The Research On Optimization And Accuracy Improvement Of Multimeter Measurement Circuit

In the field of measuring and testing,the demand of electrical parameters is getting higher and higher.Ordinary measuring instruments cannot meet the demand of high precision measurement.It is urgent for us to develop measuring instruments with higher precision and higher stability.This paper mainly studies the measurement circuit of six and a half digital multimeter,and by analysising the structure of the traditional measuring circuit and the parameters of the various components which make up the circuit structure,and then focuses on the noise and errors that caused by the signal conditioning part of the analog signal measurement circuit,and based on the measurement circuit structural of ordinary electric voltage,electric resistance,and electric current,I will put forward a better circuit structure to reduce the entire measurement circuit system noise and error effects,in order to realize the entire measurement circuit system optimization.The main contents of the subject:1.Noise source and errors analysis of the measurement circuit.First of all,I analysis the analog signal measurement circuit of each electrical parameter measurement principle.That is,the measurement of each electrical parameter will be finally converted into DC voltage measurement.Secondly,by analyzing the structure of the measuring circuit and analyzing the errors and noise sources that affect the accuracy of the measurement circuit,including electric voltage noise,electric current noise,misalignment voltage,temperature drift and so on,and then I study the sources of these noise and errors.2.Research on noise reduction and error techniques.First of all,pointing at each level structure of the composition of the traditional measurement circuit,I propose a variety of technical methods to reduce noise and errors from different aspects,including optimizing the circuit structure,improving the power module design,and selecting the chips with a higher precision and higher stability of.Secondly,I will ultimately make the measurement circuit at each level in order to have a better conditioning effect by applying the new technical methods and design ideas to optimize the structure of the traditional measurement circuit.3.Comprehensive analysis of circuit structure.The structure of the measurement circuit will be analyzed and integrated,then,the whole measurement circuit structure is obtained.Finally,I will study the accuracy of the integrated measurement circuit.This subject uses the multimeter hardware measurement circuit optimization,and ultimately improve the measurement accuracy.After the test,the relative errors of the output value through the amplification circuit is reduced from 0.0061% to 0.00283%,and the final test errors through the analog-to-digital conversion is reduced from 0.0025% to 0.0018%,which will realize the optimization of the measuring circuit.