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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]

A test bench has been developed for systematic characterization of high-resolution analog-to-digital converters. The reference signal is generated by a programable Josephson voltage standard. Three 24-bit digitizers have been characterized. Noise performance has been measured at direct current using the Allan deviation, whereas integral nonlinearity has been measured with quasi-dynamic stepwise triangular waveforms at frequencies between 0.5 Hz and 1 kHz. None of the digitizers outperforms all others for each tested characteristics. Therefore, such a systematic characterization provides the overview needed to identify the most suitable digitizer for a given application. [ABSTRACT FROM AUTHOR]

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]