604 



BELL SYSTEM TECHNICAL JOURNAL 



REACTANCE 

 TUBE 



+ B 



Vk L 



(MEGACYCLES) 



WHERE 



K = DIELECTRIC CONSTANT. 

 L= LENGTH OF LINE IN 

 METERS. 



Fig. 6 — Transmission line reactance tube modulated oscillator. 

 36 



34 

 33 



u 32 



5 



29 

 28 



' I ^! !i 



2.0 d 

 > 



K 



1.0 o 



-15 -13.5 -12.0 -10.5 -90 -7.5 



3.0 -4.5 -3.0 



REACTANCE TUBE GRID VOLTS 



Fig. 7 — Performance curves of typical LC reactance tube modulated phase shift 

 oscillator. 



simplified form is shown in Fig. 1. The input and output of a vacuum 

 tube amplifier are connected together by a tuned circuit and feedback 

 network which introduces 180° phase shift at the undeviated frequency Fq . 



