504 



BELL SYSTEM TECHNICAL JOURNAL 



1. Telephone Cable. — Two of the cases where phase distortion in 

 telephone cable has been considered objectionable will be discussed: 

 (1) In the newly developed high quality cable circuit for transmitting 

 programs to and between broadcasting stations '^ which circuit is 



1,000 



2,000 3,000 4,000 5,000 6,000 7,000 



FREQUENCY IN CYCLES PER SECOND 



8,000 9P00 



Fig. 1 1 — Insertion phase characteristic of a 50 mile length of cable for program trans- 

 mission. Also, phase characteristic of a phase corrector for this cable and for the sum 

 of the two 



designed to transmit with negligible amplitude and phase distortion 

 all frequencies between 50 and 8000 cycles and (2) a proposed cable 



i"* Long Distance Cable Circuit for Program Transmission, A. B. Clark and C. W. 

 Green, to be presented at Summer Convention A. L E. E., Toronto, June, 1930. 

 This cable consists of No. 16 gauge copper wire witli 22 millihenry loading coils 

 spaced e\-ery 3000 feet. 



