AT&T enters EIA digital audio test; two receivers built

Electronic News, July 19, 1993 by Jack Robertson

WASHINGTON--AT&T is a late entry in the battle to set global standards for digital audio radios--against several European consumer electronics models--in tests to be launched this fall by the Electronic Industries Association.

An AT&T official last week confirmed the giant carrier has built two prototype digital audio receivers that will be tested against a European consortium model from Philips/Thompson/Grundig/Telefunken and two models using the European Musicom digital audio technology.

Nikio Jayant, AT&T project director, said AT&T has developed a new digital audio compression technique that allows transmission at a much lower rate of 64-or 128-kilobits/second than the rival European systems being tested. "This conserves spectrum in transmitting the signal, as well as offering greater multimedia opportunities," he said.

Mr. Jayant said AT&T hopes to establish its digital audio compression system as the world standard for all the emerging markets--digital audio broadcast, advanced television, multimedia, and land-line telecommunications.

The vast business potential of licensing its technology into these new markets is driving the AT&T program. "AT&T isn't planning to get into the radio receiver business, although that isn't totally out of the question," Mr. Jayant added.

AT&T is one of two American contenders in the EIA digital audio testing--a prototype receiver developed jointly by the Voice of America and NASA Jet Propulsion Laboratory will also be tested. That radio, however, solely concentrates on direct audio broadcast satellites--the only receiver in the tests for that purpose.

Sources said AT&T uses its own digital signal processor devices and its own compression algorithm to get the lower bit rates. Mr. Jayant said technical details of the AT&T receiver are still under wraps, although some information will be disclosed when the firm submits its unit to EIA for testing in October.

The Voice of America/JPL digital receiver can use any of the competing digital audio compression schemes, said Donald Messner, VOA engineering director on the project. He said the receiver concentrates on technologies needed for digital audio broadcast satellites, and can work with the AT&T or European compression algorithms.

The VOA/JPL receiver has already demonstrated preliminary capability of receiving digital audio signals from satellites, using a channel from the NASA Tracking and Data Relay Satellites now in orbit.

EIA will use the NASA Lewis Research Center, Cleveland, for its testing. Additional propagation tests will be done in Charlotte, N.C. and Seattle, Wash. EIA will characterize each system tested, and that data will be used for adopting an ultimate single digital audio receiver standard for the U.S.

The four contenders are AT&T with an in-band on-channel receiver and an alternate in-band adjacent receiver; the European Eureka consortium lead by Thomson; the VOA/JPL satellite receiver; and separate AM and FM receivers from USA Digital--a consortium of Gannett Newspapers/Westinghouse Group W/CBS with receivers based on the Europe's Musicom compression system.

AT&T reportedly hopes its digital audio standard will be selected, and ultimately be adopted for the U.S. ATV system as well. AT&T developed its system too late to be considered in the U.S. tests for ATV.

Even when a new combined ATV prototype is being developed from four original contenders, the ground rules for ATV testing specified that only digital audio systems originally proposed would be considered. That includes Musicom of Europe, Dolby, or a concept from the Massachusetts Institute of Technology.