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Receivers race to catch digital revolution on the radio
By Glenn Fleishman
Published: July 28, 2005
New York Times
Plug a set of headphones into a radio tuned to an FM jazz station. Hear the hiss at the bottom of the range and the fuzz at the top. Remember why you like compact discs.
But don't be impatient: wait eight seconds. An "HD" light appears on the tuner. And now the bottom drops out. The hiss turns to silence. The stereo channels separate, opening a cramped room into a performance hall. And the high fuzz is now crisp high notes from a trumpet or Ella Fitzgerald.
You have just heard terrestrial digital radio. Or you would have - if you could get your hands on a receiver.
Satellite digital radio has captured the attention of consumers and investors with its billions spent and millions of paying subscribers. But a quiet digital revolution has hit the AM and FM dials as well: more than 450 stations in the United States now broadcast one or two digital channels alongside analog ones. At least 2,000 of the more than 12,000 stations in the country are committed to adding the format.
The technology to make this happen - called in-band on-channel, or IBOC - hides digital signals at low power in the spaces between stations. Only one company's technology has been approved by the Federal Communications Commission: HD Radio from iBiquity Digital. (IBiquity says HD does not stand for high definition - or anything else.)
Digital AM sounds like present-day stereo analog FM. Digital FM not only improves fidelity and stereo reception, providing a dynamic audio range approaching that of a compact disc, but also makes use of enough bandwidth to allow multiple channels.
An HD Radio tuner takes eight seconds to lock onto and start playing a digital stream; the analog broadcast seamlessly switches into richer audio, providing a demonstration of its improved quality.
Unlike satellite radio, digital AM and FM are free to listeners. But only a few tens of thousands of car tuners equipped to decode the signals have been sold in the 18 months since the first product was shipped, according to Dan Benjamin, a senior analyst at ABI Research in Oyster Bay, N.Y. Home tuners are just reaching the market.
NEW YORK TIMES
Kenwood, the earliest HD Radio maker, has 40 models compatible with an adapter (top). Yamaha released the first home digital radio, the RX-V4600 (bottom).
How digital radio works
IBOC uses a part of the spectrum just outside the frequency used for a radio station's conventional signals.
HD Radio is capable of great range with a small fraction of the power of analog radio. In a test by National Public Radio and WNYC-FM, a 57-watt transmitter on the Empire State Building reached almost all of WNYC's coverage area, with a population of 16 million, according to Mike Starling, NPR's vice president for engineering.
The technology sends multiple streams of data over very narrow frequencies to solve the problems of analog AM and FM reception. The streams are separately received, synchronized and assembled by the radio tuner.
In AM, this avoids having signals fade in short tunnels and will prevent noise from electrical motors. "It gets rid of the majority of problems with AM radio," said Thomas R. Ray III, director of engineering for Buckley Broadcasting and WOR-AM, a commercial talk-radio station in New York that has added digital transmissions.
With FM stations, multipath reflection can be controlled with HD Radio, avoiding audible echoes from signals bouncing off buildings. "You don't get that sort of 'fumth-th-th-fumth' sound," said Stephen Shenefield, director of product development at Boston Acoustics, an audio equipment manufacturer.
FM radio has a larger spread of unused spectrum, and National Public Radio and public radio stations successfully pushed the F.C.C. to allow multicasting, or multiple digital channels of different quality for existing stations. The F.C.C. allows a second digital channel with a waiver; up to five channels may be permitted in the future.
What's on
Public radio produces much more programming than its member stations can broadcast: 300 hours a week, Mr. Starling of NPR said. NPR is now offering five full-time music streams to stations for HD Radio multicasting as well. "If we had more shelf space, we could do more format focusing," Mr. Starling said.
KUOW-FM in Seattle broadcasts what it calls KUOW2, a full slate of reruns of local and network programs with a dedicated host.
Commercial broadcasters, too, are taking note. Clear Channel, which owns 1,200 stations, says it is committed to taking 95 percent of its stations in the top 100 markets digital within three years. Among the attractions is HD Radio's ability to deliver data streams alongside audio. The system can already carry program-associated data, like a song title, artist and album name. But the capacity exists for much more.
Robert J. Struble, chairman and chief executive of iBiquity, noted that the text of advertising messages could be synchronized to display on a radio's readout as a related commercial was broadcast. Other uses include traffic updates for car navigation systems and private commercial data transmissions.
A future version of the technology will feature a data uplink that could let stations have a "buy now" button for songs. "There's no better place to make an impulse purchase than when I'm sitting in traffic," Mr. Struble said.
HD Radio has the potential to limit access to certain channels by receiver serial number, much as with satellite digital radio, so that specific programming could be delivered for a fee.
Mr. Starling mused that the "buy now" button might read "pledge now" for public radio stations, and that a station could allow only listeners who donate funds to tune to a digital channel free of fund-raising during pledge drives.
How to listen
HD Radio was limited to car receivers from its retail introduction in January 2004 until June 2005. The earliest HD Radio manufacturer, Kenwood (kenwoodusa.com), now has 40 models compatible with a $399 HD Radio adapter; other makers have a few products released, but a flood is in the pipeline. A representative of Visteon, a major automotive systems supplier, said automakers could offer HD Radio as an option in the 2006 model year.
Yamaha (www.yamaha.com) released the first home radio in June, its RX-V4600 ($1,900), a home entertainment centerpiece. In tests of all Seattle-area FM HD Radio stations using the Yamaha unit, the results were breathtaking. Tuning in secondary multicast channels, however, required use of the remote control and was awkward.
Three companies plan simpler tabletop tables, each of which will add multicast digital stations sequentially: turning the dial will tune through those secondary stations.
The Radiosophy receiver docks in a speaker unit; together, the two parts cost $259 direct from the company, including shipping. Radiosophy expects to offer a car adapter kit later. The receiver includes analog and digital optical outputs. The company (www.radiosophy.com) expects to ship the product in September.
The Recepter Radio HD ($499) made by Boston Acoustics (www .bostonacoustics.com) has a single built-in speaker and a satellite speaker to produce stereo audio. It is also a clock radio, and has stereo input and multiple outputs. The radio should be available in late August.
Polk Audio has built HD Radio into a more elaborate all-in-one entertainment system that includes a CD and DVD player and speakers, and multiple inputs and outputs. The $599 unit, called the I-Sonic, is also equipped for satellite XM Radio through a plug-in module. Polk Audio has delayed shipping until late in the year (www.polkaudio.com).
No one in the industry expects to replace a billion analog radios overnight. Even Mr. Struble of iBiquity put the most optimistic date for an analog shutdown as 12 years from now, though he thought that was unlikely.
Still, there are already listeners, however few. "The last time we had to shut down the HD - off for any reason - we had eight phone calls," Mr. Ray of WOR said. "People wanted to know why."
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