The picturephone® system: Mastergroup digital transmission on modern coaxial systems

We describe in this paper a system currently under development that will adapt the L-4, and later the L-5, coaxial system for digital transmission in mastergroup bands. The terminal equipment will combine two 6.312 Mb/s digital signals and, hence, two Picturephone® signals in digital form for transmission on the coaxial systems along with analog message channels in other mastergroups. The overall system includes regenerative repeaters at intervals of not more than 300 miles to realize the error rate objective of 2.6 × 10⁻⁷, or better, for distances up to 4000 miles.