A CARRIER TELEPHONE SYSTEM FOR TOLL CABLES 



93 



The correction introduced by the line equalizers is subject to errors 

 which, although small at each repeater point, become important for 

 a moderate length of system. Supplementary equalizers have been 

 designed to correct for these. Two types of deviation are considered, 



75 



65 



m 60 

 m 



o 



UJ 



Q 55 



50 



45 



40 



35 



15 20 25 30 35 40 45 50 



FREQUENCY IN KILOCYCLES PER SECOND 



Fig. 10 — Amplifier gain characteristics. 



55 



70 



that of the cable and that of the amplifier. As the characteristics of 

 cables manufactured at different times show slight departures from 

 one another, two shapes are required to correct their deviations. 

 There is one correction for concave deviations and another for convex. 



2 



10 15 20 25 30 35 40 45 50 



FREQUENCY IN KILOCYCLES PER SECOND 



Fig. 11 — Characteristics of cable deviation equalizers. 



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The amplifier requires but one type of correction. The characteristics 

 of these equalizers are shown in Figs. 11 and 12. The equalizers for 

 amplifier deviations are used about every 10th repeater and those for 

 the cable deviations, at distances of 300 to 400 miles. At normal 

 temperature (55° F.), the correction applied by these networks will. 



