DESIGN STUDY OF SUPERCONDUCTING OVERSAMPLING FLUX-COUNTING A/D CONVERTERS USING RAPID SINGLE FLUX QUANTUM (RSFQ) LOGIC

HYPRES PROPOSES A PROGRAM TO RESEARCH, DEVELOP, AND DEMONSTRATE FEASIBILITY OF A NEW FAMILY OF HIGH-PERFORMANCE SUPERCONDUCTING A/D CONVERTERS USING THE PRINCIPLES OF COUNTING SINGLE MAGNETIC FLUX QUANTA AND OVERSAMPLING; IT IS CAPABLE OF BOTH WIDE-BANDWIDTH AND HIGH ACCURACY OPERATION BY MAINTAINING UNIQUE BANDWIDTH-ACCURACY TRADEOFF RATIO OF 1.5 EFFECTIVE BITS (INSTEAD OF USUAL 1 BIT) PER FACTOR-OF-2 BANDWIDTH REDUCTION WHILE STARTING AS HIGH AS 1 BIT AT 20-50 GHZ BANDWIDTH (DEPENDING ON TECHNOLOGY LEVEL). THE PROPOSED ADC FAMILY IS EMPLOYING RECENTLY DEVELOPED RAPID SINGLE FLUX QUANTUM (RSFQ) LOGIC/ MEMORY ELEMENTS CAPABLE OF CLOCK FREQUENCIES IN EXCESS OF 100 GHZ. IN PHASE I WE INTEND TO COMPLETE THEORETICAL STUDY OF THIS ADC FAMILY AND TO DESIGN, FABRICATE AND DEMONSTRATE ITS KEY COMPONENTS OPERATING AT MULTI-GHZ CLOCK FREQUENCIES. IN PHASE II WE PLAN TO CONTINUE THIS WORK WITH THE AIM OF OBTAINING A WORKING PROTOTYPE OF OVERSAMPLING FLUX-COUNTING ADC DEMONSTRATING THE IMPROVED ACCURACY/BANDWIDTH TRADE-OFF RATIO MENTIONED ABOVE. THE PRINCIPAL BENEFITS ARE EXPECTED TO BE IN HIGH-SPEED REAL-TIME SIGNAL PROCESSING WHERE WIDEBANDWIDTH AND/OR HIGH ACCURACY DIGITIZATION OF TRANSIENTS IS IMPERATIVE, SUCH AS RADAR, DIGITAL TV, ENCRYPTED COMMUNICATIONS, HIGH-SPEED ELECTRONICS INSTRUMENTATION, ELECTRONIC WARFARE SYSTEMS, ETC. COMBINATION OF THE FLUX COUNTING APPROACH WITH THE OVERSAMPLING TECHNIQUE WILL DRASTICALLY IMPROVE BOTH STATIC AND DYNAMIC ACCURACY OF A/D CONVERSION, LEADING TO CONVERTORS WITH PERFORMANCE TO 16 EFFECTIVE BITS AT BANDWIDTHS OF 20-50 MHZ.