- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Uncertainty analysis for ac–dc difference measurements with the AC Josephson voltage standard
摘要： A detailed analysis of the uncertainties obtained in ac–dc difference measurements with an AC Josephson voltage standard (ACJVS) is presented. For audio frequencies and for voltages less than 200 mV, ac–dc transfers with the ACJVS may reduce the combined uncertainty by factors of 2–10, compared with conventional methods based on thermal converters. Type A uncertainties are predominantly limited by the thermal transfer standard (TTS), or the digital voltmeter used to acquire the output voltage from the TTS. In agreement with earlier work, the transmission line is the primary contributor to Type B errors for frequencies above 10 kHz. A Monte Carlo sensitivity analysis is used to demonstrate how the uncertainties of transmission line impedance and on-chip inductance impact the accuracy of the rms amplitude conveyed to the TTS.
关键词： ac voltage metrology,transmission line analysis,Josephson junction arrays,quantum voltage standards,uncertainty analysis
更新于2025-09-23 15:22:29
-
[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Fabrication and characterization of physically-linked large-scale josephson junction test arrays
摘要： The efforts of National Institute of Metrology (NIM) towards large scale Nb/ NbxSi1-x /Nb Josephson junction arrays for the quantum voltage standards are presented in this paper. Physically-linked arrays with 10,000 and 20,000 junctions (corresponding to 1 and 2 junctions vertically) are fabricated. DC I-V characteristics of different stacked arrays are measured and experimental results are discussed. Focusing ion beam (FIB) together with scanning electron microscope (SEM) are used to examine the cross-section of three types of junction stacks which vertically contains 2, 3, and 4 junctions respectively. It is shown that grain boundary defects in the niobium wiring layer exist for all of these junction stacks. A method which potentially could solve this problem is proposed.
关键词： superconducting device fabrication,Josephson junctions,quantum voltage,superconducting
更新于2025-09-23 15:22:29
-
[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Study on the phase shifter in josephson junctions embedded microwave circuits
摘要： In a programmable Josephson voltage standard device which contains multiple branches of Josephson junction (JJ) array, the microwave reflection in arrays may result in a decrease in the Shapiro step margin. According to most of the previous designs, 90° phase shifter is used to cancel microwave reflection from branches to improve the performance of the device. This paper reports our study of the phase shifter in JJ array device with a 2-stage Wilkinson power divider. At first we designed and fabricated JJ array circuits with the phase shifters. Measurement results indicate that unequal powers have been reached to arrays. We then deleted the phase shifters in another design. Identical Shapiro step margins for 4 JJ array branches are achieved.
关键词： phase shifter,Josephson junctions,quantum voltage,superconducting
更新于2025-09-23 15:22:29
-
[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Frequency-Dependent Verification of the Quantum Accuracy of a Quantum Voltage Noise Source
摘要： This paper describes the characterization of a quantum voltage noise source (QVNS) based on pulse-driven Josephson-arrays for frequencies up to 200 kHz. The QVNS synthesizes a voltage noise reference which is used to calibrate the electronics of a Johnson noise thermometer (JNT). To realize an “electronic Kelvin” with measurement uncertainty at μK/K-level, we investigated the frequency-dependent voltage difference between two pulse-driven Josephson Arrays, each one producing a 10 mV RMS sinusoidal voltage.
关键词： Josephson arbitrary waveform synthesizer,quantum voltage noise source,Josephson voltage standard
更新于2025-09-10 09:29:36
-
[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - AC Voltage Measurements up to 120 V with a Josephson Arbitrary Waveform Synthesizer and an Inductive Voltage Divider
摘要： We use a precision inductive voltage divider and a lock-in amplifier to extend the voltage range of a Josephson arbitrary waveform synthesizer with a maximum voltage of 250 mV rms to provide accurate voltage measurements up to 120 V. Experimental results show that the output of the JAWS can be extended to high voltages with uncertainties of a few microvolts per volt or less, depending on the voltage amplitude and frequency.
关键词： quantum voltage standards,measurement array,Inductive voltage divider,standards,Josephson junction techniques
更新于2025-09-10 09:29:36
-
[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Josephson Arbitrary Waveform Synthesizer as a Reference Standard for the Measurement of the Phase of Harmonics in Distorted Signals
摘要： We use the Josephson arbitrary waveform synthesizer to provide traceability for the phase of the harmonics, relative to its fundamental, of a distorted waveform. For distorted waveforms with rms values in the range from 0.154 V to 0.2 V and harmonic magnitudes from 5% to 40 % of the fundamental, our system can generate odd harmonics up to the 39th with phase uncertainties from 0.002° to 0.010° (k=2.0), depending on the harmonic number and harmonic magnitude.
关键词： Josephson junction array,measurement techniques,measurement quantum voltage standards,standards,phase measurement,spectrum analysis
更新于2025-09-10 09:29:36