CES Report 4 - Digital Terrestrial Radio at CES
Digital Radio May Finally Happen in the U.S. - After almost a decade of horsing around, terrestrial radio broadcasting may finally join in the digital age, according to a display at the 2002 Consumer Electronics Show in Las Vegas. The National Radio Systems Committee - jointly sponsored by the Consumer Electronics Association and the National Association of Broadcasters - has evaluated the test data on the iBiquity FM IBOC digital system (In-Band On-Channel) and finds it represents a significant improvement over existing analog services as well as over earlier in-band DAB systems that were tested by the FCC and found wanting. The enhancements include almost total freedom from typical FM multipath distortion, significantly improved full-stereo coverage (without having to mix to nearly mono as do most car FM receivers), flexible data-casting opportunities, and an efficient way for FM stations to begin the transition to digital broadcasting (as TV stations are doing with DTV).
The main cause of the long haul to digital radio in this country was the insistence of broadcasters, and especially the NAB, that the digital signal be carried at the same frequency as their present FM signal rather than at an entirely new higher frequency (as is being done with DTV). Other countries such as Britain and Canada have adopted DAB systems using different frequencies, thus eliminating the tradeoffs of possible interference not only between the analog and digital signals of the same station but between adjacent stations on the dial. The NRSC evaluation shows that a small decrease in signal-to-noise will be evident for some listeners in areas where adjacent stations operating with the FM IBOC system overlap the coverage of the desired station. But they say these listeners may also be subject to adjacent-channel analog interference which will mask the digital interference. They also mention the stereo blend-to-mono function included on all car receivers (as mentioned above), which they feel will also mask any IBOC-related interference. Oh boy...
The NRSC has recommended that the iBiquity FM IBOC system now be authorized by the FCC to speed up the transition to DAB in the U.S. With minimal impact on the existing analog FM reception and no requirement for new frequencies. Among the owners of iBiquity Digital are 14 of the nation's top 20 radio broadcasters and leading broadcast technology companies such as Harris and Lucent. The broadcasters operate more than 2000 radio stations in the U.S. There is also an AM version of the iBiquity system, and the data functions include a small screen display on the DAB receivers which can display advertising, CD covers and information, interactive commerce, more info on subjects mentioned on broadcasts, and on-demand local traffic and weather, sports, stock quotes and event schedules.
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