ADVANCES IN CARRIER TELEGRAPH TRANSMISSION 



171 



-12 -10 -8 -6 -4 ■ -2 2 4 6 8 10 12 14 



VARIATIONS IN DETECTOR-INPUT LEVEL IN DECIBELS 



Fig. 4 — Effect of level compensator. Signal bias vs. variations in detector input 

 level. Signaling speed 23 dots per second. 



range when the level compensator is used are of the order shown in 

 Fig. 5, indicating satisfactory operation over extensive changes in 

 circuit loss. It will be seen that in the absence of a level compensator 

 a single-section telegraph circuit operating at a speed of 23 d.p.s. (46 



-14 -12 -10 -8-6-4-2 2 4 6 8 10 12 



VARIATIONS IN DETECTOR-INPUT LEVEL IN DECIBELS 



Fig. 5 — Teletypewriter orientation-range vs. variations in detector input-level. 



