisition module is greater than 75 d B.Throush the simulating test environment of the optical fiber sensor system,the temperature demodulation function and the synchronous pulse generation function of the acquisition module are verified.Its concluded that the dual channel acquisition module in this thesis meets the criterions and achieves the expected design purpose.