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

Superconducting modulators for analog-to-digital converters

Peter Magnusson

Published Jan 1, 2005• 1 citation
OpenAlex

Abstract

The main topic of this thesis is the evaluation of performance of super-conducting rst- and second-order low-pass sigma-delta modulators. Superconducting electronics comprise characteristics such as very high switching speed, natural quantization, high sensitivity and low noise, proper-ties that are all essential for modulators used in high performance analog-to-digital converters (ADC). Sigma-delta modulators trade speed for improved resolution using feedback mechanisms making superconducting electronics an interesting alternative technology for the implementation. With linear models and device-level simulations the performance of these modulators have been evaluated. The linear model of the rst-order sigma-delta modulator shows that the performance, for a given oversampling ratio, only depends on the cut-o frequency of the RL-lter used. This is veried by device-level simulations and the results from the two methods are in good agreement. Device-level simulations of the second-order sigma-delta modu-

Related papers

Superconducting modulators for high dynamic range delta-sigma analog-to-digital converters

A. Hodge Worsham, Donald L. Miller, Paul D. Dresselhaus +2 more

Superconducting digital circuits are capable of producing high dynamic range analog-to-digital converters (ADCs). We present sigma-delta architectures using large (>100) oversampling ratios to give signal-to-noise ratios of greater than 100 dB in simulation. Three distinct designs, using two distinct mechanisms for feedback, are presented. All of the designs use only shunted junctions, and are therefore compatible with HTS SNS junctions. Simulations are presented for a modulator which creates feedback pulses by SQUID lobe-crossings, a modulator which uses the transresistance of a SQUID for feedback, and a modulator which uses threshold crossings in both the first and second loops for feedback.

IEEE Transactions on Applied Superconductivity•Jun 1, 1999•26 citations

Superconducting second-order sigma-delta modulators utilizing multi-flux-quantum generators

T. Hashimoto, H. Hasegawa, Shuichi Nagasawa +3 more

We have been developing a superconducting second-order sigma-delta analog-to-digital converter with a large bandwidth and a large dynamic range for software radio applications. In a superconducting second-order sigma-delta modulator utilizing a passive integrator and single-flux-quantum (SFQ) feedback, gain to compensate the large attenuation in the passive integrator of the modulator is required to obtain a large dynamic range. In this paper, a second-order modulator utilizing multi-flux-quantum (MFQ) generators creating the needed gain is reported and the design and experimental test results of the elementary circuits including a comparator, a first-order modulator, and the MFQ generator are described. The digital outputs of the comparator and the first-order modulator were experimentally evaluated, where the input dependence of the comparator switching probability and the noise-shaping properties of the modulator were clearly observed. The low speed operation of the MFQ generator creating three SFQ pulses was experimentally confirmed. The other circuits were also tested at low frequencies.

IEEE Transactions on Applied Superconductivity•Mar 1, 2001•12 citations

A Quantum-Accurate Two-Loop Data Converter

Quentin Herr, Donald L. Miller, Aaron A. Pesetski +1 more

High performance oversampling delta-sigma data converters require high clock rates and accurate feedback of the digital output to the analog regime. Superconductor modulators offer the unique advantages of clock rates in the tens-of-gigahertz, comparator switching energy below attoJoules, and quantum-accurate digital-to-analog feedback. We have designed a two-loop baseband modulator whose noise transfer function was calculated using a simple, linear circuit model. The circuit was fabricated in a commercial superconductor IC process with 4.5 kA-per-square cm Josephson junctions and 1.5 micron minimum feature size. The circuit was tested at a derated sample rate of 5 GHz. Measured signal-to-noise dynamic range was 81 dB over a 10 MHz band. Third-order intercept was measured to be +24 dBsat in two-tone test. The measured noise transfer function was in excellent agreement with our linear model. The linear model indicates that with appropriate parameter values, this family of modulators extrapolates to significantly higher performance.

