VOLUME XVn OCTOBER, 1938 number 4 



THE BELL SYSTEM 



TECHNICAL JOURNAL 



DEVOTED TO THE SCEENTinC AND ENGINEERING ASPECTS 

 OF ELECTRICAL COMMUNICATION 



Ultra-Short Wave Transmission and Atmospheric Irregularities 



— C. R, Englund, A, B. Crawford and W, W. Mumford 489 



Amplitude Range Control — S. B. Wright 520 



Devices for Controlling Amplitude Characteristics of Tele- 

 phonic Signals — A, C, Norwine 539 



The Exponential Transmission Line — Chas. R, Burrows . .555 

 The Bridge Stabilized Oscillator — L, A. Meacham .... 574 



Effect of Space Charge and Transit Time on the Shot Noise 

 in Diodes — A. J, Rack 592 



Fundamentals of Teletypewriters Used in the Bell System 



— £. F, Watson 620 



The Dielectric Properties of Insulating Materials 



— E» J. Murphy and S, O. Morgan 640 



Abstracts of Technical Papers 670 



Contributors to this Issue 673 



AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



NEW YORK 



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