A 10 GHz oversampling delta modulating analogue-to-digital converter implemented with hybrid superconducting digital logic

Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: Rapid Single Flux Quantum (RSFQ) logic cells are discussed, and new cells developed. The expected yield of every cell is computed through a Monte Carlo analysis, and where necessary these cells are optimized for use in a complex system. A mathematical study of the Josephson junction and SQUIDs (Superconducting Quantum Interference devices) as switching elements precede a discussion on the operation of RSFQ and COSL (Complementary Output Switching Logic.) These logic families are implemented in low temperature niobium technology, and require liquid helium cooling. A 10 GHz oversampling delta modulating analogue-to-digital converter is then designed and constructed using RSFQ and COSL building blocks in a hybrid configuration. The design emphasis is on devising ways to test the operation of RSFQ with limited equipment. Yield analysis procedures on the complex system are discussed, followed by a detailed discussion on the circuit layout and layout problems. Software routines are developed to calculate the required dimensions of layout structures.AFRIKAANSE OPSOMMING: Rapid Single Flux Quantum (RSFQ) logiese selle word bespreek, en enkele nuwe selle word ontwikkel. Die verwagte opbrengs, of kans dat 'n sel sal werk, word bereken deur 'n Monte Carlo analise. Waar nodig word selle met behulp van die analise verbeter vir gebruik in 'n komplekse stelsel. 'n Wiskundige studie van die Josephson-vlak en SQUIDs (Superconducting Quantum Interference devices) word gevolg deur 'n bespreking oor die werking van RSFQ en COSL (Complementary Output Switching Logic.) Hierdie logiese families word geïmplementeer in laetemperatuur niobiumtegnologie, en vereis vloeibare helium-verkoeling. 'n Deltamodulerende analoog-na-digitale omsetter met 'n intree-monstertempo van 10 GHz word ontwerp en vervaardig met 'n hibriede samestelling van RSFQ en COSL boublokke. Die ontwerp fokus op maniere om die werking van RSFQ teen 10 GHz te kan toets met die beperkte toerusting wat beskikbaar is. Opbrengsanalise op die komplekse stelsel word bespreek, gevolg deur 'n volledige bespreking van die stroombaanuitlegprosedure en uitlegprobleme. Roetines word in sagteware ontwikkel om die nodige dimensies van uitlegstrukture te bereken

A tool kit for the design of superconducting programmable gate arrays

Thesis (PhD)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: The development of a tool kit for the design of superconducting programmable gate arrays (SPGAs) is discussed. A circuit optimizer using genetic algorithms is developed and evaluated. Techniques and a program are also developed for the generation of segmentized 3D models with which to calculate inductance in circuit structures through FastHenry. The ability to add random variations to the dimensions of the models is included. These tools are then used to design novel latching elements that allow the construction of reprogrammable Rapid Single Flux Quantum (RSFQ) circuits. A circular process is used, whereby layouts are converted back to circuit diagrams through element extraction, and reoptimized if necessary. Two programmable frequency dividers are then designed; one for testing the routing and switch structures and programming architecture of an SPGA, and another compact one for testing the latching elements and off-chip interface. The dissertation concludes with an overview of the circuits necessary for the implementation of a fully functional SPGA.AFRIKAANSE OPSOMMING: Die ontwikkeling van ’n gereedskapstel vir die ontwerp van supergeleier FPGA’s (SPGA’s) word bespreek. Eerstens word ’n stroombaanoptimeerder, wat met genetiese algoritmes funksioneer, ontwikkel en geëvalueer. Daarna word tegnieke en ’n program ontwikkel om driedimensionele segmentmodelle te genereer waaruit FastHenry die induktansie van stroombaanstrukture kan bepaal. Die vermoë om toevalsveranderinge by die dimensies van die modelle te voeg, is ook ingesluit. Hierdie gereedskap word dan gebruik om nuwe grendelelemente te ontwerp waarmee herprogrammeerbare Rapid Single Flux Quantum (RSFQ) stroombane gebou kan word. ’n Sirkulêre proses word gevolg, waarvolgens uitlegte na stroombaandiagramme teruggeskakel kan word (deur elementonttrekkings) en, indien nodig, heroptimeer kan word. Twee programmeerbare frekwensiedelers word daarna ontwerp; een om die pulsvervoer- en skakelstrukture, asook programmeringsargitektuur van ’n SPGA te toets, en ’n ander, kompakter een om die grendelelemente en warmlogika koppelvlakke mee te toets. Die proefskrif sluit af met ’n oorsig oor die stroombane benodig vir die implementering van ’n volledig funksionele SPGA

Influence of magnetic field orientation ad magnitude on the behaviour of Delay-Flip-Flop RSFQ cells

International audienc

Investigation of three-dimensional digital circuits with nanometer Josephson junctions made by Focused Ion Beam

session poster (4EP1-18)International audienc

Analysis of different magnetic field noise environments for preparing a long-base highly-sensitive magnetic interferometer

session P36International audienc

Analysis of different magnetic field noise environments for preparing a long-base highly-sensitive magnetic interferometer

session P36International audienc

SQUID magnetometers: a tool for ultrasensitive measurements embedded in a controlled network environment

National audienc