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This paper describes a method to extend the frequency range of Programmable Josephson Voltage Standard based ac voltage calibrations. It requires coherent (synchronous) signal generation and sampling to a common reference time-base of a digitizer and accurate phase alignment of ac signals. Practical and physical limitations of the underlying principle are covered in the text. Experimental investigations...
This paper describes the development of a primary single-phase sampling ac power standard, which uses a programmable Josephson voltage standard (PJVS) in its core. Magnetic transducers are used to scale down to low levels the ac signals to be compared with the PJVS by digital sampling. Independent digital adaptive regulators in form of algorithms in a control software guarantee stable and accurate...
This paper describes the réévaluation of Inmetro Conventional (CJVS) and Programmable (PJVS) Josephson Voltage Standards uncertainty budgets for Zener calibration. An intralaboratory indirect comparison between the two systems was made in order to check the consistency of the uncertainties. The achieved uncertainties are ±40 nV (at 1.018 V) and ±250 nV (at 10 V), k=2.
This paper describes a new calibration system developed at INMETRO to guarantee traceability of low-frequency alternating (ac) voltage calibrations (up to around 1 kHz) to a programmable Josephson ac waveform synthesizer. The automated full synchronous system allows the synchronization of a calibrator or signal synthesizer with a programmable Josephson voltage synthesizer system to be made by employing...
This paper describes a measurement setup employed to investigate differential voltage measurements to be done with a spectrally pure sine wave and a dc reference. The system enables adjustment, to a very high accuracy, the start phase of ac sampling. Repeatabilities of some 0.1 µV/V were obtained with the help of adaptive digital control.
This paper presents the setup for investigating INMETRO's programmable ac voltage standard with thermal converters. Of primary interest is the validation of differential ac voltage calibrations of the Josephson system with thermal converters and their calibration against the quantum system. Proposals for attaining these goals are presented.
This paper describes a 10 V Josephson Voltage Standard (JVS) direct comparison between the National Institute of Standards and Technology (NIST) and the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO) using automatic data acquisition. The results were in agreement to within 1.1 nV and the mean difference between the two JVSs at 10 V is 0.54 nV with a pooled combined...
In this work we present a general method, commonly applied to the numerical analysis of stochastic models, to interpolate AC-DC differences δ between calibration points in AC-DC thermal standards. This method assigns power-law behavior to AC-DC differences, solely under the assumption that δ is some smooth varying function of voltage and frequency. We argue it may be straightforwardly applied to all...
This paper describes a 10 V Josephson Voltage Standard (JVS) direct comparison between the National Institute of Standards and Technology (NIST) and the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (Inmetro) using automatic data acquisition. The results were in agreement to within 1.1 nV and the mean difference between the two JVSs at 10 V is 0.54 nV with a pooled combined...
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