Repeater Design for the North Atlantic Link

Repeaters for use in the transatlantic submarine telephone cable system had to be designed to resist the stresses of laying, and to withstand the great pressures of water encountered in the N o r t h 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 completion, in 1950, of the design and construction of the 24-channel Key West, Florida-Havana, Cuba system, 3 led to the adoption of similar repeaters designed for 3(> channels for the N o r t h Atlantic link discussed in companion papers. 1 , 2 Repeater transmission characteristics determine, to a large extent, the degree to which system objectives can be met. In this repeater, significant characteristics are: (a) Noise and Modulation. These were established by the circuit configuration and by the use of the conservative electron tube 8 developed for the Key W e s t - H a v a n a project. (b) Initial Misalignment, or mismatch of repeater gain and cable loss throughout the transmitted band of frequencies. A m a t c h within 0.05 db was the objective. This affected both the design and the precision required in manufacture. * Bell Telephone Laboratories. 69