THE N-1 CARRIER SYSTEM 



27 



current held despite changes in supply voltage, cable conductor resistance 

 and tube space current, that the heater voltage and current can be adjusted 



■14 -12 



■10 -8 -6 



-4-2 2 4 6 



REPEATER INPUT IN DECIBELS 



10 



12 



16 



Fig. 13 — Regulation characteristics of ,high-low and low-high repeaters. 



to values below those used in telephone offices. As a result an appreciable 

 increase in tube life is obtained compared to that obtained in offices under 

 ordinarily regulated battery conditions. 



