Research on differential sampling with a Josephson voltage standard

This paper describes a differential sampling method that uses a commercial sampling Analog Digital Converter (ADC) and the Programmable Josephson Voltage Standard (PJVS) to measure the ac voltages provided by the Fluke 5720A calibrator. After averaging, the type A uncertainty obtained in the determination of the amplitude of a 0.7 V rms ac voltage at 62.5 Hz is less than 1 μV.