Present Practice in the Synchronous Operation of Broadcast Stations as Exemplified by WBBM and KFAB

This paper briefly covers the history of synchronization of broadcast stations in the United States and abroad. The WBZ-WBZA system, as developed by Westinghouse, is described as typical of the "derived-carrier" type of synchronization. A new system of synchronization and equipment, developed by Bell Telephone Laboratories and the Western Electric Company and used successfully by WBBM and KFAB for the past year, is described in detail. In this system the station carriers are continuously compared and continuously and automatically corrected to a reference standard frequency transmitted by wire line.