Digital Radio Proponents Cite Gains

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The developers of competing terrestrial digital audio radio (DAR) standards delivered status reports on their technologies during the NAB convention, where Lucent Digital Radio announced successful results of field test with three radio stations.

For its part, USA Digital Radio (USADR) announced a technology and marketing development agreement with a second receiver maker, Sanyo Electric. USADR reached a similar agreement last year with Kenwood.

USADR also announced that two more transmission-equipment makers, Jampro and Armstrong, have agreed to develop and test broadcast equipment incorporating USADR's technology. That brings the number of USADR-allied equipment makers to 14, representing "all the major players" in each link in a station's broadcast-equipment chain, USADR president Robert Struble told TWICE.

USADR and Lucent are promoting separate, incompatible in-band on-channel (IBOC) technologies that would let existing AM and FM stations use their existing transmitters, antennas and dial positions to deliver digital programs over the air. IBOC technology would also let broadcasters simultaneously deliver analog and digital broadcasts on their assigned frequencies to ensure that consumers' existing radios don't become obsolete overnight.

By the end of the year, the FCC is expected to develop rules for initiating terrestrial digital service, which observers believe will mandate the use of one of the competing IBOC technologies. Broadcasts could begin next year.

During NAB, both companies demonstrated on-the-road reception of their competing standards by using demo vehicles equipped to receive digital broadcasts from separate Las Vegas radio stations.

Also at the event, Lucent Digital Radio president Suren Pai declared that continuing field tests of Lucent's multistreaming technology have shown it to deliver digital signals "to the very edge of [a station's] analog coverage." He added, "No one believed we could do it."

The tests uncovered "no discernible interference" to a broadcaster's analog host signal, added senior VP Ben Benjamin.

The tests, Pai continued, also demonstrated the technology's "graceful degradation of audio quality" with "no digital dropout" in difficult reception conditions. Lucent said it achieves that goal by transmitting four audio streams at a combined audio data rate up to 128kbps. If one to three streams drops out, reception continues at a lower quality level.

Because multistreaming doesn't use a station's analog signal as a digital-signal backup, the technology makes it possible for FM broadcasters to transmit a digital program whose content would differ from that of an analog program transmitted simultaneously, Benjamin noted. That potentially increases programming choices for consumers, Pai noted.

USADR, in contrast, blends in a station's analog signal during digital dropouts. If a station converts to digital-only service, the digital signal is backed up by a second digital signal containing the same content.

In his status report, USADR president Struble said the Sanyo agreement would enable the receiver maker "to begin the process that will enable them to develop receivers." The agreement calls for a transfer of technology to Sanyo so it can determine how to implement IBOC in its product mix, he said.

Lucent also has two development agreements, which were previously announced, with receiver makers Harman Kardon and Recoton.

USADR's owners include 16 of the largest radio broadcasters in the U.S., including the top 10 and 15 of the top 20, Struble said. Other investors include broadcast-equipment maker Harris and Texas Instruments.

USADR has conducted successful field tests with eight stations, Struble noted.

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