DTV data is called invalid

Broadcast industry leaders finally settled the marathon battle over digital TV transmission technology when they voted to back the current 8-VSB modulation standard Jan. 15. Or did they?

Industry officials in charge of the tests that convinced the industry to stick with the current technology have been snared in a new dispute. Now they're tangling with the UK manufacturer of the equipment used to compare 8-VSB with COFDM, the rival standard used in Europe and Japan.

Broadcast Technology Group Ltd. said its product was misused in the U.S. tests, directly leading to COFDM's poor performance.

"The integrity and validity of the data collected using our pro-ducts ... can be dismissed as being irrelevant at best," wrote Broadcast Technology's Managing Director Nicholas Jennings in a Jan. 22 letter addressed to officials at the National Association of Broadcasters and Maximum Service Television.

The test results, which led the U.S. broadcasting industry to endorse 8-VSB after nearly two years of constant campaigning by Baltimore's Sinclair Broadcasting to switch technologies, showed that COFDM performed worse than the current standard when received via a 30-foot outdoor antenna. Both technologies showed poor performance with small, indoor antennas.

Sinclair bitterly reacted to the tests as soon as the results were announced, but NAB and MSTV officials dismissed the company's criticism as little more than sour grapes. The admonishments from an overseas company with less at stake in the U.S. DTV transition prompted the trade groups to formally defend their actions.

Jennings contends that his product, loaned to NAB for the tests, was never intended to receive over-the-air transmissions. Instead, the device was created to check broadcast signal degradation and connects to transmitters via direct cable connections, although it can get signals over the air. To receive a single channel that way, however, the device, the Digital Terrestrial Transmitter Monitor 2000, should be equipped with special filters to combat interference.

The device "was not designed nor intended to operate in the harsh and open world of an out-of-doors terrestrial receiving environment," Jennings wrote.

Jennings said he was unaware of how the monitor would be used when U.S. industry executives asked to borrow four of the units. "We're not trying to get into the politics of this," Jennings told BROADCASTING & CABLE, "We're just defending our product. The poor test results reflect on the performance of our equipment and we felt it was necessary to point out that it was designed for a particular purpose. [Channel] selectivity was not a focus."

But U.S. executives scoff at any suggestion that Broadcast Technologies' was in the dark about how their equipment was being used, and said the company is being goaded into its attack by Sinclair.

"This is a thinly veiled and desperate attempt by those who are disappointed by the test results to discredit the program," wrote Lynn Claudy and Victor Tawil, the NAB and MSTV technology chiefs, respectively, in a Jan. 26 response to Jennings.

Claudy noted that Sinclair's DTV chief, Mark Aitken, arranged for the Broadcast Technologies equipment loan. "He was the primary contact and he coordinated the selection," Claudy said in an interview. "Broadcast Technologies knew what we wanted the product to do all along and there were no misconceptions about what this test was for."

For his part, Aitken insists he did little more than provide European contacts for obtaining COFDM equipment.

Aitken also said the trade groups reneged on a promise to conduct a study of possible COFDM enhancements, such as whether slowing the data-flow rate from 19.76 Mb/s to 17.56 Mb/s would make the technology better able to resist interference.