Evaluation of linearity in digital voltmeters using PJVS

We are evaluating the linearity characteristics of digital voltmeters (DVMs) using a programmable Josephson voltage standard (PJVS) system. The PJVS system is composed of a 524 288 junction array and a 10 K compact cooler, which enables to generate an arbitrary output voltage of more than 10 V. The voltage signal output with the PJVS system was applied to DVMs, and the linearity characteristics were investigated based on the reading values of the DVMs. As a result, we found that the linearity characteristics can be evaluated with the expanded uncertainty of 0.1 μV/V or better for the 10 V or smaller ranges.