Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Multiple-quantum interference superconducting analog-to-digital converter. [Patent application]

R. Harris, C.A. Hamilton

Published May 7, 1981• 0 citations
OpenAlex

Abstract

Disclosed is an analog-to-digital converter using superconducting interferometers connected in parallel, each interferometer being identical. The coupling of the analog signal to each successive interferometer is increased in the ratio of 1:2:4:8:16:32:, etc. The application of a pulsed power supply to the parallel connected interferometer generates output voltages on the interferometers. The output voltages are a Gray Code representation of the analog signal.

Related papers

Multiple-quantum interference superconducting analog-to-digital converter

R. Harris, C.A. Hamilton, Frances L. Lloyd

Multiple-quantum interference in a superconducting interferometer is used for analog-to-digital conversion. The simple fully parallel four-bit converter which is described is the first known use of this effect in a digital circuit. Sampling rates of 2×108 per second were achieved, and much higher rates appear possible.

Applied Physics Letters•Nov 1, 1979•31 citations

Superconductor digital-to-analog converter based on processing of SFQ pulses

Vasili K. Semenov, P.N. Shevchenko, Yu. A. Polyakov

Recently we designed and successfully tested a prototype of a superconducting digital-to-analog converter (DAC) based on processing single flux quantum (SFQ) pulses. Two unique features make the device very attractive for metrology applications: (i) The generation of output voltage is based on the fundamentally accurate Josephson frequency-to-voltage relationship. (ii) The device does not require any external signals with frequencies higher than 100 MHz. It is expected that the DAC will be used as a key component of novel standards and calibrators of ac voltage with frequency up to 1 MHz. The implemented prototype has low magnitude of output voltage (about 10 mV) which is far lower than the 1 to 10 V target magnitude.

Conference on Precision Electromagnetic Measurements•Nov 27, 2002•9 citations

An optically coupled superconducting analog to digital converter

Lewis A. Bunz, R. P. Robertazzi, Sergey V. Rylov

A superconducting analog-to-digital converter has been coupled with a laser diode also operating at 4.2 K to provide a serial output data stream via an optical fiber. The optical signal is converted to a room temperature electrical signal using standard optical fiber receiver techniques. After amplification these signals are fed into a fast comparator circuit. The output of the comparator is a TTL level signal suitable for connection to conventional electronic equipment.

IEEE Transactions on Applied Superconductivity•Jun 1, 1997•6 citations

Using Analog-to-Digital Converters to Increase the Efficiency of Digital Antenna Arrays

Vasyl M. Kychak, M.I. Ursan, O.Melnychuk O.Melnychuk

Analog-to-digital converters of radio signals, which are based on the phenomenon of superconductivity and the Josephson effect, are proposed to use in order to increase the efficiency of digital antenna arrays. Digital beamforming systems were analysed. Application of the proposed approach was shown to promote processing signals directly at carrier frequencies in the SHF and EHF bands. This approach allows to exclude frequency mixers, local oscillators and intermediate frequency filters from a receiving module. A parallel scheme with comparators on superconducting quantum interferometers is proposed for constructing a superconducting ADC. A digital Gray code is formed at the output of the ADC. The proposed scheme being utilizing, when the input signal increases, each comparator passes through several thresholds, and if Gray codes are applied, only one of the output bits changes between consecutive numbers. Therefore, Gray codes are less sensitive to errors that arise due to small differences in comparator’s thresholds. This promotes reduction of the bit error probability. As an outcome the performed analysis, it was shown that generators of single-quantum pulses on single Josephson junction with a hysteresis-free current-voltage characteristic can be used for constructing comparators, that provides obtaining a high time resolution. The dependence of time resolution on Josephson junction parameters, namely dielectric thickness, relative dielectric permeability and critical current density, was investigated. The resolution was shown to be equal units — tenths of a ns, and this allows using such devices for signal processing at frequencies of several hundred GHz. The time resolution changes with changes in the critical current density of a Josephson junction and in the dielectric thickness and it is almost independent on the relative dielectric permittivity. The sensitivity of the comparator on a single Josephson junction was evaluated. An analytical expression was obtained, it can be applied to estimate how parameters of the Josephson junction equivalent circuit, namely, electrostatic capacity, nonlinear conductivity, and critical current impact on the sensitivity of the comparator. The conducted studies showed that the sensitivity can be units of nA, which exceeds significantly the sensitivity of similar circuits based on semiconductors.

Visnyk of Vinnytsia Politechnical Institute•Jan 1, 2024•0 citations

Digital-to-analog converter using a superconducting quantum interference device

Masakazu Nakanishi

We developed a digital-to-analog converter (DAC) having a current output and incorporating a superconducting quantum interference device (SQUID). The linearity of the device is based on the periodic dependence of the SQUID response on the magnetic flux coupling to the SQUID ring. The period is a flux quantum (Φ(o) = h/2e, where h is Planck's constant and e is the elementary charge). Because of the device's quantum accuracy, the output is essentially linear. The SQUID DAC was constructed using a commercially available rf-SQUID, the periodicity of which has been experimentally verified below 3420 Φ(o). An adjustable number of current amplitudes are dependent on maximum output (I(max)). The output current is adjustable to ~100 000 different values when I(max) ~1 mA and ~1,000,000 when I(max) ~0.1 mA. The short-term fluctuation of ~0.15 ppm was attributable to flux resolution of the SQUID. As a demonstration, measurements showing the voltage linearity of a digital multimeter were performed.

