Design Of High Precision Miniaturized Data Acquisition Module

In the context of today's information period,there is more and more demand for high-precision data acquisition in both medical devices and industrial control or in aviation,aerospace and navigation.Today's instruments are moving in a portable direction,and the miniaturized designs are more popular.Therefore,the research on miniaturization and high precision sampling is also a direction that requires data acquisition research.This topic is based on the actual application background.According to the miniaturized high-precision acquisition module,16 channels of differential channel require the overall size of 7*7*5(cm~3),sampling rate>2kHz,DC signal accuracy of three hundred thousandths,dynamic range>90dB.The module mainly Includes 24-bit A/D,preamplifier,and filter processing for?V-level sampling accuracy.In order to realize the various requirements of the project,it is first necessary to determine the main control scheme,determine the control circuit according to the control scheme,then test and verify the functions of each module,and connect the modules into a complete system to achieve the final accuracy,sampling rate,etc.index.The main contents of this topic are as follows:1.The conditioning circuit design and A/D converter circuit design of 16 differential analog channels.According to the requirement of volume,the integrated multi-channel Sigma-Delta(?-?)type chip realizes the accuracy requirement of three hundred thousandth of the analog differential channel and meets the requirement of gain of1~128(2~n).2.Determining the control scheme,adopting STM32+FPGA control mode.STM32is mainly used for data acquisition and processing.FPGA controls ADC to collect data,and MCU is used as control expansion interface to assist STM32 and FPGA to complete their respective control functions to ensure the stability of the whole system.3.The software design of the lower computer is mainly about the design of the driving modules and the communication between the devices,as well as the software control of the digital sensor,data filtering and the calibration of channel errors.4.In order to verify the design results,the signal's conditioning module,ADC conversion module,power supply module,communication module and control module designed by the hardware in this paper work normally according to the debugging and testing results of the functional modules.The accuracy of the module meets three thousandths of one million;the sampling rate meets more than 2kHz,the floor noise,common mode rejection ratio,dynamic range,inter-channel's crosstalk,communication and other items.The index meets its performance requirements.There the whole design meets the requirements of the subject.