Digital radio - you've heard nothing yet!
By Bill Roberts, Secretary-General, North American Broadcasters Association (NABA)
Electronic Times Report, January 2000
While a host of new technologies have been stealing the media thunder, a quiet revolution is brewing in digital radio.
Imagine a portable digital radio, hand-held or installed in your vehicle, with none of the static and fade of analog radio. Imagine playing your chosen music with CD-quality sound from an enormous jukebox in the sky with limitless sampling possibilities.
Digital radio has been slow off the mark. It's not surprising, given the high cost of today's digital receivers. But that's about to change, driven by developments in Web-based technologies and advances in Digital Audio Broadcasting (DAB).
Internet radio
Streaming audio was one of the earliest forms of Web multimedia. Today, thousands of radio stations around the world stream live audio of their regular programming over the Internet and special recorded broadcasts not available elsewhere. The enabling technology is MPEG Audio Layer II digital compression. It allows a broadcaster to dramatically increase the number of signals per channel, and for those signals to arrive exactly as sent - sharp, clear, and undistorted.
Downloading near-CD quality music from the Web has been an underground phenomenon that's now going mainstream. In 1997, a group of college students, tired of paying for CDs with only one good cut, or wanting to hear their own kind of music, came up with their own Web-based music distribution system called MP3. It made it easy to create digital files of a song from a CD and share it with like-minded enthusiasts on the Web.
Today, the largest MP3 web site features licensed content produced by over 23,000 artists, with 200 more being added a day. The major record companies haven't participated, since MP3 today has no means to prevent redistribution. However, they quickly learned the power of the Web for distribution.
So the industry is working on a standard for MP3 music delivery called SDMI (Secure Digital Music Initiative), that promises security and rights management for music labels. It uses an embedded numbering system, like ISAN (International Standard Audiovisual Number).
Last year saw the first portable MP3 audio players on the market. These pager-sized music boxes store music from personal CDs or the Web in flash card memory. Impervious to vibration, they're ideal for personal sports. They can even be connected to a home stereo or car radio for amplified sound.
Digital Audio Broadcast (DAB)
Like Internet radio, DAB relies on the MPEG Audio Layer II system to achieve compression without perceptible loss of quality to the broadcast signal. The most obvious benefit to listeners is DAB's ability to deliver robust and reliable CD-quality stereo sound, especially to mobile receivers. Electromagnetic interference from power lines and thunderstorms, and multipath interference from hills and buildings, do not deteriorate DAB signals. Since a single DAB frequency can carry the same signal across an entire network, drivers can cross the country without changing the radio dial.
Text and image displays on DAB receivers complement the listening experience with information such as song title, lyrics and artist, as well as traffic, weather, sports, or stock market updates.
Regular DAB services currently cover at least 30% of the population in most European countries, using the L-Band transmission standard Eureka 147, a broadcasting spectrum adopted by most of the world. In the UK, 60% of listeners can receive BBC's digital radio broadcasts.
Canada remains at the forefront of Eureka 147 developments. The CRTC automatically grants DAB licenses to every existing station, on the premise that DAB is considered a replacement technology. Currently, 19 radio stations operate DAB services from Toronto's CN Tower. In Vancouver there are seven DAB radio stations and in Montreal, nine radio stations operate full time DAB service.
In the US, the broadcast industry has opted for a system called In-Band On-Channel (IBOC) digital radio, that uses the current radio spectrum to transmit existing FM and AM analog signals simultaneously with digital signals. This technology allows broadcasters and listeners to move from analog to digital without changing current dial positions.
Japan has not decided which digital radio system to adopt. While receiver manufacturers favour Eureka 147, the government is evaluating an NHK in-band alternative and continues to monitor developments in the US.
Convergence
Both PC-card and software-only DAB receivers have been developed, allowing DAB broadcasts to be played over computer speakers.
A portable DAB receiver with docking MP3 player could replace today's AM/FM radio with CD player/changer. Instead of CD's, there are flash memory cards the size of postage stamps.
Then there's the integration of the cell phone with DAB. There are already headphones playing DAB music on the market in Korea and under development in Sweden.
DAB can be used to provide TV in moving vehicles, with picture quality better than conventional TV. DAB can also help car navigation systems steer around traffic jams by continuously updating traffic conditions.
The possibilities and the potential of digital broadcasting are exhilarating.
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