Comparison of the 10 V josephson voltage standards of the conventional and the programmable at NIM

A direct comparison was carried out between the Josephson voltage standard (JVS) of the National Institute of Metrology (NIM), China, and the programmable Josephson voltage standard (PJVS) available from the National Institute of Standard and Technology (NIST) at the 10 V level. The BIPM.EM-K10.b comparison protocol was applied for this comparison. It required the PJVS to provide a reference voltage for the measurement by NIM using the JVS. The paper presents the exercise performed and the comparison results. The final results were in good agreement with the relative deference of 1.8 parts in 10¹⁰ within the combined relative standard uncertainty of 4.0 parts in 10¹⁰ for the nominal voltage of 10 V.