Interlaboratory comparison using a transport Josephson voltage standard system

A portable Josephson voltage standard (JVS) system has been used as a transfer standard to make an interlaboratory JVS comparison. The results are compared with an interlaboratory comparison between the same two JVS systems using transport Zeners made at about the same time. The portable JVS improves the uncertainty of the comparison by largely eliminating the problem associated with non-ideal Zener transportability, environmental dependence, and non-linear drift.