The new chip will be unveiled at this week's (April 7-11) National Association of Broadcasters conference in Las Vegas.

With its new Theater 310 chip, ATI said it hopes to set a "new benchmark for digital cable-ready DTV products, both in its integration and performance," said Mike Gittings, ATI's director of digital television marketing.

Chip vendors are banking on growing interest among OEMs in integrated digital cable/digital terrestrial/analog TV receiver ICs after following a DTV agreement reached late last year between the cable and consumer electronics industries. The deal would allow TV manufacturers to launch long-awaited digital cable-ready DTV sets requiring no cable set tops.

The Theater 310 chip demodulates and decodes vestigial sideband (VSB) for the U.S. terrestrial digital TV broadcasts and 64 and 256 quadrature amplitude modulation (QAM) for digital cable. It also handles analog NTSC (National Television Standards Committee) video signal demodulation and analog BTSC (Broadcast Television Systems Committee) audio signal modulation and decoding.

Although digital TV makers are already familiar with integrated VSB/QAM receiver chips through use of ATI's previous generation chip or similar offerings, until now they have not seen a receiver IC that "has pulled together BTSC and NTSC front-end audio and video receivers and IF components all into a single-chip VSB/QAM receiver," Gittings said.

The Theater 310 chip effectively eliminates the need for three SAW filters and one intermediate frequency (IF) amplifier, he added.

Higher integration is only half the story for the new chip, according to Gittings. He said "there is still some room left for improvements in VSB reception," adding that several new techniques are incorporated in the Theater 310 to boost the VSB performance.

For one, the equalizer span used in the Theater 310 was extended from 53.5 to 88 microseconds. "We make a very efficient use of equalizer tap, so that 88 microsecond span is a true-span measurement," Gittings said. ATI's engineering team also developed a newly enhanced semi-blind and blind equalization algorithm for the chip.

Gittings said the chip may be the first capable of handling Rayleigh fade, a condition caused by multipath interference. When the waves of multipath signals are out of phase, reduction in signal strength can occur. Signal strength can fluctuate, thus causing a momentary, but periodic degradation in quality. Traditional equalizers do not handle such a fading, Gittings said.

ATI engineers also focused on slow channel changes that could occur as consumers hop from one channel to another, and between VSB, QAM and NTSC signals. An 8-bit micro-controller and dedicated hardware resources integrated on the Theater 310 aim to make faster channel change possible — as fast as 50 milliseconds, Gittings said.

The Theater 310, which starts sampling in the third quarter, will be manufactured by using Taiwan Semiconductor Manufacturing Corp.'s 0.15-micron process. ATI would not disclose the price of the new receiver IC, saying only that "the price for DTV products depends on the volume and other conditions."

DTV politics

Indeed, politics evolving around the U.S. digital TV could still affect all parties involved in the DTV food chain, ranging from chip companies to TV set manufacturers.

While the Federal Communications Commission is being urged to quickly adopt the proposed digital cable- ready DTV specification, Hollywood studios remain a wild card, and their support for the proposal remains unclear. So-called "encoding rules" that limit use of copy protection technology remains an issue for some content owners. That debate continues at the FCC.

Complicating matters further, the consumer electronics and cable industries remains at odds over a certification process for digital cable-ready DTV sets. Although it has been four months since the two industries reached the so-called "plug-and-play" agreement for digital cable-ready DTV, no decisions have been made on what aspects of plug-and-play DTV sets that need to be tested by CableLabs, the cable industry's technical arm, and what should be left to TV set manufacturers for self-certification.