506 



BELL SYSTEM TECHNICAL JOURNAL 



dBjdoi for the cable, the phase corrector, and the two combined. A 

 50 mile length of corrected cable gives a delay of .00375 seconds. A 

 3000 mile length " of this cable such as would extend from coast to 

 coast would give a delay of .225 seconds, with a difference between the 



36,000 



32,000 



28,000 



24,000 



(0 



lU 

 Ul 



a. 



o 



Q 20,000 



I 



W 16,000 



tu 



< 

 I 

 Q. 



12,000 



8;000 



4,000 



400 



800 1,200 1,600 2,000 2,400 



FREQUENCY IN CYCLES PER SECOND 



2,800 



3,200 



Hg. 14 — Insertion phase characteristics of a 500 mile length of cable for telephone 



message service. 



minimum and maximum value of .006 seconds in the corrected range. 

 Without correction this difference would have been .055 seconds. 



Figs. 14, 15 and 16 correspond respectively to the previous three but 

 are for a 500 mile length of the cable for regular telephone message 

 service. The total delay for 500 mile length of this cable after correc- 



'' In designing apparatus going in long distance circuits in general the parts are so 

 designed that if a circuit 3 or 4 thousand miles long is used the total accumulated 

 distortion due to either amplitude or phase will be within tolerable limits. 



