A leaked draft of a subcommittee report by the Advanced Television Systems Committee suggests the 8-VSB digital television standards' multipath problems might not be able to be fixed affordably-and creates an awkward situation for the ATSC, which pushed for the standard in the first place.
But Robert Graves, ATSC chairman, stressed last week that the report has no status as an ATSC document and should not be considered further proof that 8-VSB modulation is in trouble.
"It's balderdash that this report puts 8-VSB in doubt," he says "I won't comment on the report, because it doesn't even represent the considered views of the author. It's a starting point for the debate, and quite evidently someone wanted to harm this deliberative process."
The draft, entitled "Performance Assessment of the ATSC Transmission System, Equipment and Future Directions," was written by VSB Performance Ad Hoc Group Chairman Frank Eory. Among the more damaging statements made in the report is that further gains in receiver performance are possible, but that with existing architectures and algorithms the improvements would be incremental rather than revolutionary.
"If and when solutions to the low K-factor dynamic multipath problem are discovered, the cost of implementing these solutions may be a significant impediment to market acceptance," the report adds.
Mark Hyman, Sinclair Broadcast Group vice president of corporate relations, says that, even though the report is a draft, it's still pretty eye-opening. "I don't know what else to add; the report speaks for itself." Sinclair has been the leading proponent of the alternative digital standard, COFDM. After Sinclair and others raised concerns about reception of the 8-VSB signal, particularly by portable and mobile sets, the ATSC decided to take a new look at 8-VSB.
Graves said the draft doesn't represent Eory's final opinion or the input of the working group. "It's very disruptive to the work of the committee to have this happen." More than 100 people have seen the document, with an agreement to keep it confidential. "You don't even have to be a member of ATSC," he said. "The only thing you have to do is pledge not to do what someone has done."
Graves says the report will be modified and refined before being presented to the task force itself. "This report will be very important in assessing what the problems are and aren't when it's done," he said.