150 



BELL SYSTEM TECHNICAL JOURNAL 



oscillating vacuum tube. The axes were obtained by grounding one 

 or the other deflector element. 



The measurement of modulation in a radio transmitting set has 



Fig. 5 



been reduced to a fairly simple process by means of the cathode ray 

 tube. The low frequency modulating voltage, controlled by the 



'■* 



1 ^ 



Ep 



'/f 



i 



Fig. 6 



