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BELL SYSTEM TECHNICAL JOURNAL 



Referring to Fig. 26 let A represent the positive halves of the open 

 circuit voltage across the secondary of the interstage transformer due 

 to the steadily impressed carrier; and B represent the instantaneous 



E SIN u;(t + ti) 



TIME (t) 



Fig. 26 — Theory of level compensator. A. Carrier voltage. 

 B. Condenser charge. 



charge on the condenser. Reckoning time from the instant a when the 

 grid goes positive, we have: 



e = E sin w{t + ^i), 



(2) 



where co/27r is the carrier frequency. 



Consider the instant at which / = — /i: e is increasing through its 

 zero value, the switch representing the grid-filament space (Fig. 255) 

 is open and the condenser is discharging through Re. This state of 

 affairs continues until e reaches a value which nullifies the condenser 

 voltage plus the steady grid bias so that the voltage across the switch 



