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An AC Josephson voltage standard system for frequencies up to the kHz range tested in an industrial environment
Abstract
This paper describes the performance of a new turn-key AC quantum voltmeter, an AC Josephson voltage standard system, used for calibration of common DC and AC voltage standards. The capabilities and handling of the system in an industrial environment were investigated and are discussed here. Several Fluke 5700A series calibrators were tested and their voltage and frequency dependence is characterized in the range of DC to 1 kHz with amplitudes up to 10 V. The combined measurement uncertainty for AC measurements was determined to be less than 1 μV/V.
... The measurements were continuously repeated for a total time of about 1 h. The 10 V dc output was measured for 2 h and the first 3 min are omitted to eliminate a possible calibrator turn-ON effect [13]. The dc stability for 10 V [ Fig. 3(e)] is remarkable with only 50 nV (5 × 10 −9 ) after 1 min. ...
... The identified optimal configuration is shown in Fig. 8. For example, higher leakage is observed when the sampler is connected between the LO-sides [13] or the HI-sides of the instruments. Also a possible influence of the multiplexer isolation impedance is included. ...
This paper describes the development of an automated ac quantum voltmeter toward a turnkey system, which can be used for calibration of common dc and ac voltage standards. The setup was tested in an accredited commercial calibration laboratory to characterize Fluke 5700A calibrators and voltage standards. The measured voltage in dependence on various parameters is presented in the range of dc to 2 kHz with amplitudes up to 10 V. The uncertainty components are discussed, and the system relevant Type B uncertainty for ac voltage calibrations is 0.15 /V. The contribution of the leakage current is investigated in detail and found to be notable for frequencies above 1 kHz due to parasitic capacitances. The combined measurement uncertainty for calibration ac voltages is less than 0.62 /V ( k=1 and 40 Hz–1 kHz) and is limited by the noise of the calibrator. Comparison measurements at Physikalisch-Technische Bundesanstalt have been done and confirm the system reproducibility.
... (7 V RMS, 375 kHz) [7] 6 µV 3 µV Max. deviation (6 V RMS, 1 kHz) [8] ±69 µV Max. deviation (7 V RMS, 1 kHz) [7] ±24 µV ...
This document presents some considerations on the future inter-comparison of AC Programmable Josephson Voltage Standards (ACJVS) between two National Metrology Institutes. Namely Türkiye Bilimsel ve Teknolojik Araştirma Kurumu (TUBITAK) and Czech Metrology Institute (CMI) are considered as candidates.
An ac quantum voltmeter based on a 10 V programmable Josephson array that is simple to use, provides dc and ac calibration up to kHz range for equipment widely used in metrology, and ensures direct traceability to a quantum-based standard, is developed. This ac quantum voltmeter is proven to match conventional Josephson standard systems at dc and extends its advantages up to 10 kHz in the low-frequency ac range. The ac quantum voltmeter is capable of performing calibrations up to 7 VRMS in the frequency range from dc to 10 kHz completely under software control. A direct comparison at dc has demonstrated an uncertainty better than 2 parts in 1010 (k = 2). The uncertainty at 1 kHz is better than 1.7 µV V−1 (k = 2) for a measurement time of 1 min. The ac quantum voltmeter is a robust and practical system that fulfils the needs of general metrology laboratories for quantum-based voltage calibrations.
A 10 V programmable Josephson voltage standard has enabled sine waves with voltages up to 7 V RMS to be accurately measured with a differential sampling measurement technique. Expanding the voltage range for this technique enables the direct calibration of the low-frequency ranges of commercial calibrators in the ac voltage mode. This paper reviews the practically achievable performance and challenges of the differential sampling measurement technique that arise when measuring RMS voltages greater than a few volts. A relative Type A uncertainty of 4 parts in 107 was achieved with the technique when measuring a 7 V RMS sine wave generated by a calibrator at 62.5 Hz.
This paper describes a Josephson-voltage-standard-locked synthesizer where a commercial digital-to-analog converter is used as a sine wave generator. The output amplitude of the generator is controlled by the calculable fundamental of the stepwise waveform generated by a SINIS Josephson junction array. Such a system combines the versatility of a commercial source with the stability and accuracy of the Josephson standard. By discarding the measurements performed during the transients, broad voltage steps of 1.7 mA were obtained up to frequencies of 500 Hz.
A new method for calibrating ac voltage waveforms based on measuring the difference relative to a synchronously synthesized waveform supplied from a programmable Josephson array is presented. In order to test the accuracy of this approach, the differences between two Josephson waveforms have been measured at the 1.2-V level for frequencies up to 5 kHz. The uncertainties achieved are at least a factor of ten lower than those from the direct sampling method. Below 400 Hz, this new method gives an uncertainty of 5 10-8 (k = 1), while at 1 kHz, the uncertainty is about 2 107 (k = 1)