We have developed a Johnson noise thermometry (JNT) system that is calibrated by precision waveforms synthesized with a quantized voltage noise source (QVNS). Significant improvements to the QVNS and the cross-correlation measurement electronics have dramatically 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 the Boltzmann constant.
Citation: IEEE Transactions on Instrumentation and Measurement
Pub Type: Journals
Noise, Correlation, Digital-analog conversion, Josephson arrays, Quantization, Signal synthesis, Standards, Superconductor-normal-superconductor devices, Johnson Noise, Boltzmann equation, Temperature, Measurement units.