Design of Online Automated Calibration System in Intelligent Testing Instrument

摘要

In this paper, a design method of the standard voltage signal source which is based on the DC-DC converter chip Max5026 and digital potentiometer ds1805e, with adjustable output for the use of online automated calibration in the intelligent testing instrument is introduced. Then according to the principle that input minus output equal to the error compensation amount, using the intelligent testing instrument’s error compensation amount and the standard data under the standard voltage signal source input to build a mathematical model. By the Parameter Estimation of errors regression model’s least-squares method, we can get the linear error compensation model mathematical equation, using the statistical methods of hypothesis testing to construct the F statistics and make a linear effectiveness test of βi. So the effective linear error compensation model can be determined. If the system error linear regression is not significant, we can do a nonlinear correction on the measurement data with piecewise linear method to find a whole range error compensation mathematical expression which is correspond to the input and output, then complete the intelligent testing instrument online automated calibration.