Optimized Compatible AM Stereo Broadcast System

A two-channel multiplex system for compatible AM broadcasting is described. System objectives including compatibility, service area, and program quality are discussed. Three different methods of creating the equivalent transmitted signal are reported, and conversion of present-day monaural stations to stereo by each method is indicated. The design of receivers for recovering the two stereo tracks is examined showing the signals derived by various means of detection. Emphasis is placed on a design resulting in a reliable, minimum cost receiver. Field test equipment and results are briefly considered and the level of performance that can be obtained from the system is stated.