380 



BELL SYSTEM TECHNICAL JOURNAL 



(75 ohms), which is constant over the frequency range of interest. Con- 

 currently it is relatively simple to present to the emitter a high impedance, 



00 — I MIX 



25-40 MC 



HIGH R 



DETECTOR 



^O 



SCOPE 



LOW R 



Fig. 12 — Sweeper for measuring frequency response. 



uj -2 



Z -4 

 < 



z 



O -6 



3 4 5 6789 10 



FREQUENCY IN CYCLES PER SECOND 



Fig. 13 — Alpha versus frequenc\-. 



20 

 X10« 



that is, to drive it witli a constant current generator. Under these conditions 

 the insertion power gain of the transistor is appro.ximatcly a-, where the 

 current amplification factor a is the ratio of increment in collector current to 



