HIGH SPEED DIGITAL DATA TRANSMISSION

IT IS ANTICIPATED THAT LASER TECHNOLOGY WILL BE UTILIZED FORHIGH SPEED DATA TRANSMISSION BETWEEN NEXT GENERATION SPACECRAFT. NEWER CIRCUIT TECHNOLOGY AND DATA RECOVERY TECHNIQUES WILL BE REQUIRED TO SUPPORT THE HIGHER BIT RATES. THIS PROPOSAL OUTLINES AN APPROACH TO IMPLEMENT THE CLOCK AND DATA RECOVERY CIRCUITRY WHERE THE REFERENCE CLOCK IS OPERATING AT THE DATA RATE RATHER THAN A MULTIPLE OF THE DATA RATE. THE PROPOSED CIRCUITRY WOULD BE IMPLEMENTED WITHGALLIUM ARSENIDE TECHNOLOGY AND OFFER AN UPPER OPERATIONAL DATA RATE PERFORMANCE IN THE 1-2 GBIT/SEC RANGE. DATA CODING TECHNIQUES WITH RESPECT TO SYSTEM PERFORMANCE (I.E. TRANSMISSION POWER, REFERENCE CLOCK RATE WITH RESPECT TO DATA RATE, TOLERANCE TO JITTER, ERROR DETECTION AND CORRECTION TECHNIQUES, WORST CASE SYNCHRONIZATION TIME, IMPLEMENTATION COMPLEXITY, ETC.) WILL BE A PART OF THE DESIGN CRITERIA. MANCHESTER AND QPPM CODING OF THE DATA WILL BE EVALUATED IN THE DESIGN. GAAS IS THE DEVICE TECHNOLOGY RECOMMENDED BECAUSE OF ITS SUPERIOR SPEED-POWER PRODUCT, TOLERANCE TO RADIATION EFFECTS, AND HIGH SPEED OPERATION.