AC-DC Transfer Standard Measurements Using An AC Josephson Voltage Standard

NIST is implementing the Josephson arbitrary waveform synthesizer as an ac Josephson Voltage Standard (ACJVS). Over the past few years we have demonstrated precise measurements of synthesized sine waves at rms voltage amplitudes up to 170 mV. The system can generate a variety of precision voltage outputs including dc voltages and ac sinewaves, so it can be used as a quantum-based voltage source for ac metrology. In this paper, we explore the capability of the ACJVS as an audio frequency calibration source for the lower voltage ranges of an ac-dc transfer standard such as the 220 mV range where the transfer standard uses a high-impedance input buffer amplifier. In particular, we investigate the ACJVS measurement accuracy over the frequency range from 1 kHz to 10 kHz at 50 mV and 100 mV. This work demonstrates the feasibility of a practical ac Josephson voltage standard based upon a quantum voltage source that produces precisely calculable ac and dc voltages.