SF System: An Overview: Requirements and Performance

01 May 1970

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Aii Overview: Requirements and Performance By CLEO D. ANDERSON and R O B E R T L. EASTON (Manuscript received February 19, 1970) This article describes the considerations which led to choice of the SF System design objectives and gives an overview of the system. It further discusses various system parameters and the techniques of laying and adjusting the system for optimum signal-to-noise performance. Finally, the article shows performance results of the recently completed TAT-5 System which extends from Rhode Island to Spain. These results show good agreement with calculated system performance. I. INTRODUCTION* At the time of the first transatlantic SD System installation in 1963, it was already clear that a new system with considerably more capacity would be required to meet the traffic demands of the early 1970s. Economic studies indicated that the large potential demand expected by that time would justify the greatest bandwidth achievable from available technology and consistent with high reliability. Both the SB and SD Systems used vacuum tubes as the active device. As a result, the maximum terminal voltage which could be applied to power the systems without unduly affecting the reliability of the high voltage undersea components was a determining factor on the maximum feasible number of repeaters. This maximum limit, in turn, limited the bandwidth of these systems. The availability of transistors with their lower power requirements removed powering voltage as an important constraint.