TUBE FOR PULSE CODE MODULATION 57 



Coding tubes have operated satisfactorily for long periods of time in the 

 experimental multi-channel pulse code system and have required minor 

 adjustments of potentials no more than once a day. The tube operates in 

 this equipment with a code sweep time of 10 microseconds. 



Acknowledgment 



The writer wishes to acknowledge the original suggestions of Dr. F. B. 

 Llewellyn and Mr. G. Hecht and the help of his colleagues. The contribu- 

 tions and wholehearted cooperation of Messrs. C. B. Feldman, L. A. 

 Meacham and their associates who concurrently developed the pulse code 

 system and circuits associated with the coding tube, have been invaluable. 

 Mr. A. Salecker deserves a great deal of credit for the detailed mechanical 

 design of the tube and his work in producing tube models. 



The development was under the over-all direction of Mr. J. R. Wilson 

 and Dr. S. B. Ingram. 