IEEE Transactions on Applied Superconductivity•Jun 1, 2009•6 citations

Superconductor analog-to-digital converters and their applications

Deepnarayan Gupta, Amol Inamdar, Dmitri E. Kirichenko +2 more

A wide variety of applications, ranging from radio-frequency (RF) receivers for broadband communications and signal detection, on earth and in space, would benefit from high-performance superconductor analog-to-digital converters (ADCs), based on magnetic flux quantization and fast switching Josephson junctions. Superconductor ADCs are capable of very high sample rates (100 GHz or more), very high linearity, and high sensitivity. Nyquist-rate ADCs use the high sample rate to digitize a wide instantaneous bandwidth (tens of GHz) and are useful for wideband spectrum monitoring as well as high-end scientific instrumentation. Delta and delta-sigma oversampling ADCs use the high linearity to achieve programmable trade-off between dynamic range and instantaneous bandwidth. These lowpass and bandpass ADCs have been used for direct digitization of narrower (tens to hundreds of MHz) RF bands in the 1-20 GHz range for a variety of communications, intelligence, electronic warfare, and radar applications. Another application area of these cryogenic ADCs is for outputs of cryogenic sensor arrays and terahertz mixers. Recent advances in various classes of ADCs for different applications are described.

IEEE MTT-S International Microwave Symposium digest•Jun 1, 2011•21 citations

Superconductor analog-to-digital converters

Oleg A. Mukhanov, Deepnarayan Gupta, Alan M. Kadin +1 more

Ultrafast switching speed, low power, natural quantization of magnetic flux, quantum accuracy, and low noise of cryogenic superconductor circuits enable fast and accurate data conversion between the analog and digital domains. Based on rapid single-flux quantum (RSFQ) logic, these integrated circuits are capable of achieving performance levels unattainable by any other technology. Two major classes of superconductor analog-to-digital converters (ADCs) are being developed - Nyquist sampling and oversampling converters. Complete systems with digital sampling at rates of /spl sim/20 GHz and above have been demonstrated using low-temperature superconductor device technology. Some ADC components have also been implemented using high-temperature superconductors. Superconductor ADCs have unique applications in true digital-RF communications, broadband instrumentation, and digital sensor readout. Their designs, test results, and future development trends are reviewed.

Proceedings of the IEEE•Sep 20, 2004•185 citations

Superconducting Analog to Digital Converters

Joel M. Schoen

Contents: Superconducting Analog-to-Digital Converter Work at MITRE; Development of a Rapidly Tunable Microwave Source; Design and Evaluation of a Josephson Array Oscillator; Obtaining High-Accuracy Measurements from Low-Accuracy Measurements; Superconducting Microwave Transmission Lines; High Performance, Superconducting Analog-to-Digital Converter; Edge Sharpening with Josephson Junction; Design Evaluation of a Subranging Superconducting Analog-to-Digital Converter; Feasibility Study of a Superconducting Sigma-Delta Analog-to- Digital Converter, and VHDL Simulation Study of Superconducting Sigma Delta Modulators.

