VOLUME XXIX JANUARY, 1950 no. i 



THE BELL SYSTEM '^ - 



■2.3 Cn 



TECHNICAL JOURNAL 



DEVOTED TO THE SCIENTIFIC AND ENGINEERING ASPECTS 

 OF ELECTRICAL COMMUNICATION 



Traveling-Wave Tubes J. R. Pierce 1 



Communication in the Presence of Noise — ^Probability of 

 Error for Two Encoding Schemes ;S. 0. Rice 60 



Realization of a Constant Phase Difference 



Sidney Darlington 94 



Conversion of Concentrated Loads on Wood Crossarms to 

 Loads Distributed at Each Pin Position 



R. C. Eggleston 105 



The Linear Theory of Fluctuations Arising from Diffusional 

 Mechanisms — ^An Attempt at a Theory of Contact 

 Noise J. M. Richardson 117 



Abstracts of Technical Articles by Bell System Authors 142 



Contributors to this Issue 146 



50^ Copyright, 1950 $1.50 



per copy American Telephone and Telegraph Company per Year 



