Analytical Foundation for Low-Frequency Power-Telephone Interference

The mechanisms of interference at voice-band frequencies from a power distribution system which adversely affect the telephone loop plant are systematically described. A unified derivation is presented of simple lumped-element circuit models for telephone plant coupling, shielding, and longitudinal-to-metallic conversion. This approach establishes both qualitative understanding and quantitative analytical tools for characterizing the effects of low frequency interference. A glossary is included which represents a consensus evaluation of the best contemporary relationship between historical terminology and modern analytical viewpoints.