•Sep 1, 1991•0 citations
The main topic of this thesis is the evaluation of performance of super-conducting rst- and second-order low-pass sigma-delta modulators. Superconducting electronics comprise characteristics such as very high switching speed, natural quantization, high sensitivity and low noise, proper-ties that are all essential for modulators used in high performance analog-to-digital converters (ADC). Sigma-delta modulators trade speed for improved resolution using feedback mechanisms making superconducting electronics an interesting alternative technology for the implementation. With linear models and device-level simulations the performance of these modulators have been evaluated. The linear model of the rst-order sigma-delta modulator shows that the performance, for a given oversampling ratio, only depends on the cut-o frequency of the RL-lter used. This is veried by device-level simulations and the results from the two methods are in good agreement. Device-level simulations of the second-order sigma-delta modu-
Superconducting digital circuits are capable of producing high dynamic range analog-to-digital converters (ADCs). We present sigma-delta architectures using large (>100) oversampling ratios to give signal-to-noise ratios of greater than 100 dB in simulation. Three distinct designs, using two distinct mechanisms for feedback, are presented. All of the designs use only shunted junctions, and are therefore compatible with HTS SNS junctions. Simulations are presented for a modulator which creates feedback pulses by SQUID lobe-crossings, a modulator which uses the transresistance of a SQUID for feedback, and a modulator which uses threshold crossings in both the first and second loops for feedback.
We have been developing a superconducting second-order sigma-delta analog-to-digital converter with a large bandwidth and a large dynamic range for software radio applications. In a superconducting second-order sigma-delta modulator utilizing a passive integrator and single-flux-quantum (SFQ) feedback, gain to compensate the large attenuation in the passive integrator of the modulator is required to obtain a large dynamic range. In this paper, a second-order modulator utilizing multi-flux-quantum (MFQ) generators creating the needed gain is reported and the design and experimental test results of the elementary circuits including a comparator, a first-order modulator, and the MFQ generator are described. The digital outputs of the comparator and the first-order modulator were experimentally evaluated, where the input dependence of the comparator switching probability and the noise-shaping properties of the modulator were clearly observed. The low speed operation of the MFQ generator creating three SFQ pulses was experimentally confirmed. The other circuits were also tested at low frequencies.
High performance oversampling delta-sigma data converters require high clock rates and accurate feedback of the digital output to the analog regime. Superconductor modulators offer the unique advantages of clock rates in the tens-of-gigahertz, comparator switching energy below attoJoules, and quantum-accurate digital-to-analog feedback. We have designed a two-loop baseband modulator whose noise transfer function was calculated using a simple, linear circuit model. The circuit was fabricated in a commercial superconductor IC process with 4.5 kA-per-square cm Josephson junctions and 1.5 micron minimum feature size. The circuit was tested at a derated sample rate of 5 GHz. Measured signal-to-noise dynamic range was 81 dB over a 10 MHz band. Third-order intercept was measured to be +24 dBsat in two-tone test. The measured noise transfer function was in excellent agreement with our linear model. The linear model indicates that with appropriate parameter values, this family of modulators extrapolates to significantly higher performance.
A wide variety of applications, ranging from radio-frequency (RF) receivers for broadband communications and signal detection, on earth and in space, would benefit from high-performance superconductor analog-to-digital converters (ADCs), based on magnetic flux quantization and fast switching Josephson junctions. Superconductor ADCs are capable of very high sample rates (100 GHz or more), very high linearity, and high sensitivity. Nyquist-rate ADCs use the high sample rate to digitize a wide instantaneous bandwidth (tens of GHz) and are useful for wideband spectrum monitoring as well as high-end scientific instrumentation. Delta and delta-sigma oversampling ADCs use the high linearity to achieve programmable trade-off between dynamic range and instantaneous bandwidth. These lowpass and bandpass ADCs have been used for direct digitization of narrower (tens to hundreds of MHz) RF bands in the 1-20 GHz range for a variety of communications, intelligence, electronic warfare, and radar applications. Another application area of these cryogenic ADCs is for outputs of cryogenic sensor arrays and terahertz mixers. Recent advances in various classes of ADCs for different applications are described.
Ultrafast switching speed, low power, natural quantization of magnetic flux, quantum accuracy, and low noise of cryogenic superconductor circuits enable fast and accurate data conversion between the analog and digital domains. Based on rapid single-flux quantum (RSFQ) logic, these integrated circuits are capable of achieving performance levels unattainable by any other technology. Two major classes of superconductor analog-to-digital converters (ADCs) are being developed - Nyquist sampling and oversampling converters. Complete systems with digital sampling at rates of /spl sim/20 GHz and above have been demonstrated using low-temperature superconductor device technology. Some ADC components have also been implemented using high-temperature superconductors. Superconductor ADCs have unique applications in true digital-RF communications, broadband instrumentation, and digital sensor readout. Their designs, test results, and future development trends are reviewed.
Contents: Superconducting Analog-to-Digital Converter Work at MITRE; Development of a Rapidly Tunable Microwave Source; Design and Evaluation of a Josephson Array Oscillator; Obtaining High-Accuracy Measurements from Low-Accuracy Measurements; Superconducting Microwave Transmission Lines; High Performance, Superconducting Analog-to-Digital Converter; Edge Sharpening with Josephson Junction; Design Evaluation of a Subranging Superconducting Analog-to-Digital Converter; Feasibility Study of a Superconducting Sigma-Delta Analog-to- Digital Converter, and VHDL Simulation Study of Superconducting Sigma Delta Modulators.