A COUPLED RESONATOR REFLEX KLYSTRON 



759 



perimental curves shown are as follows: 



6BL6 repeller mode = 3 -{- ^^ 



Resonator voltage, Vq 



Cathode current, h 



Midmode repeller voltage, Vr 



Midmode frequency, /o 



Secondary Q, Qs 



^4 cycles 

 = 325 volts 

 = 28 ma 

 = -96 volts 

 = 3800 mc 



= 3^ prunary Q = 65, obtained by mi- 

 crometer reading of 0.234 (see Fig. 



The parameter, (Qkf, was varied by adjusting the iris width, and hence 

 k, according to Table III. 



A few words, next, about the method by which the theoretical curves 

 of Fig. 20 were derived. Input admittance plots for two coupled resona- 

 tors having Qs = J^Q were given earlier in this report (see Fig. 11). 



Table III 



These included graphs for the values of (Qkf listed in Table III and 

 thus of direct use in a graphical admittance plane analysis such as 

 described in Section 3.2. To establish correlation, however, between 

 theory and experiment, it was necessary to determine the location of the 

 load lines in relation to the small-signal electronic admittance plot for 

 the 3 + % repeller mode. This was performed graphically by trial and 

 error as follows : a number of electronic admittance loci were drawn and 

 their interactions with the load line for (Qkf = 2.4 studied. In particu- 

 lar, the ratio of minimum to maximum power was calculated for each 

 trial until one was found agreeing well with the experimental value of 

 0.845 (see Fig. 20d). This latter trial, then, was taken as representing 

 the proper relation between electronic and circuit admittance. Mode 

 plots for other values of (Qkf were determined without further reference 

 to the experimental results and allowed to fall where they may. 



In comparing the theoretical and experimental curves, then, the fol- 

 lowing points should be kept in mind: the frequency scales of the the- 

 oretical curves are normally expressed in terms of Qd. This was converted 



