516 



BELL SYSTEM TECHNICAL JOURNAL 



The diagrams so far o])tained have been based on the assumption that A0 

 has been held constant. To obtain such a diagram experimentally would be 

 extremely difficult. It would require that, as the frequency changed through 

 load puUing, and hence the total transit angle d = IttJt changed, an adjust- 

 ment of the repeller voltage be made to correct the change. In actual 

 practice, Rieke diagrams for a reflex oscillator are usually made holding the 



LOAD POWER AG 



LOAD POWER Ae= 



Fig. 33. — A transformation of the Rieke diagram of Fig. 32 showing the effect of shifting 

 the drift angle away from the optimum l)v 45°. 



transit time r constant or in other words, with fixed operating voltages. 

 What this does to the basic diagram of Fig. 32 is not difficult to discover, 

 I)rovided that bd is sufficiently small so that we may ignore the variations 

 of the Bessels functions with bd. We will tirst investigate the effect of fixed 

 repeller voltage on the constant frequency contours. To do this we will 

 rewrite (*X11), rei)lacing A0 by A^ + bd and expand. 



Aco 



ACOT = COoT 



Wo 



(9.15) 



