ULTRA-HIGH-FREQUENCY POWER AMPLIFIER 



21 



portance at ultra-high frequencies of circuit design in the over-all 

 performance of an amplifier or modulator, such tests cannot be con- 

 sidered as a definite measure of the capabilities and limitations of the 

 tube but they indicate what has already been accomplished. 



When operating as a class A amplifier at 150 megacycles an output 

 of one watt is obtained with the distortion forty decibels below the fun- 



28 



2 



O 24 



20 



16 



12 



60 70 80 90 



TOTAL SPACE CURRENT IN MILLIAMPERES 



Fig. 9 — The variation in input resistance with operating conditions 

 at 150 megacycles. 



100 



damental. Under these conditions the stage gain is twenty decibels. 

 Outputs of ten watts with a plate efficiency of sixty to seventy per cent 

 and a gain of ten decibels are secured with class B operation. Ex- 

 perimental results confirming these statements together with a dis- 

 cussion of the principles of circuit design and the technique of measure- 

 ments are given in the accompanying paper by N. E. Sowers. 



