1320 THE BELL SYSTEM TECHNICAL JOURNAL, NOVEMBER 1956 



35.0 



Z 



g 

 m 

 a 12.50 



UJ 



> 



2 



q 11.25 



2 



Q. 10.00 

 I 



o 



5 

 < 



5.00"- 



32.5 

 30.0 



I 8.75 - CD 27.5 



O 



7.50 h '=' 25.0 



Z 



6.25 I- Z 22.5 



< 



20.0 

 17.5 



15.0 

 2200 



2300 2400 2500 2600 



HELIX VOLTAGE IN VOLTS 



2700 



100 9 

 in 



LU 



75 Q: 

 Q. 



50 8 



I- 



25 5 

 O 



o5 



2800 II- 



Fig. 25 — Gain, compression and amplitude to phase conversion as a function 

 of heli.x voltage with the output power maintained constant at a level of five 

 watts (a) and ten watts (b). 



there is expansion for some values of power input. Figs. 23 (e) and 23(f) 

 give the AM-to-PM conversion, as functions of input and output power 

 respectively. These data indicate that the conversion is very much less 

 if the tube is operated at lower helix voltages. For example, the con- 

 version at the saturation level of the 2, 700- volt curve is about 2^ times 

 that for the 2, 400- volt curve. 



A final method of plotting gain, compression, and AM-to-PM con- 

 version data is shown in Fig. 25. The abcissa here is the helix voltage. 



