For a number of years, NIST has been developing a Josephson arbitrary waveform synthesizer as an ac Josephson Voltage Standard (ACJVS). The effort has primarily focused on increasing the output voltage to practical levels. Recent advances in circuit design and superconducting integrated circuit fabrication have enabled us for the first time to demonstrate waveforms with a 242 mV peak voltage. This larger output voltage now allows us to perform practical metrology measurements with rms amplitudes up to 170 mV. The new system can generate a variety of precision voltage waveforms, including dc voltages as well as ac sinewaves so that the system can be used as a quantum-based voltage source for ac metrology. In this paper, we present experimental results using the ACJVS to measure an ac/dc transfer standard at audio frequencies on its lower voltage ranges, namely the 22 mV to 220 mV ranges where the transfer standard uses a high-impedance buffer amplifier on its input. This work demonstrates the feasibility of a practical ac Josephson voltage standard based upon a quantum voltage source that delivers precisely calculable ac and dc rms voltages.
Proceedings Title: Nat'l Conf. of Standards Laboratories (NCSL)
Conference Dates: August 17-21, 2003
Conference Location: Tampa, FL
Pub Type: Conferences
ac Josephson standard, Josephson arrays