Sampling Measurement of a 20-V RMS Sine Wave Using an Inductive Voltage Divider and an AC-Programmable Josephson Voltage Standard

We have performed a differential sampling measurement of a sine wave with voltages up to the root-mean squared (RMS) amplitude of 20 V by combining an inductive voltage divider and an 10 V AC-programmable Josephson voltage standard. Expanding the voltage range of this technique enables the calibration of a calibrator and a digital voltmeter above the RMS amplitude of 10 V. The operating principle and a preliminary result are presented. The Type-A uncertainty of 0.2 μV/V is achieved with the technique when measuring a sine wave from the calibrator with RMS amplitude of 20 V at the frequency of 62.5 Hz.