Characterization of analogue-to-digital converters of a commercial digital voltmeter in the 20 Hz to 400 Hz frequency range

Abstract

This paper describes the result of work performed at the Laboratoire National de Métrologie et d'Essais (LNE) aiming at characterizing the metrological performance of analogue-to-digital converters of a commercial digital voltmeter in the 20 Hz to 400 Hz frequency range. In order to reach uncertainties at the 10−6 level, ac–dc thermal transfer techniques have been used to determine the most suitable sampling parameters for these digitizers with respect to the measured signal frequency. Under such conditions, the agreement between the sampling technique and thermal ac–dc transfer is of the order of 2 µV V−1.

Evaluation of Uncertainty of Phase Difference Determination in Presence of Bias

“…These sampling voltmeters have a high-resolution integrating ADC (IADC) that operates according to the dual slope principle. The sampling process is such that the sampling instant is not a discrete point in time, but the measured signal is integrated by IADC over the aperture time of AD converter [20][21][22][23][24][25][26][27].…”

Nouvelles possibilités d’étalonnage en puissance électrique au LNE

“…La caractérisation dynamique a été effectuée en comparant les mesures de la valeur efficace des signaux par les techniques d'échantillonnage aux mesures effectuées au moyen de convertisseurs thermiques [2]. On a défini l'erreur e AC comme la différence relative entre les valeurs mesurées par les deux techniques.…”

Traceability of Voltage Measurements for Non-Sinusoidal Waveforms

“…The ADCs of the DVM have already been characterized for static [4] and dynamic [5] conditions, for sine waves at frequencies up to 400 Hz. In this frequency range, selecting optimized sampling parameters, the agreement between the sampling technique and AC-DC transfer using thermal converters has been found better than 3 µV/V.…”

“…Taking into account the different sources of errors [5], the relative uncertainty (1σ) is estimated to be 3 µV/V at 50 Hz.…”