Excerpt from Radio Communication, Theory and Methods: With an Appendix on Transmission Over Wires
This book is the substance of a course of lectures given by the author during the summer of 1917 to a Company of the U. S. Reserve Signal Corps troops. From the employees of the Western Electric Company who had volunteered for service two companies were formed, one at Hawthorne, Ills., and the other at New York City. These men were retained on the pay roll of the Company and their training was carried out on company time by other employees. In radio-communication this training consisted in part of the course of lectures mentioned above and in part of laboratory work. To Major Jewett, Chief Engineer of the Western Electric Company, the author is indebted for this opportunity of assisting in the training of our Expeditionary Forces. It is in the hope that the method of presentation, found acceptable to this Signal Corps Company, may be of wider use that this text is published.
The individual men to whom the lectures were given differed widely in the extent of their previous training in electrical engineering. The author, therefore, adopted a method which involved practically no mathematics except elementary algebra and presupposed but a limited knowledge of physics. (This method solves problems like that of determining the natural frequencies of tuned and coupled circuits or that of finding the effective value of a sinusoid.) Described in mathematical terms it consists in the development and use of two concepts, namely, that of the vector operator "j" and the differential operator "p." Since all the functions with which the radio-engineer has to deal are expressible in exponential form by the use of "j," only one very special case of the operator "p" need be considered. With a knowledge of this one case, which may be developed in an elementary manner, the student becomes equipped with tools of analysis which in some school curricula are delivered to him only through a two years' drill in calculus, and differential equations.
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