Applications of Programmable Josephson Voltage Standard for AC Voltage Metrology

Abstract

Over the last half-century, the most fundamental measurement of AC voltage has been done by comparing the Joule heating of an unknown AC signal to that of a reference direct DC voltage using thermal voltage converters (TVCs). However, the accuracy of AC-DC difference measurements of the TVC is limited by the accuracy of the model describing the AC-DC difference of the reference TVC. To satisfy the requirements for improved AC voltage metrology, national metrology institutes are developing quantum standards based upon the Josephson effect. These quantum-based AC voltage standards have significant advantages over a conventional measurement method in terms of accuracy and versatility. This article reviews the fundamental principle of AC voltage measurements with a conventional method based on a TVC and application of the AC-programmable Josephson voltage standard system using a sampling technique for the measurement of the AC-DC difference at low frequency.