Digital Radio Revving Up
The Internet as a digital broadcast medium has also been garnering generous attention with its 1700 or so web-based stations or rebroadcasts of radio stations. But with the low bandwidth inherent in a web connection, sound quality takes a back seat to the novelty of hearing your local DJ while on vacation in Guam. Digital Audio Broadcasts (DAB) in the US are designed to take existing radio-spectrum allocations and add a "CD-quality" compressed 96kHz digital stream (known as In-Band On-Channel, or IBOC) for simultaneous broadcast over the airwaves. IBOC DAB is both backward- and forward-compatible, meaning that current AM/FM receivers will not be affected. And when a station decides to turn off the analog signal sometime in the future, IBOC DAB-compatible receivers will operate with the remaining all-digital signal.
Last week, Lucent Digital Radio, a new venture of Lucent Technologies, announced that it will commence field testing in the US of its digital audio broadcast (DAB) systems in early 1999. Currently in development, the Lucent Digital Radio IBOC systems will be tested through the end of 1999, by which time the AM and FM IBOC systems are expected to be fully developed and tested. The testing cycles will begin with the Lucent Digital Radio FM system, and will later include testing of the company's AM IBOC system in mid-1999.
"Digital audio broadcast is an extension of the world's digital communications revolution that we're leading," said Suren Pai, president of Lucent Digital Radio. According to Lucent, their IBOC system will provide interference-free reception and new data services (e.g., song titles shown on a radio display). It also features their Perceptual Audio Decoder (PAC), developed by Bell Labs, which converts a radio station's analog signal into digital for rebroadcast.
"Lucent Digital Radio will begin large-scale testing of a system design to turn IBOC into commercially viable products for the marketplace," said Alan Pate, director of technology planning for Lucent Digital Radio. "We will start hard-core testing in multiple environments to measure the robustness of our system. The key to the success of IBOC is the integration of audio and channel coding technologies into a system that can effectively resist multipath and interference conditions. Lucent's IBOC technology places both high-capacity digital and analog signals within the existing spectrum. The IBOC approach will allow broadcasters to rapidly introduce digital sound to listeners on their current dial positions using existing transmitters and antennas."
In Britain, the BBC began testing a DAB system back in 1995. The BBC estimates that nearly 60% of its audience is currently covered. Three digital radio tuners have been introduced that retail at around £800 ($1350); cheaper portable radios are planned for next year. A consortium named Digital One plans to begin commercial DAB radio broadcasts in Britain on October 1, 1999, and has already invested millions of pounds in promoting the new format. Digital One says it will eventually reach 85% of all Britons by the year 2002, with 69% being covered when the service is launched.
"For the first time in history, commercial radio will be on a level playing field with the BBC nationally," said Digital One's Chairman, Ralph Bernard. "Now we have the opportunity to increase our audience and revenues, and to become the dominant force in the 21st century." Initial broadcasts will include transmissions from three commercial stations---Classic FM, Talk Radio, and Virgin---with an additional seven channels planned.