Synthesis of precision AC waveforms using a SINIS Josephson junction array
ABSTRACT A synthesizer of precision AC waveforms based on a SINIS Josephson junction array has been developed. The array is divided into 15 segments in a binary series and the segments are individually biased using a high speed bias source with a 100 ns rise time. The design considerations and accuracy limitations of the system are discussed and comparisons between the synthesizer and thermal converters are presented.
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ABSTRACT: Voltage pulses with a determined amplitude and width might be the basis for high-precision ac voltage measurements in the future. The pulse width modulation technique makes possible the generation of arbitrary waveforms. In this paper, arrays of SINIS Josephson junctions were investigated which produce a 1 V voltage step under irradiation at a frequency of the order of 70 GHz. This step has an amplitude of 1 mA whereof a region of 0.3 mA overlaps with the critical current. This allows the generation of a 1 V voltage pulse by switching the microwave power at constant dc bias current. The results of this investigation will be presented and also the array parameters which are required for obtaining a relative uncertainty of 0.1 ppm in ac voltage measurements.IEEE Transactions on Applied Superconductivity 07/2005; DOI:10.1109/TASC.2005.849833 · 1.32 Impact Factor
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ABSTRACT: The electrical characteristics of two different 1-V binary programmable Josephson arrays, an superconductor/insulator/normal conductor/insulator/superconductor-type Josephson array, and an externally shunted superconductor/insulator/superconductor-type Josephson array, were investigated at ten metrology institutes. Various operational parameters were evaluated and compared using different Josephson array voltage standard setups at microwave frequencies around 70 GHz. The results of the measurements show that both arrays have been working very well and the main differences were not imposed by the arrays themselves, but by the different measurement setups of the laboratories.IEEE Transactions on Instrumentation and Measurement 05/2003; DOI:10.1109/TIM.2003.811570 · 1.71 Impact Factor
Article: Josephson voltage standards[Show abstract] [Hide abstract]
ABSTRACT: This paper reviews the present state of modern Josephson voltage standards. The presentation focuses on conventional dc standards based on underdamped superconductor–insulator–superconductor junctions and programmable standards based on overdamped superconductor–insulator–normal conductor–insulator–superconductor junctions. The current developments of ac standards on the basis of pulse-driven arrays and single flux quantum-based voltage multipliers are briefly summarized.Measurement Science and Technology 07/2003; 14(8):1216. DOI:10.1088/0957-0233/14/8/305 · 1.35 Impact Factor