Selection of a carrier relaying system

TWO BASIC TYPES OF carrier relaying systems are available today. These are the power-directional-comparison system and the phase-comparison system. With two distinct basic systems to select from, the relay engineer is confronted with the necessity of making a choice between them for any application where use of a carrier-pilot system is indicated. The purpose of this article is to discuss the relative advantages and limitations of each system and to point out certain considerations that have a bearing on the choice of a system for a specific application.