Real time self-calibration of digital measurement system

The measurement system can be seen as a system converting input measurand into output measurement result using plenty of technologies like conversion, comparison, processing, etc. However, the unideality of various internal conversion and processing units as well as the influence by external environmental factors leads to measurement errors. In this paper, the most typical mathematical model and measurement error expression influenced by conversion error (gain error) and zero drift in common measurement systems and digital measurement systems are illustrated. For digital measurement system, a real time self-calibration technology which can be used in the measurement of electrical and non-electrical measurand to obtain high precision is suggested in order to diminish or even eliminate conversion error and zero drift. Test data by a self-designed data acquisition system based on the real time calibration implementation is provided at the end of the article. Through real time calibration, high precision measurement design of a digital voltmeter or high-precision data acquisition can be achieved. Therefore, the application of real time self calibration in engineering is worthwhile.