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This paper presents an automatic system developed at METAS for the calibration of inductive voltage dividers (IVD). The used method is primary for the n/10 ratio. With the described improvements, the calibration of IVDs has been made easier, faster and more reproducible than with the manual system used before. The uncertainties which can be reached with this new system are 28·10-9 for the in phase and quadrature parts at a frequency of 1 kHz.

An RLC bridge based on an automated synchronous sampling system has been developed using commercially available high-resolution analog-to-digital and digital-to-analog converters. This bridge allows the comparison of any kind of impedance standards in the four-terminal-pair configuration at frequencies between 50 Hz and 20 kHz within a range from 1 \Omega to 100 \k\Omega. An automatic balance of the bridge is carried out using a downhill simplex algorithm. Consistency checks have been realized by comparing resistance, inductance, and capacitance standards at different frequencies. The consistency of the measured voltage ratio is better than 20 \mu\V/V over the whole frequency range and even smaller than 5 \mu\V/V around 1 kHz. Finally, the results of the calibration of a 10-nF capacitance standard have been compared to those obtained using a commercial high-accuracy capacitance bridge. The difference is smaller than the commercial bridge specifications over the whole frequency range. [ABSTRACT FROM AUTHOR]

This paper describes a Josephson-voltage-standard-locked synthesizer where a calibrator is used as a sine-wave generator, output whose is controlled by the calculable fundamental of the stepwise sinusoidal wave generated by a programmable Josephson junction array. Such a system combines the versatility of a calibrator with the stability and the accuracy of the Josephson voltage standard. The validity of this method was confirmed with the ac–dc difference measurements of a calibrated thermal-transfer standard. The synthesizer uncertainty inferred is below 1.2 \mu\V/V for waveform frequencies up to 1 kHz and root-mean-square amplitudes ranging from 100 mV to 1 V. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Recently, ac measurements of the quantized Hall resistance have shown a linear relationship between the deviation of the Hall resistance from the perfectly quantized value ARH and the dissipation in the system represented by the longitudinal resistivity ρxxac. In this paper, we present a phenomenological model based on electrodynamic arguments that model this relation. The dissipation is due to the displacement current flowing in the system. All the microscopic features are included in a complex tensorial dielectric susceptibility which remains to be investigated if more physical insight in the ac transport properties of the 2-D electron gas is desired. [ABSTRACT FROM AUTHOR]

A systematic investigation of the current and frequency dependence of the quantum Hall resistance (QHR) and of the longitudinal resistivity has been carried out at low temperature at the center of the plateau i = 2. The deviation of the QHR from the von Klitzing constant is found to be proportional to the longitudinal resistivity and extrapolates to zero, within the measurement uncertainty, when the dissipation in the two-dimensional electron gas vanishes. [ABSTRACT FROM AUTHOR]

The frequency dependence of ac resistors as well as the ac quantum Hall resistance shows sometimes unexpected linear terms of the order of 1.107 kHz1. Three reasons for measuring linear terms are identified as systematic effects of the coaxial bridge and the compared resistors. [ABSTRACT FROM AUTHOR]

In this paper, the operation of a seven-junction electron pump is presented. To characterize the pump, a single-electron tunneling transistor capacitively coupled to the pump was used. With this device, single electrons were manipulated one at a time. By performing electron pumping at a frequency of 1 MHz, an error rate of (4 ± 1) × 10-5 was determined. This preliminary result. is a solid milestone on the way to the capacitance standard presently under development at the Swiss Federal Office of Metrology and Accreditation. [ABSTRACT FROM AUTHOR]