As a result, the NRSC has suspended its digital radio standards-setting process, which is vital to the launch of new radio sets. The NRSC says digital radio cannot be rolled out to consumers until iBiquity Digital of Columbia, Maryland- the company that is providing the digital technology- gets it right.
iBiquity Digital planned to use a technology called in-band, on-channel (IBOC) broadcasting that squeezes both the old analogue radio and the new digital radio signals into the frequencies currently used by AM and FM channels. Listeners would need an IBOC-compatible radio to receive the digital signals, but these cannot be manufactured until the NRSC sets the standards.
The official suspension of the standards is a victory for the Amherst Alliance, a protest group that includes broadcasters, audio webcasters and what spokesman Donald Schellhardt calls "good old-fashioned concerned citizens".
Last October, Amherst petitioned the US Federal Communications Commission to abandon IBOC and test alternative systems, such as the proven European Eureka system that has been adopted, or is being adopted, by most other countries.
iBiquity Digital was formed two years ago from the merger of Lucent Digital Radio, a division of Lucent Technologies, and USA Digital Radio. IBOC uses Lucent's Perceptual Audio Coder (PAC) software to compress sound into very slow digital data streams- similar to that of a fast dial-up modem. PAC constantly analyses the sound and throws away what it calculates the ear doesn't need to hear.
The overriding advantage is that the data rates are so slow that the digital signal can be broadcast alongside existing analogue AM and FM stations, without the need for extra radio frequencies. iBiquity claims "richer-sounding music" and "compact-disc-like quality". But Amherst has warned all along that the sound quality of IBOC is poor and that its signals will interfere with analogue radio. NRSC now agrees.
There are "growing concerns over the audio quality", says the NRSC, blaming "poor performance" of the technology at low digital bit rates. This raises concerns over performance at higher bit rates. When bit rates are too low, digital sound becomes coarse, like cellphone sound. Crucially, the signal can also interfere with the standard AM or FM radio signal it sits beside.
By contrast, Europe's Eureka-based Digital Audio Broadcasting system uses much higher data rates- up to 196 kilobits per second- and needs completely new frequencies to carry the high-speed signals. Amherst says eight years of broadcasts and booming sales of digital radios in the UK have proven Eureka's sound quality to be good, largely free of interference and "superior" to IBOC.
In February this year, the powerful National Association of Broadcasters (NAB) accused Amherst of trying to "throw sand in the gears" with "frivolous charges and makeweight issues". But now the NRSC, which is sponsored by the NAB, has thrown its own sand by complaining about the IBOC sound quality and freezing official approval unless it improves.
Charles Hutton, a radio engineer from Seattle who works with the Amherst Alliance, says: "I'm amazed at the NRSC's decision. Everyone thought IBOC audio quality was mediocre at best...Finally the Emperor was found to have no clothes."
iBiquity says it concurs with the NRSC's decision to delay roll-out of digital radio. "We have an ongoing improvement plan," says a spokesman.
Author: Barry Fox
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New Scientist issue: 31 MAY 2003
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