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Analytical Foundation for Low-Frequency Power-Telephone Interference

01 May 1978

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This paper explores a systematic approach for understanding the electromagnetic interaction between power and telephone systems. Historically, the various mechanisms of coupling, shielding, and longitudinal-to-metallic conversion have evolved into separately addressed concerns. This has led to useful insight but somewhat narrow understanding, since the interdependence of the various concepts has received limited consideration. Moreover, since some of the classical treatments extend back over five decades, they are sometimes difficult to read owing to variations in terminology and basic units. We wish to provide a cohesive overview that emphasizes the interrelationship among these topics within a modern analytical setting. This approach, using concepts familiar to recent engineering graduates, unifies historical developments and provides a basis for understanding current viewpoints toward reducing power-telephone interaction. Although transmission line theory is briefly touched upon as a starting point, the basic framework consists of an analytical model that utilizes only lumped-element circuit theory. This lumped-element general analytical model serves the following purposes. First, it ties together within 1663