ATSC: DTV will travel

Standards body seeks portable reception of 8-VSB

After hearing broadcasters grumble for months that they want a digital TV system that will allow reception on the go, the Advanced Television Systems Committee last week launched a proceeding to improve the beleaguered 8-VSB transmission standard.

ATSC Executive Director Mark Richer says the decision was based on work done by RF task force.

"Broadcasters have defined terms such as fixed, portable, pedestrian and mobile reception," says Richer. "Clearly mobile is the most challenging and will also take the most tradeoffs."

Chip makers Zenith, Philips and NxtWave Communications are working on VSB systems that permit receivers that users could carry around or even install in their cars. Broadcasters' interest in such receivers has grown along with their interest in datacasting.

The chip makers say the solutions involve a tradeoff, however. To make reception more "robust," capable of at least portable reception, developers will have to give up part of the 19.7- Mb/s data stream now reserved for TV or other content.

NxtWave President and CEO Matt Miller says that every 1 Mb/s of "robust" transmission costs roughly 2 Mb/s of fixed transmission. "But if you can get 3.5 Mb/s robust and 12.5 normal [in a DTV signal], that's pretty interesting."

Some broadcasters believe 8-VSB cannot be improved and should be replaced with the European COFDM system. One COFDM backer, Sinclair's Nat Ostroff, says he's "grateful" that the ATSC has recognized the need for improved reception. But, he adds, "I am concerned that what they are doing is not just a cynical strategy to sidetrack any efforts to find a true solution."

FCC Chairman Bill Kennard last week warned against any changes in the DTV system that would delay service. "It's important for the broadcast industry to just get on with it."