Experimental Results of 20-Mb/s FSK Digital Transmission on 4-GHz (TD) Radio

The growth of Dataphone* Digital Service1 (DDS)+ and the needs of new services such as Picturephone* Meeting Service2 (PMS) require a substantial increase in digital long-haul transmission capacity. The existing long-haul digital facilities, mainly Data-Under-Voice3 (DUV), are near exhaustion in many areas. Furthermore, some existing frequency modulation (FM) radios will be replaced by the single-sideband * Service mark of AT&T. Acronyms and abbreviations are defined in the Glossary at the back of this paper. * Service mark of AT&T. f 1209 TO FM T E R M I N A L SIX DS-1 CHANNELS SIX AUXILIARY CHANNELS Fig. 1--The 20-Mb/s terminal.