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BELL SYSTEM TECHNICAL JOURNAL 



The first tube designed for this service was the 2K23. It was based on 

 the design employed in the 2K29 and operated with a drift time of If cycles 

 in the repeller space. A severe limitation on the performance was set by 

 by the requirement that a single oscillator should cover the frequency range 

 from 4275 to 4875 Mc/s. It is shown in Section X that in an oscillator tuned 

 by changing the capacitance of the gap the efficiency will vary considerably 



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FREQUENCY IN MEGACYCLES PER SECOND 



Fig. 99. — Variation of the peak power output vs frequency for the 2K23 reflex oscillator. 

 This tube was designed for pulse operation withja duty factor of 10 in a repeller mode 

 having 3.5 t radians drift. 



I'ig. 100. — Modulator circuit for use in connection with reflex oscillators showing 

 means for applying pulse voltage to the repeller to reduce frequency modulation during 

 pulsing. 



over such a tuning range. In the case of the 2K23 the variation of the peak 

 pow-er output with frequency is shown in Fig. 99. The duty factor at which 

 the tube was used (the ratio of the time between pulses to the pulse length) 

 was 10. In the AX TRC-6 application the tube was operated on a fixed 

 current basis; i.e., the pulse amplitude was adjusted to a value such that 

 the average current drawn was 15 ma. The schematic of the circuit em- 

 ployed in pulsing oscillators in this way is shown in Fig. 100. The resonator 



