REFLEX OSCILLATORS 



499 



This admittance will be a pure conductance if = 0o = (« + f ) 27r. As 

 we have seen, in an oscillator designed specifically for electronic tuning, n 

 usually has a value of 3 or greater and the variations M from 6 arising from 



BUNCHING PARAMETER, X »• 



Fig. 24. — A curve of power output vs parameter X resulting from the conductance 

 curves shown in Fig. 23 and illustrating hysteresis. 



repeller voltage variation are sufficiently small so that the efifect of M in 

 varying .Y may be neglected. In this case we may write 



Ge = -Je L„ COS ^^ 



cv 



ye = 



c = 



2Fo 

 M 



(8.8) 



The parameter which we vary in obtaining the repeller characteristic of 

 the tube is Ad. The variation of this parameter is produced by shifting the 

 repeller voltage Vr from the value Fro corresponding to the transit angle 



do . Since as is shown, Fig. 25a, ^ decreases monotonically as V 



increases, no explanation of hysteresis is to be found in this expression. 

 Fig. 25b shows the smooth symmetrical variation of output with repeller 

 voltage about the value for which A^ = which is to be expected. 



