A synthesizer of precision ac waveforms based on a binary superconductor insulator-normal metal-insulator-superconductor (SINIS) Josephson junction array has been developed. The segments are individually biased using high-speed bias source which gives switching time approximately 250 ns between voltage steps. accuracy limitations the system due to limited risetime and bandwidth discussed. Comparisons planar multijunction thermal converter (PMJTC) indicate that it is possible synthesize sine...

Determinations of the conversion factor volt have been carried out after significant improvements to measuring system. The mean value 48 determinations was K/sub V/=1-0.02*10/sup -6/, with a standard deviation s/sub m/=0.064*10/sup -6/. corresponding frequency-to-voltage quotient is J/=483597.91 GHz/V. relative type B uncertainty experiment estimated be u=0.33*10/sup These data are preliminary, in as much recalibration standards used for capacitance, mass, and displacement terms SI units...

This paper reviews the present state of modern Josephson voltage standards. The presentation focuses on conventional dc standards based underdamped superconductor–insulator–superconductor junctions and programmable overdamped superconductor–insulator–normal conductor–insulator–superconductor junctions. current developments ac basis pulse-driven arrays single flux quantum-based multipliers are briefly summarized.

Josephson series arrays with a binary sequence of nonhysteretic superconductor-insulator-normal metal-insulator-superconductor (SINIS) junctions have been realized. The up to 8192 (14 bits) are operated at microwave frequencies about 70 GHz low power. An electronic system was built drive an automated dc quantum voltmeter. Two electrically isolated voltmeters (QVMs) in the same cryoprobe and driven by one frequency used for calibrating resistive dividers intention demonstrating some...

A description is given of the measuring system set up at PTB for realization SI volt and determination conversion factor Kv by means a voltage balance. The balance comprises two cylindrical electrodes to generate electrostatic force from 10.186 kV, substitution measure comparison with due gravity acting on 2 g mass. To achieve equilibrium small variable added constant voltage. generated in two-stage 1000-fold step-up linked asmaintained using transfer standard consisting 10 saturated cells...

The design of a new generation planar multijunction thermal converters (PMJTCs) on quartz membranes and crystal chips improves the frequency response PMJTC in range from 100 kHz to MHz allows decrease uncertainties. For heater resistance 1 kOmega ac-dc voltage transfer differences smaller than 5 muV/V are calculated for frequencies above up MHz. This is reduction more one order magnitude such high comparison PMJTCs with Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

An array of 7492 SINIS Josephson junctions was used to generate fast reversed dc (FRDC) voltages approximately 1.1 V for the study thermoelectric effects in planar multijunction thermal converters (PMJTCs). A bias current source reversal with a frequency up 10 kHz has been designed. For first time, results measurements on two different PMJTCs excellently agree obtained using semiconductor FRDC within 0.06 /spl mu/V/V 200 Hz. At higher frequencies, systematic slope relative FRDC-DC voltage...

The ac-dc current transfer standards at PTB have been improved in frequency and range up to 1 MHz A using a newly designed transconductance amplifier. Up 100 kHz 10 A, the uncertainties could be dramatically reduced. Starting from calculable quartz planar multifunction thermal converter 30 mA, for currents new shunts with small level dependence an measurement set-up are used

To determine arbitrary resistance ratios with high precision, a measuring system based on dual Josephson voltage standard has been set up. It is demonstrated that, by means of this system, 10-k/spl Omega/ resistors can be linked to quantized Hall (i=2, 12.9 k/spl Omega/) an expanded uncertainty (k=2) less than 4 parts in 10/sup 9/.

A correlation method is described for analysis of electrical impedances. The impedance investigated as part a four-terminal network, allowing general system techniques to be applied. With pseudorandom noise signal input the measured cross-correlation function corresponds, under certain conditions, impulse response network and contains information about components via time constants network. has been applied two-terminal networks liquid capacitor filled with solution poly- gamma...

An array of 7492 SINIS Josephson junctions was used to generate fast reversed dc (FRDC) voltages approx. 1.1 V for the study thermoelectric effects in planar multijunction thermal converters (PMJTC). A bias current source reversing with a frequency up 10 kHz has been designed. First measurements PMJTC have shown slope FRDC-DC voltage transfer difference versus about 10/sup -8//Hz. Regression zero allows be determined an uncertainty less than 0.1 /spl mu/V/V.

The low-frequency AC-DC voltage transfer differences of thermal converters for higher voltages with planar multijunction (PMJTCs) and series resistors have been determined by using only the assumption a linear change current difference PMJTC input power. Uncertainties less than 1 /spl mu/V/V are achieved up to 1000 V.

