AC voltage standard based on a programmable SIS array

An AC voltage standard is being developed based on phase sensitive detection of the amplitude of the fundamental frequency component of the output of a programmable Josephson voltage array. The setup is described and requirements for relative uncertainties less than 10/sup -7/ at 1 kHz and 1 V are discussed. According to preliminary experiments, the constructed current bias is able to drive the array from -1 to +1 V within less than 100 ns