Voltage linearity measurements using a binary Josephson system

A fully automated system has been developed for voltage calibrations where fast programmability and extremely low uncertainties are required. This system is based on a binary Josephson junction array with a smallest segment of one single junction. As an important application, the linearity of the 10 mV range of a digital nanovoltmeter was determined with a standard uncertainty better than 1 nV. As a further application of the fast programmability of the binary Josephson system, the standard uncertainty of voltage ratios measured by an -digit digital voltmeter in quantum Hall measurements was measured to be 10 X 10-9.