Fox Cooks Up Fix for DTV

Claims new chipset developed with Philips and an Australian university solves indoor reception problem

Fox, Philips Research and Australian National University have created a new digital TV reception chipset that they say solves many of the multipath reception problems that have plagued indoor reception of DTV signals—and also demonstrates the viability of the 8-VSB transmission standard.

"We've proven that 8-VSB is perfectly usable for commercial deployment," said Andrew G. Setos, Fox Group president of engineering. "That puts to bed anyone who says we needed COFDM which has its own problems." COFDM is an alternative DTV transmission technology.

1,100 cities studied

The chipset is a result of a multiyear study of reception data from 1,100 locations in New York, Los Angeles, Chicago and Atlanta. The data was taken to a lab where engineers from Philips Research and the university attempted to tweak the chipset algorithms to improve reception. The results of the study are published in the most recent issue of the IEEE Transactions on Broadcasting journal. According to the study, the chipset can receive indoor signals in 85 percent of the situations.

"The way Fox gets value was to make sure that no one consumer electronics company could monopolize this and so, therefore, only one brand of set would work," said Setos. "By putting the technology into the hands of Philips Semiconductor, any set maker can theoretically buy the chipset."

Setos said the cost of the chipset that will be available from Philips Semiconductor should be in line with the cost of other chipsets because the solution is in the elegance of the algorithms, not the raw silicon.

"Now it's practical to make a good receiver so it's up to the marketplace," he said. "It's not that 8-VSB is a flawed standard or that you can't make a good receiver. Now it's simply go ahead and do it."

NAB top engineer impressed

Setos said that some indoor reception areas, like basements or certain areas in an apartment building, will still be subject to reception problems when using an indoor antenna.

Improving DTV indoor reception has been a major quest for not only chip manufacturers, but also organizations like the NAB, MSTV and the ATSC. And early word on a potential broadcast lab is that it too will focus much of its energies on indoor DTV reception.

Arthur Allison, NAB senior engineer of science and technology, hasn't had a chance to look through the study but the large sample size and the length of time Fox took to verify the data gives him confidence in the results.

The work from Fox and Philips follows that of others like Linx and ATI. "As time goes on, the receiver chips are getting better, and this prototype from Fox—like the Linx receiver—convinces me that the strength of signal needed for reception in an indoor environment is going to steadily decrease as technology improves," Allison said.

A representative from a leading electronics manufacturer said that the development is important because chipset design is a competitive element in DTV set manufacturing.

"More competition for design is better because it helps everyone advance the ball a little further," he said. He added that the most important aspect of the report is that it validates 8-VSB and could be useful in silencing any lingering critics of the modulation standard.

Flexible solution

Fox became involved in the reception issue after a Nielsen study showed that up to 40 percent of Fox viewers were watching via an over-the-air signal at some times of the day. "Early on we realized that we were in deep trouble as an industry if we weren't going to determine that the system could work or not and then figure out how it would work properly," Setos said.

Fox then approached various consumer electronics manufacturers. Philips had the capabilities it was looking for, he said.

"Because of this there is no need to shift gears to other transmission systems and no need to reduce the data capacity of the basic transmission system" to make reception more robust, he said. "The flexibility for broadcasters or viewers is still there and with excellent reception characteristics."

Does this mean the DTV receiver market will start moving? "When the marketplace wants to do something it can go very fast," said Setos of when the first chipsets could hit the market. "We've stimulated the marketplace so now we'll see what happens."