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TitleImprovements in the NIST Johnson noise thermometry system
Publication TypeJournal Article
Year of Publication2009
AuthorsBenz, S.P., Qu J., Rogalla H., White D.R., Dresselhaus P.D., Tew W.L., and Nam S.W.
JournalIEEE Transactions on Instrumentation and Measurement
Pagination884 - 890
Date Published2009
ISSN00189456 (ISSN)
KeywordsAcoustic noise measurement, Boltzmann equation, Boltzmann's equation, Control nonlinearities, Correlation, Digital-analog conversion, Frequency response, Josephson arrays, Measurement units, Measurements, Noise measurement, Quantization, Signal synthesis, Synthesis (chemical), Systematic errors, Temperature measurement, Temperature sensors, Thermometers, Uncertainty analysis, Units of measurement
AbstractWe have developed a Johnson noise thermometry (JNT) system that is calibrated by precision waveforms synthesized with a quantized voltage noise source (QVNS). Improvements to the QVNS and the cross-correlation measurement electronics have significantly reduced systematic errors and measurement uncertainty. We describe in detail a number of these improvements, such as amplifier performance and frequency response. We also show details of recent measurements that characterize the nonlinearities and distortion properties of the measurement electronics. Finally, we present an uncertainty analysis and discuss the potential for the QVNS-JNT technique to contribute to the redefinition of Boltzmann's constant. © 2008 IEEE.

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