Repeater Design for the North Atlantic Link 



T. F. GLEICHMANN,* A. H. LINCE,* M. C. WOOLEY* and 



F. J. BRAGA* 



(Manuscript received October 8, 1956) 



Some of the considerations governing the electrical and mechanical de- 

 sign of flexible repeaters and their component apparatus are discussed in 

 this paper. The discussion includes description of the feedback amplifier 

 and the sea-pressure resisting container that surrounds it. Examples are 

 given of some of the extraordinary measures taken to ensure continuous per- 

 formance in service. 



INTRODUCTION 



Repeaters for use in the transatlantic submarine telephone cable sys- 

 tem had to be designed to resist the stresses of laying, and to withstand 

 the great pressures of water encountered in the North Atlantic route. 

 In anticipation of the need for such a long telephone system in deep 

 water, development work was started over 20 years ago on the design 

 of a flexible repeater that could be incorporated in the cable and be 

 handled as cable by conventional cable ship techniques. Successful com- 

 pletion, in 1950, of the design and construction of the 24-channel Key 

 West, Florida-Havana, Cuba system,^ led to the adoption of similar 

 repeaters designed for 36 channels for the North Atlantic link discussed 

 in companion papers.^- ^ 



Repeater transmission characteristics determine, to a large extent, 

 the degree to which system objectives can be met. In this repeater, sig- 

 nificant characteristics are: 



(a) Noise and Modidation. These were established by the circuit con- 

 figuration and by the use of the conservative electron tube^ developed 

 for the Key West-Havana project. 



(b) Initial Misalignment, or mismatch of repeater gain and cable loss 

 throughout the transmitted band of frequencies. A match within 0.05 

 db was the objective. This affected both the design and the precision 

 required in manufacture. 



* Bell Telephone Laboratories. 



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