VOLUME xxvn JANUARY, 1948 no. i 



p^TTHE BELL SYSTEM 



TECHNICAL JOURNAL 



DEVOTED TO THE SCIENTIFIC AND ENGINEERING ASPECTS 

 OF ELECTRICAL COMMUNICATION 



An Experimental Multichannel Pulse Code Modulation 

 System of Toll Quality 



L. A, Meacham and E. Peterson 1 



Electron Beam Deflection Tube for Pulse Code Modulation 



R, W. Sears 44 



Metallic Delay Lenses Winston E, Kock 58 



A Non -reflecting Branching Filter for Microwaves 



W, D, Lewis and L, C. Tillotson 83 



A Note on a Parallel-Tuned Transformer Design 



F. C. Rideout 96 



Statistical Properties of a Sine Wave Plus Random Noise 



S. O. Rice 109 



Noise in Resistances and Electron Streams. ..J.R, Pierce 158 



Abstracts of Technical Articles by Bell System Authors ... 175 



Contributors to this Issue 181 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



NEW YORK 



50^ per copy $1.50 per Year 



