LU could be a pioneer in digital radio.
Digital radio's ready to be put to the test
By George Leopold
WASHINGTON -- An industry partnership formed to develop digital radio technology plans field tests this year for an in-band, on-channel (IBOC) digital-audio broadcasting system which uses existing commercial frequencies to transmit digital audio signals. Backers claim the technology overcomes the shortcomings of earlier IBOC systems, which fared poorly in field tests conducted by the Consumer Electronics Manufacturers Association (CEMA, Arlington, Va.) and marks a significant new effort to tune into this digital consumer-electronics market.
In a test report filed with the Federal Communications Commission earlier this month, CEMA endorsed the European-designed Eureka-147 system, which operates in the L-band used by the U.S. military, as the only digital-audio broadcast system tested to date that offers adequate audio quality and signal performance. But IBOC-technology partners USA Digital Radio (Linthicum, Md.) and Lucent Technologies (Murray Hill, N.J.) say their system, which fits the digital signal within the bandwidth of existing AM and FM stations, will be a leading contender when the FCC authorizes digital radio broadcasting in the next several years.
Regulators are looking for a digital system that offers consumers CD-quality sound without compelling them to hunt for their favorite stations. That could give IBOC a competitive edge over rival technologies, its proponents assert.
A European research consortium developed Eureka-147's L-band approach. AT&T is developing an in-band system that puts the digital signal in the adjacent channels between FM stations. And the Voice of America and the Jet Propulsion Laboratory are codeveloping a satellite system that will operate in the S-band.
FCC officials, who will ultimately have to decide when to authorize digital-audio broadcasting and whether to set a U.S. standard, appear bullish on the improved IBOC technology. Keith Larson, assistant chief of the FCC's Mass Media Bureau, acknowledged that"significant development work" has taken place. While no testing schedule has been set, Larson said the Commission could take up the digital-audio broadcasting issue as early as later this year.
Lucent and USA Digital Radio, a joint venture between Westinghouse Electric Corp. and Gannett Co. Inc., linked up on IBOC development in May after older IBOC systems failed to satisfy CEMA requirements. According to CEMA's field-test report, those earlier approaches proved deficient in audio quality, performance with channel impairments, RF compatibility and coverage.
Heading for the field
USA Digital and Lucent expect to begin field testing their improved IBOC system "in the latter part of this year," said USA Digital vice president Jeff Jury. Meanwhile, they are readying the system for laboratory testing and simulations, pinpointing stations around the country for field tests and working with IC-receiver manufacturers.
USA Digital has been developing an IBOC system since 1990. The first live IBOC broadcasts in AM and FM were staged at the 1995 National Association of Broadcasters show in Las Vegas.
Lucent is contributing perceptual audio coding (PAC) technology first developed by its Bell Laboratories arm. The PAC algorithm uses acoustic modeling based on the human auditory system to achieve superior signal-compression ratios. The algorithm's compression efficiency is expected to boost IBOC performance in digital radio broadcasting, developers said.
Still, there's work to be done before industry consensus on digital radio can be forged. "Obviously, we have to come to a meeting of the minds with CEMA," said USA Digital's Jury.
CEMA last year halted efforts to win adoption of a U.S. digital radio system, doing so at the request of broadcasters, which wanted more time to correct the IBOC system. "We look forward to broadcasters demonstrating in the near future a system that will work," said Gary Shapiro, CEMA president.
With that in mind, the IBOC developers are mapping a test strategy that will demonstrate the system's ability to work in different broadcast environments around the country. The field-test plan calls for demonstrating the IBOC system in different cities that mirror the operating environments in most of the nation's approximately 11,400 AM and FM stations.
"This won't work if you test [IBOC] in only one city," Jury said. |