Review of Scientific Instruments•Nov 1, 2012•3 citations

Note: Increasing dynamic range of digital-to-analog converter using a superconducting quantum interference device

Masakazu Nakanishi

Responses of a superconducting quantum interference device (SQUID) are periodically dependent on magnetic flux coupling to its superconducting ring and the period is a flux quantum (Φo = h/2e, where h and e, respectively, express Planck's constant and elementary charge). Using this periodicity, we had proposed a digital to analog converter using a SQUID (SQUID DAC) of first generation with linear current output, interval of which corresponded to Φo. Modification for increasing dynamic range by interpolating within each interval is reported. Linearity of the interpolation was also based on the quantum periodicity. A SQUID DAC with dynamic range of about 1.4 × 10(7) was created as a demonstration.

Review of Scientific Instruments•Oct 1, 2014•1 citation
Disclosed is an analog-to-digital converter using superconducting interferometers connected in parallel, each interferometer being identical. The coupling of the analog signal to each successive interferometer is increased in the ratio of 1:2:4:8:16:32:, etc. The application of a pulsed power supply to the parallel connected interferometer generates output voltages on the interferometers. The output voltages are a Gray Code representation of the analog signal.
Recently we designed and successfully tested a prototype of a superconducting digital-to-analog converter (DAC) based on processing single flux quantum (SFQ) pulses. Two unique features make the device very attractive for metrology applications: (i) The generation of output voltage is based on the fundamentally accurate Josephson frequency-to-voltage relationship. (ii) The device does not require any external signals with frequencies higher than 100 MHz. It is expected that the DAC will be used as a key component of novel standards and calibrators of ac voltage with frequency up to 1 MHz. The implemented prototype has low magnitude of output voltage (about 10 mV) which is far lower than the 1 to 10 V target magnitude.
Analog-to-digital converters of radio signals, which are based on the phenomenon of superconductivity and the Josephson effect, are proposed to use in order to increase the efficiency of digital antenna arrays. Digital beamforming systems were analysed. Application of the proposed approach was shown to promote processing signals directly at carrier frequencies in the SHF and EHF bands. This approach allows to exclude frequency mixers, local oscillators and intermediate frequency filters from a receiving module. A parallel scheme with comparators on superconducting quantum interferometers is proposed for constructing a superconducting ADC. A digital Gray code is formed at the output of the ADC. The proposed scheme being utilizing, when the input signal increases, each comparator passes through several thresholds, and if Gray codes are applied, only one of the output bits changes between consecutive numbers. Therefore, Gray codes are less sensitive to errors that arise due to small differences in comparator’s thresholds. This promotes reduction of the bit error probability. As an outcome the performed analysis, it was shown that generators of single-quantum pulses on single Josephson junction with a hysteresis-free current-voltage characteristic can be used for constructing comparators, that provides obtaining a high time resolution. The dependence of time resolution on Josephson junction parameters, namely dielectric thickness, relative dielectric permeability and critical current density, was investigated. The resolution was shown to be equal units — tenths of a ns, and this allows using such devices for signal processing at frequencies of several hundred GHz. The time resolution changes with changes in the critical current density of a Josephson junction and in the dielectric thickness and it is almost independent on the relative dielectric permittivity. The sensitivity of the comparator on a single Josephson junction was evaluated. An analytical expression was obtained, it can be applied to estimate how parameters of the Josephson junction equivalent circuit, namely, electrostatic capacity, nonlinear conductivity, and critical current impact on the sensitivity of the comparator. The conducted studies showed that the sensitivity can be units of nA, which exceeds significantly the sensitivity of similar circuits based on semiconductors.
We developed a digital-to-analog converter (DAC) having a current output and incorporating a superconducting quantum interference device (SQUID). The linearity of the device is based on the periodic dependence of the SQUID response on the magnetic flux coupling to the SQUID ring. The period is a flux quantum (Φ(o) = h/2e, where h is Planck's constant and e is the elementary charge). Because of the device's quantum accuracy, the output is essentially linear. The SQUID DAC was constructed using a commercially available rf-SQUID, the periodicity of which has been experimentally verified below 3420 Φ(o). An adjustable number of current amplitudes are dependent on maximum output (I(max)). The output current is adjustable to ~100 000 different values when I(max) ~1 mA and ~1,000,000 when I(max) ~0.1 mA. The short-term fluctuation of ~0.15 ppm was attributable to flux resolution of the SQUID. As a demonstration, measurements showing the voltage linearity of a digital multimeter were performed.
Responses of a superconducting quantum interference device (SQUID) are periodically dependent on magnetic flux coupling to its superconducting ring and the period is a flux quantum (Φo = h/2e, where h and e, respectively, express Planck's constant and elementary charge). Using this periodicity, we had proposed a digital to analog converter using a SQUID (SQUID DAC) of first generation with linear current output, interval of which corresponded to Φo. Modification for increasing dynamic range by interpolating within each interval is reported. Linearity of the interpolation was also based on the quantum periodicity. A SQUID DAC with dynamic range of about 1.4 × 10(7) was created as a demonstration.