Combining Josephson Systems for Spectrally Pure AC Waveforms With Large Amplitudes

Behr, R.; Kieler, Oliver; Schleubner, Detlef; Palafox, L.; Ahlers, F. J.

doi:10.1109/tim.2013.2238433

Cited by 15 publications

(13 citation statements)

References 24 publications

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“…4 presents the result for (9) and Fig. 5 the results for (8) and (9). The decibel SINAD error in Figs.…”

Section: B Simulations To Determine Correct Measurement Filter Gain mentioning

confidence: 97%

“…European Metrology Institutes have approached this problem by employing superconducting techniques to produce a Josephson Junction based DAC through the Q-wave project [6]. Publically available results so far indicate that the theoretical limit of an ideal low-order delta sigma DAC may have been achieved [7], [8]. Superconducting bandpass filters are used in mobile communications base stations and offer a further way to reduce THD [9].…”

Section: Measuring Effective Number Of Bitsmentioning

confidence: 99%

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ADC Standard IEC 60748-4-3: Precision Measurement of Alternative ENOB Without a Sine Wave

Belcher

2015

IEEE Trans. Instrum. Meas.

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A practical analog-to-digital converter (ADC) introduces quantization error in excess of the ideal value and one way of expressing this is by comparing the value of this error with that of an ideal ADC. This comparison is known as the effective number of bits (ENOBs). It is accepted practice to measure ENOB using the signal-to-noise and distortion (SINAD) ratio of a sine-wave input. This paper extends ENOB theory to any arbitrary waveform by including the crest factor of the input signal. It is now possible to apply the ENOB concept to wideband systems. Measuring the SINAD of an arbitrary or multitone waveform with precision normally requires the use of laboratory standard test equipment. However, International Electrotechnical Commission standard 60748-4-3 specifies an alternative method for wideband SINAD measurements that may also be suitable for built-in test. It is essentially a multitone test using two pseudorandom signal sources and is sometimes known as the double comb-filter (DCF) method. This paper demonstrates the requirements for a practical implementation of a DCF-based system for measuring an ENOB of up to 24 bits. It is shown that in a practical application, DCF ENOB and sine-wave ENOB results have similar levels of accuracy, but in the presence of amplitude nonlinearity the differing test signal amplitude weightings cannot fundamentally produce the same ENOB figure. It is shown that DCF ENOB is more representative of communications system performance and therefore extends the use of ENOB to wideband applications.

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“…4 presents the result for (9) and Fig. 5 the results for (8) and (9). The decibel SINAD error in Figs.…”

Section: B Simulations To Determine Correct Measurement Filter Gain mentioning

confidence: 97%

Section: Measuring Effective Number Of Bitsmentioning

confidence: 99%

ADC Standard IEC 60748-4-3: Precision Measurement of Alternative ENOB Without a Sine Wave

Belcher

2015

IEEE Trans. Instrum. Meas.

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“…It is noted that Behr et al [27] used a PJVS and PD JJAs to generate pure ac waveforms, which is similar in some respects but has significant differences with the approach presented in this paper. In [27], the PJVS chip must have a number of operational CWD JJAs to produce a stepwise approximated waveform.…”

Section: Introductionmentioning

confidence: 96%

Quasi-continuous dc voltage standard using sinusoidal and pulse-driven Josephson junction arrays

Georgakopoulos¹,

Budovsky²,

Benz³

2022

Meas. Sci. Technol.

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Josephson voltage standards (JVSs) provide a primary realization of the volt, the unit of electromotive force. They generate direct (dc) voltages up to 10 V and show agreement better than 1 nV/V at 10 V. For JVSs based on Josephson junction arrays (JJAs) that are driven by sinusoidal radiofrequency (RF) power, commonly referred to as continuous wave-driven JJAs (CWD JJAs), the minimum voltage that can be generated is limited to the voltage across one Josephson junction for practical devices. To achieve this resolution, they may require a perfect JJA chip. JVSs based on a pulse-driven (PD) JJA require high performance electronics (i.e., high bandwidth, low distortion and jitter, pulse shaping filters and large memory) to achieve their minimum and maximum voltage. We have combined two CWD JJAs and two PD JJAs driven by two microwave inputs to one chip to generate quasi-continuous dc voltages up to the sum of the full-scale voltages of both JJAs that are robust to the imperfections of the Josephson junctions and have relaxed requirements on the radio frequency (RF) electronics driving the JJA, compared to the existing CWD JVSs and PD JVSs, respectively. By use of the JJA chip at the National Measurement Institute Australia, we demonstrate its feasibility to generate voltages up to 1 V. Preliminary evaluation of the system shows that the voltage uncertainty can be 11 nV (k=2) or better and the theoretical resolution is better than 1 nV from 0 V to 1 V. The main requirement is that all the Josephson junctions must have quantum locking ranges with respect to the power and frequency of the RF bias and for the PD JJAs to have a constant voltage over a range of dc bias current. Although this development is not a replacement for existing state-of-the-art JVSs, we anticipate that it will be an alternative fit-for-purpose solution for metrological applications under non-ideal operating conditions or when the components of the state-of-the-art solutions are not available.

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“…Nearly two decades of research and development by numerous technologists, metrologists, laboratories, and international research programs have been applied to this goal and to turning the devices into practical systems for calibrating ac voltage standards and other instruments [4]- [37]. In addition to enabling significant improvements in ac voltage metrology at rms voltages of 1 V and below, this system will act as a quantumbased reference for the entire parameter space of the National Institute of Standards and Technology (NIST)'s ac voltage calibrations [38].…”

Section: Introductionmentioning

confidence: 99%

“…Stepwise-approximated ac voltage waveforms can be generated by programmable Josephson voltage standards with a 7 V rms output. However, the nonquantum behavior of the transitions between the steps prevents these waveforms from having intrinsically accurate ac voltages ( [13]- [15], [37]). …”

Section: Introductionmentioning

confidence: 99%

One-Volt Josephson Arbitrary Waveform Synthesizer

Benz

Waltman²,

Fox

et al. 2015

IEEE Trans. Appl. Supercond.

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A quantum-accurate waveform with an rms output amplitude of 1 V has been synthesized for the first time. This fourfold increase in voltage over previous systems was achieved through developments and improvements in bias electronics, pulse-bias techniques, Josephson junction array circuit fabrication, and packaging. A recently described ac-coupled bipolar pulse-bias technique was used to bias a superconducting integrated circuit with 25 600 junctions, which are equally divided into four series-connected arrays, into the second quantum state. We describe these advancements and present the measured 1 V spectra for 2 Hz and 10 Hz sine waves that remained quantized over a 0.4 mA current range. We also demonstrate a 2 kHz sine wave produced with another bias technique that requires no compensation current and remains quantized at an rms voltage of 128 mV over a 1 mA current range. Increasing the clock frequency to 19 GHz also allowed us to achieve a maximum rms output voltage for a single array of 330 mV.

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Combining Josephson Systems for Spectrally Pure AC Waveforms With Large Amplitudes

Cited by 15 publications

References 24 publications

ADC Standard IEC 60748-4-3: Precision Measurement of Alternative ENOB Without a Sine Wave

ADC Standard IEC 60748-4-3: Precision Measurement of Alternative ENOB Without a Sine Wave

Quasi-continuous dc voltage standard using sinusoidal and pulse-driven Josephson junction arrays

One-Volt Josephson Arbitrary Waveform Synthesizer

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