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.

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Cette publication présente la réalisation d'un nouvel étalon de puissance à partir d'une sonde à thermocouple commerciale. Un étalonnage au microcalorimètre a été effectué afin de déterminer l'efficacité effective de la sonde. Un étalonnage par la méthode de transposition thermique a contribué à valider les résultats obtenus au microcalorimètre. Le LNE s'est doté ainsi d'un nouvel étalon de puissance pour les basses fréquences.

This paper describes the result of work performed at the Laboratoire National de Métrologie et d'Essais (LNE) aiming at developing a standard system to measure RMS value and harmonic contents of distorted voltage waveforms by means of a sampling voltmeter. Thermal converters are used to trace the RMS value to the SI units. The error of the DVM has been generally found less than 10 µV/V up to 2 kHz but can reach about 50 µV/V at 2.5 kHz for RMS voltage measurements for sine waves. For distorted waveforms, deviations within 15 µV/V have been obtained whatever the total harmonic distortion of the waveforms.

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