1316 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1954 



^ GUARD 

 VOLTAGES 



Fig. 3 — Limiter characteristics. 



o 



1000 1500 2000 2500 



FREQUENCY IN CYCLES PER SECOND 



Fig. 4 — Signal-guard characteristics used in signal imitation tests. 



Table III 



Receiver sensitivity (0 level) 



Receiver signal bandwidth (3 db points), at just operate level 



'■" approx 



Guard to signal ratio 



Start of limiting above just operate, approx 



Minimum duration signal for operate 



