An experimental system of FM data-broadcasting

An FM data broadcasting system in which data signals are multiplexed with an existing FM stereophonic broadcast is described. Signal multiplexing is accomplished by means of a supplementary subcarrier, which is amplitude-modulated through phase shift keying. Digital code signals identifying the broadcasting station, type of program, weather forecasts, or news are provided together with the FM program. By using these code signals, information is displayed at the receiver on a character display device, and the FM program can be automatically received and recorded. The technical feasibility of, and service configuration for, FM data broadcasting were investigated. An error correcting code is described and assessed.