DC Comparison of a Programmable Josephson Voltage Standard and a Josephson Arbitrary Waveform Synthesizer

We present the first dc comparison of a programmable Josephson voltage standards and a pulse-driven Josephson arbitrary waveform synthesizer (JAWS) at 3 V. Both circuits are mounted side-by-side on the cold stage of a cryocooler. The relative agreement achieved was better than 1 part in 10
⁸
. This measurement allowed us to identify systematic errors of the JAWS system. An undesired current injection from the JAWS isolation amplifier into the measurement circuit was responsible for an error voltage of a few nanovolts.