Matt Miller, president and chief executive officer, said that with the company's new chip, a 30-foot specialized outdoor antenna for DTV will soon be a thing of the past, allowing consumers to receive DTV signals with an indoor, $2.99 UHF bow-tie antenna.

The chip's equalizer zeroes in on one of the plagues of today's terrestrial digital-TV reception -- static and dynamic multipath interference.

Back in the late '80s when nobody thought it was possible, Miller, as vice president of technology at General Instrument Corp. encouraged his engineers to design an all-digital television. Today, Miller is out to prove the industry wrong again.

NxtWave Communications Inc. has focused on developing a high-performance DTV demodulation chip. The chip debuts at a time when vestigial sideband (VSB) technology is under sharp attack from some broadcasters because of its susceptibility to multipath interference.

Armed with the company's new demodulation chip, Miller said, "I think we can safely say there is nothing wrong with today's U.S. HDTV standard using VSB." Although he declined to speculate on motives behind broadcasters such as Sinclair Broadcast Group -- which is pushing its own agenda to petition the Federal Communications Commission to allow coded orthogonal frequency-division multiplexing (COFDM) to be a part of the DTV transmission standard -- Miller responded, "Let's get on with it and go build the industry."

NxtWave's NXT2000, sampling today and due for volume production in the fourth quarter, will come with a number of unique features -- in terms of higher integration and performance -- not available in its competitors' VSB chips.

First, the new ASIC is a multimode VSB/QAM receiver IC. It decodes 8 VSB terrestrial and cable signals such as the Docsis-compliant 64/256 QAM. Although its main market is terrestrial DTV receivers which must demodulate VSB signals, having a QAM demodulation capability inside the chip prepares a DTV receiver to become "digital cable-ready," required in the future. In the long run, consumer electronics OEMs will develop DTVs to receive not only VSB-based terrestrial DTV programs but QAM-based digital cable. "Our chip won't be obsolete when that happens," Miller said. "With our VSB chip, QAM capability comes for free."

Also integrated on the chip are a forward error correction as well as a direct IF sampling analog-to-digital converter. No other VSB demodulation chips on the market have gone so far as to incorporate an A/D converter.

NXT2000 stakes its biggest claim-to-fame, however, on its equalizer. With a goal to cancel transmission-channel impairments such as multipath, phase noise, adjacent or co-channel NTSC interference and impulse noise, NXT2000 was designed to speed both DTV signal acquisition and equalization. Incorporated in the equalizer's fundamental architecture were two key techniques: "blind equalization" and "sparse equalization."

Most VSB demodulation chips today use a training sequence that comes with an MPEG stream to equalize. The training sequence essentially allows a chip to do comparisons and figure out math changes between original VSB signals and those signals that were damaged by foliage, buildings or other sources of interference.

NxtWave engineers, however, say they have found a way to equalize without such a training sequence. Applying a technique called "blind equalization," originally developed for military applications, NXT2000 equalizes VSB radio signals symbol by symbol, Miller said.

NXT2000 also uses a technique called "sparse equalization," making a sharp contrast to "a full-equalizer design" in a competing VSB chip jointly developed by the Motorola and Sarnoff corporations recently. The goal of the two competing chips, however, remains the same: to improve DTV reception performance by resolving dynamic and long-delay static multipath problems.

Resorting to the brute force of an equalizer, Motorola's MCT2100 incorporates enough equalizer taps to span the spectrum, so there will be no gaps. In contrast, NxtWave engineers came up with a new algorithm that allows an equalizer to dynamically allocate taps where they are needed. Meanwhile, its equalizer range extends from 4.5 microseconds to 44.5 microseconds to ensure reliable signal recovery in the harshest multipath environment.

"The sparse equalization essentially allows our chip to cost less," Miller said. While Motorola has turned to its cutting-edge 0.18-micron process to make its complex full-equalizer design possible, NxtWave will depend on STMicroelectronics' 0.25-micron CMOS process to fab its chip.

Another feature of NXT2000, which has never been made available by other VSB chips but may do a huge favor for DTV-receiver set manufacturers, is a built-in signal-quality indicator. The chip can actually indicate the strength of DTV signal reception, showing it to a TV monitor like a volume-control bar, to ease antenna alignment. Today, much of the hard work of mounting and aligning a DTV antenna into ideal position is trial-and- error.

The total power consumption of NXT2000 is "less than 2 W," Miller said. The chip is priced at $22 in 10,000-unit quantities.

NxtWave plans to use the current architecture of NXT2000 as a platform to design universal demodulation products for the home, adding to the silicon other demodulation forms such as QPSK.