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This paper describes a compact, portable, high-precision voltage standard based on 1 V programmable Josephson array. The accuracy of the system is estimated to be better than 4 nV. The system can realize the fully automatic measurement of voltage reference, as well as its weight and volume are reduced. "In August, 2007 this system was carried to PTB, Germany to make a comparison. The difference...
We have performed an experiment to drive an over-damped Josephson junction array (JJA) with modulated current pulse trains, which are generated by a modulated optical comb (an ultra-short pulse laser). The intensities of optical pulse trains are modulated using a pulse pattern generator. We quantitatively verified that the output voltages of the JJA were consistent with the modulation signals.
A waveform synthesizer adopting a programmable Josephson voltage standard has been developed, which can produce stepwise sinusoidal waveforms with few hundred quantum voltage levels. For synthesis of waveforms, individual cells on the Josephson array chip were promptly biased using a 7-channel current source with 14-bit resolution. As an application, the synthesizer was utilized as a fast-reversed...
This paper describes the influence of the bias current on transients when synthesizing an AC signal using a programmable Josephson voltage standard. Measured changes of the RMS value of synthesized signals are compared with the presented model.
NIST is designing a 10 V Programmable Josephson Voltage Standard (PJVS) system with an improved microwave design and arrays of stacked NbxSi1-x-barrier Josephson junctions. For this new design a "ground-up" approach was used that takes into account all system issues in order to produce a robust 10 V system. By improving the uniformity of the microwave drive along the length of each array,...
In 2007 the CCEM proposed changes in the SI electrical units (Recommendation E-1), which has refocused attention on the validity and accuracy of the Josephson effect. We review comparisons of Josephson effect voltage standards and summarize the results as they pertain to the accuracy of the Josephson relationship between voltage and frequency. We also report a list of possible influence parameters...
We report operation of a programmable Josephson voltage standard on a closed-cycle refrigerator. NIST IV PJVS chip is used, and we operate the chip with the fingerboard that is adopted from the existing liquid helium dipping probe. We demonstrate operation at 5.5 K of chip temperature, with a flat Shapiro step in the sub-array of the chip.
In December 2007, a comparison of the 10 V Josephson Array Voltage Standard (JAVS) of the LNE was performed with that of the BIPM in the framework of BIPM.EM-KlO.b comparison. During the week allotted to the exercise, the measurement setup was optimized to achieve a relative voltage difference of 7times10-12 within a relative Type A uncertainty of 8times10-12. We then took the opportunity to carry...
In this paper the setting up of a binary Josephson array waveform system for synthesization of arbitrary waveforms is described. The authors are with the Electricity Laboratory in the Metrology and Calibration Centre of INTA (Instituto Nacional de Tecnica Aeroespacial) in Torrejon de Ardoz, Madrid, Spain.
NIST recently reported the first application of a quantum AC Josephson voltage standard (ACJVS) for calibration of thermal transfer standards in the 1 kHz to 10 kHz frequency range. This paper describes preliminary work on extending its frequency calibration range up to 100 kHz by correcting systematic errors due to voltage leads.
We have been operating a 10-V programmable Josephson voltage standard (PJVS) system that was developed based on a multi-chip technique. We compared the PJVS with an SIS-based conventional JVS indirectly using a zener diode. The results agreed within 10-8 level.
Sampling is a promising technique for comparing the stepwise-approximated sine waves synthesized by an AC Programmable Josephson Voltage Standard to the sinusoidal voltages of a secondary source at low frequencies (a few hundred hertz or less). This paper describes a differential method that uses an integrating sampling voltmeter to precisely determine the amplitude and phase of high purity sine wave...
This paper describes an DC voltage calibration system which is improved to be more accurate and more easy to operate. It is based on 10 V Josephson array, and uses a fully automated system consisting of switches setup well designed for accurate measurement. An overall standard uncertainty is estimated less than 5 nV(1sigma) at 10 V level.
We have measured stepwise-approximated sinewaves generated by a programmable Josephson voltage standard with several different output configurations. These data are analyzed to characterize the dominant error mechanisms for rms applications, such as ac-dc difference measurements of a thermal voltage converter (TVC). We discuss the impact of the dominant systematic errors on the overall uncertainty...
We describe measurements with a pulse-driven AC Josephson voltage standard (ACJVS) that uses a ternary arbitrary bitstream generator as the bias source. From these measurements we conclude that the circuit is operational for voltages up to 220 mV rms. We present a measured spectrum and operating margins for different voltages.
The AC quantum voltmeter, an instrument for measuring AC waveforms by comparing them to a Josephson waveform, has been enhanced. Two different improvements to the signal-to-noise ratio are presented. The signal amplitude has been significantly increased by using 10-V Josephson arrays. The noise contribution has been reduced by adding a preamplifier at the input of the sampling null detector.
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