Direct comparison of a 1 V Josephson arbitrary waveform synthesizer and an ac quantum voltmeter

Abstract

AC Josephson voltage standards based on pulse-driven Josephson arrays (Josephson arbitrary waveform synthesizer-JAWS) have recently achieved an output voltage of at least 1 V root-mean-square. An ac quantum voltmeter (ac-QVM) based on a 2 V programmable Josephson array has been used to verify the quantization level of the new JAWS by performing a direct comparison in the frequency range from 30 Hz to 2 kHz. The comparison has demonstrated an excellent agreement between the two quantum standards of better than 1 part in 10 8 . Sources for systematic errors have been investigated. The overall uncertainty is found to be better than 1.2 parts in 10 8 (k = 1) for measurements at a frequency of 250 Hz and 1 V amplitude.

The ampere and the electrical units in the quantum era

“…Fig.14c shows the cryoprobe with the 4 chips. A direct comparison with a PJVS has demonstrated an agreement better than 1 part in 10 8 (k = 1) at 250 Hz [164]. Flower-Jacobs et al [154] have demonstrated rms amplitudes of 2 V ( fig.15a and fig.15b) [154] and recently even 3 V [170] JAWS systems are mainly used for the calibration of thermal transfer standards with high input impedance in order to avoid loading the array output.…”

“…In addition, pulse generation methods have been optimized over more than 15 years [167,168,169]. Recently, the two groups of NIST and PTB have demonstrated rms amplitude up to 3 V. Kieler et al could reach an rms voltage of 1 V by summing the voltages of 8 arrays (on 4 separate chips) for a total of 63 000 JJs [155,164]. Each array is connected to a separate channel of an 8-channel ternary pulse pattern generator in order to minimize the pulse distortion.…”

From μ 0 to e: A Survey of Major Impacts for Electrical Measurements in Recent SI Revision

“…The major difference between two techniques is the RMS amplitude and bandwidth realizations, which in the present art of traceable precision measurements are: PJVS (<7 V, <1 kHz) and JAWS (<2 V, <100 kHz). The uncertainty of AC voltage comparisons between PJVS and JAWS systems or two JAWS systems is below 1 × 10 −7 in the kHz range [44]- [46]. In the new SI system, the ohm can be directly realized by quantum Hall resistance (QHR).…”

Josephson Arbitrary Waveform Synthesizer as a Reference Standard for the Measurement of the Phase of Harmonics in Distorted Waveforms

“…The Josephson arbitrary waveform synthesizer (JAWS) [2] has been successfully implemented in a number of applications for ac metrology, such as the calibration of ac voltmeters, evaluation of thermal-to-voltage converters used in ac–dc transfer voltage standards [3]–[6], impedance bridges [7], and Johnson noise thermometry [8]. Comparisons of JAWS with programmable Josephson voltage standards and with other JAWS have shown agreement within some parts in 10 8 [9]–[11], depending on the frequency and signal magnitude. Budovsky [12] proposed the use of the JAWS for the calibration of the phase of harmonics of distorted waveforms relative to the fundamental.…”