REFLEX OSCILLATORS 



503 



Inasmuch as multiple transits appear to be the most common cause for 

 hysteresis in reflex oscillator design, it seems worthwhile to obtain a more 

 detailed understanding of the mechanism in this case. Other possible 



z9 



100 

 90 

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 50 

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to 





 50 



40 



30 



20 



10 







-10 



-20 



-30 



-40 



1 20 

 NEGATIVE 



130 140 



REPELLER VOLTAGE 



Fig. 27. — Amplitude, frequency and transit phase variation with the repeiler voltage 

 obtained experimentally for a reflex oscillator exhibiting electronic hysteresis. The 

 arrows indicate the direction of variation of the repeiler voltage. 



mechanisms such as velocity sorting on the repeiler will give rise to similar 

 effects and can be understood from what follows. 



In the first order theory, the electrons which have retraversed the gap 

 are conveniently assumed to vanish. Actually, of course, the returning 

 stream is remodulated and enters the cathode space. Unfortunately, the 