Ac-dc transfer at PTB is performed using planar multijunction thermal converters. Scaling used to calibrate standards for different voltage and current levels with calculable converters on a quartz substrate as reference. The number of steps in the scaling could be significantly reduced by exploiting full dynamic range which led lower overall uncertainties. Applying ranges instead single point values measurement well frequencies drastically simplified tables showing best capabilities.

A precise realization of the unit capacitance is important for determination both Josephson and von Klitzing constants. The main design criteria PTB's cross capacitor, maintenance over last 10 years, a special capacitance-measuring bridge tracing back electrode in absolute volt experiment to SI units are described this paper.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Comparisons of the 10 V Josephson array voltage standard (JAVS) Bureau International des Poids et Mesures (BIPM) were made at Physikalisch-Technische Bundesansalt (PTB), Braunschweig, Germany with those PTB and Swedish National Testing Research Institute (SP), Boras, Sweden, in January 1998. Although results agree within an overall uncertainty less than one part 10/sup 9/, a small but interesting dependence on microwave power was observed dc output array.

Work on an electrostatic measuring system for the determination of SI volt and conversion factor KV at PTB is reported. The consists a so-called voltage balance generator dc voltage. There need development such device with uncertainty below 1 part in 106 because measurements existing balances, results obtained by other methods show discrepancies several parts 106. In order to reduce simplify apparatus special method was developed. voltage/force transducer formed from two coaxial cylindrical...

The new generation of PMJTCs on quartz crystal chips and membranes developed at the Physikalisch-Technische Bundesanstalt (PTB) results in calculable ac-dc current transfer standards for a 10 mA frequency range from kHz to 1 MHz, with considerably reduced uncertainties. AC-DC differences below /spl mu/A/A standard uncertainties have been achieved.

Millivolt ac-dc transfer devices and ac measuring instruments are calibrated with new micropotentiometers (mupots) low output impedance. Newly designed resistors of 0.2 0.1 Omega lead to reduced load corrections for 150 kOmega input impedance amplifiers only a few muV/V. The higher current required is measured at 1 MHz 500 mA thermal converter. At MHz, expanded uncertainties (k = 2) less than 40 muV/V achieved from 100 down 10 mV

This paper describes an improved Josephson Arbitrary Waveform Synthesizer (JAWS) at PTB. The improvements led to a more user-friendly JAWS system with lower complexity. arrays which deliver pure sine wave spectrum have been developed. Preliminary measurements of AC-AC differences in the frequency range from 125 Hz 20 kHz are presented.

Comparisons of the 10 V Josephson array voltage standard (JAVS) Bureau International des Poids et Mesures (BIPM) were made at Physikalisch-Technische Bundesansalt (PTB), Braunschweig, Germany with those PTB and Swedish National Testing Research Institute (SP), Boras, Sweden, in January 1998. Although results agree within an overall uncertainty less than 1 part 10/sup 9/, a small, but interesting, dependence on microwave power was observed DC output one array.

This paper describes an automatized capacitance bridge (KRMS-C) developed for calibration of dielectric loss capacitors in the wide range from 10 nF up to mF at frequencies 50 Hz kHz. The system is based on technique, where voltage drops across known and unknown impedance are measured when measurement conditions fulfilled, value can be evaluated. arrangement KRMS-C allows performing 4-TP with appropriate adaptors also 3-T 5-T capacitors. Due integrated scanner/multiplexer, four possible a...

The input characteristics of a two-channel high speed digitizer have been improved utilizing accurate and matched instrumentation amplifiers the complete system has characterized. DC linearity stability investigated correction function for digital filter formed up to 35% its sampling frequency.

New micropotentiometers (/spl mu/pots) have been built with planar multijunction thermal converters (PMJTC) on Si- and SiO/sub 2/-substrates, new disc resistors redesigned housings. The step down from 100 mV to 2 can be performed only two /spl mu/pots. millivolt-amplifiers gain factors of 11, 50, 121 in conjunction PMJTCs are developed measure the output voltage mu/pots mV. Their high input impedance >1 M/spl Omega/ par/ < 6 pF avoids loading resistor These systems lead considerable...

New millivolt-amplifiers (mV-amplifiers) driving planar multijunction thermal converters (PMJTCs) at their output have been developed to measure the voltage of micropotentiometers (mupots). Using a twin-stage design with gains 10, 20, and 30 per stage, total gain factors ranging from 10 900 are achieved. This results in usable range input voltages 100 muV up mV frequencies dc 1 MHz. A novel offset compensation small reversal differences, this allows for reliable operation higher factors....

In an extension from their original use as references for measuring dc voltage, Josephson generated voltages programmable arrays have been employed to measure waveforms differentially. this paper, the alternative of using these a reference ac-dc difference measurements thermal converters and sampling techniques is presented.