Compensation of Digital Voltmeters Nonlinearities by means of a Quantum Standard |
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| Andrea Sosso, Roberto Cerri |
- Abstract:
- The high linearity and stability of modern top-level Digital Voltmeters (DVM) can be exploited to measure voltage ratios with very low uncertainty by making two separate absolute voltage measurements. Yet, to obtain the very low uncertainties required to use a DVM as a voltage ratio standard, the intrinsic linearity of the instrument is not sufficient and techniques to determine and correct the residual non linearities must be adopted.
The Josephson Array Voltage Standard (JAVS) is well known as a voltage standard with nearly ideal accuracy. JAVS can can be also used for voltage ratio calibration, provided a source with high short- term stability is available. JAVS are then the best way to measure the very small linearities of a DVM, being the short-term requirement generally fulfilled by high quality voltmeters.
We performed several measurements for the evaluation of the linearity of DVMs in use in our laboratories, aimed at determining the performances of commercial multimeters as voltage ratio standards for the dissemination of the volt and for replacing ordinary techniques based on resistive dividers in primary metrology. The results appear to be encourag- ing for both applications: after calibration, uncertainty below 0.1 ppm can be obtained, with a stable profile of non linearity correction over time. - Keywords:
- Digital Voltmeters, Josephson Array, Voltage Standard, Linearity, Voltage Ratio
- Download:
- IMEKO-IWADC-2003-27.pdf
- DOI:
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