838 THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1956 



33 K 



OUT 



soon 



I+15V 



Fig. 19 — Circuit of a 60 to 80-mc band pass amplifier stage. 



32 



in 



0^ (1) 

 lU CO 



28 



< - 



cr 



Q 24 



Z 



< 20 



O 



16 



54 58 62 66 70 74 78 82 



FREQUENCY IN MEGACYCLES PER SECOND 



86 



Fig. 20 — Gain of a 3-stage band pass amplifier working between 75-ohm im- 

 pedances. Each stage uses the circuit shown on Fig. 19. 



(0 



cc 

 o 



\- 



Z 3 

 < 



cr 



I- 



u. 



^2 



a. 



UJ 



CD 

 Z 1 



4 — 





5 6 7 8 9 10 n 



GAIN IN DECIBELS 



12 



Fig. 21 — Variation of gain for a grouj) of transistors used in the circuit of 

 Fig. 19. 



