Design of small signal high precision acquisition system based on FPGA
Aiming at the high-precision acquisition requirements of the temperature and light intensity of the bullseye in the laser targeting experiment,field programmable gate array(FPGA)is taken as the core and a multi-channel high-precision acquisition system is implemented.The system collects the analog K-type thermocouple signal output by the signal source,takes the collected signal as a sample,estimates the gain error and offset of each channel,and uses the least squares method to obtain the required coefficient for error correction for each channel.Finally,the error is corrected by configuring AD7768.The experimental results show that the gain error before correction is 0.2078%,and the gain error after correction is 0.0027%.After the correction method is adopted,the acquisition error is achieved within 10 μV,which effectively improves the acquisition precision of the system for small signals.
field programmable gate array(FPGA)high precision acquisitionAD7768data correction
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