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c^.s^ TM¥ BELL SYSTEM 



TECHNICAL JOURNAL 



A JOURNAL DEVOTED TO THE 

 ■:v SCIENTIFIC AND ENGINEERING 

 ^N^-' ASPECTS OF ELECTRICAL 

 COMMUNICATION 



ADVISORY BOARD 



S. Brackev F. R. Kappel 



M. J. Kelly 



EDITORIAL COMMITTEE 



E. L GREENf, Chairman 

 A. J. BuscH F. R. Lack 



W. H. DoHERTY J. W. McRae 



G. D. Edwards W. H. Nunn 



J. B. FisK H. I. RoMNEs 



R. K. Honaman H. V. Schmidt 



EDITORIAL STAFF 



Philip C. Jones, Editor M. E. Strieby, Managing Editor 



R. L. Shepherd, Production Editor 



INDEX 

 VOLUME XXXI 



1952 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 

 NEW YORK 



