672 



BELL SYSTEM TECHNICAL JOURNAL 



Higher Frequency Repeaters 

 Most of what has been said above appUes particularly to repeaters 

 transmitting frequencies up to about 1000 kilocycles. However, 

 study has been given also to repeaters, both of the feedback and the 

 non-feedback type, for transmitting higher frequencies. Experimental 

 repeaters covering the range from 500 to 5000 kilocycles have been built 

 and tested. These were capable of handling simultaneously the full 

 complement of over 1000 channels which such a broad band will 

 permit. The frequency characteristic of one of these repeaters, and the 

 measured attenuation of a section of line of the type tested at Phoenix- 

 ville are shown in Fig. 14. 



M45 



Z 35 



30 



0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 



FREQUENCY IN MEGACYCLES PER SECOND 



Fig. 14 — Frequency characteristic of coaxial line and 5000-kilocycle repeater. 



Terminal Arrangements 



In order to utilize a broad band effectively for telephone purposes, 

 the speech channels must be placed as close together in frequency as 

 practicable. The factors which limit this spacing are: (1) The width of 



