Research And Design Of Multi-channel High Dynamic Range Data Acquisition System

In recent years,with the development of sensor technology and information processing technology,the application fields of data acquisition systems have become more and more extensive.The improvement of sensor performance and the development of geophysical technology make the requirements of data acquisition systems higher and higher in terms of dynamic range,number of channels and portability.In this paper,the research and design of multi-channel high dynamic range data acquisition system is carried out for the signal acquisition requirements of electromagnetic induction sensors,geophones and ICP acceleration sensors used in geophysical exploration.This paper explores the research and design of multi-channel high dynamic range data acquisition systems,which solves the signal acquisition requirements of electromagnetic induction sensors,geophones,and ICP accelerometers used in geophysical exploration.According to the actual signal characteristics and the environmental conditions in the field,the overall design of the data acquisition card with adaptive signal matching amplifier is designed.In this paper,the design scheme of each part of the system is introduced in detail,and the adaptive amplification acquisition technology scheme and the long-line transmission signal scheme of the coaxial cable involved in the actual application of the system are preliminarily verified.Then,the circuit of the front channel of the data acquisition card is designed by analyzing the noise distribution model on the signal channel.In order to improve the accuracy of the collected data,the 24-bit acquisition circuit is designed.In order to realize the portability of the design product,the USB communication interface circuit is designed.A three-channel low-noise adaptive signal matching amplifier is designed by studying the low-noise design method of the amplifying circuit and the filtering circuit.Power system design on data acquisition card and adaptive signal matching amplifier is completed by using DC-DC power supply and LDO power supply.Then,by using the Verilog HDL hardware description language to write the FPGA logic control program,the data acquisition card realizes the hardware function of setting the working mode,collecting signals and transmitting data,and the adaptive signal matching amplifier realizes the hardware function of adaptive amplification.Finally,the data acquisition card driver is integrated by using VC++,and user interface is designed by using Lab VIEW,and the algorithm of weak signal reconstruction has been verified by research,and the reconstruction of the weak signal collected by the system is implemented by using MATLAB.Through the step-by-step test and the overall test analysis of the system,the functions and performances of the data acquisition card and the adaptive signal matching amplifier meet the original set requirements,and the function of the user interface and the function of the program for reconstructing weak signals are basically realized.The overall system can measure signals from ±50n V to ±0.5V over long distances,and can measure signals from ±0.8u V to ±10V at close range.The dynamic range of the measured signals at the far or near distance of the system reaches 140 d B,which solves the problem of wide dynamic range of sensor signals and complex signal acquisition environment in geophysical exploration.