Accuracy of a cryocooler-based programmable Josephson Voltage standard

A cryocooler-based programmable Josephson array voltage standard (JAVS) for 4-K operation and a very compact microwave source are described. Both components are crucial for future mobile voltage standards. A direct comparison between two programmable JAVS using these components was performed at 1 V in order to test whether these systems are suitable for metrological application at the highest level of precision. The results of the comparison show that the new components are suitable for mobile JAVS with an uncertainty of less than 1 × 10^-9.