DVB-Terrestrial Demo Fuels DTV Fight At NAB

By Junko Yoshida, EE Times

12-Apr-00

Heated debates and partisan attacks over digital TV terrestrial demodulation schemes characterized the National Association of Broadcasters (NAB) convention on Monday, April 10, 2000, pitting the 8-VSB scheme selected for use in the United States against COFDM, which had been chosen as Europe's digital video broadcast-terrestrial (DVB-T) standard. Critics of the 8-VSB standard are insisting that COFDM be added to the US standard.DVB supporters staged special demonstrations for the US broadcasting audience at the NAB 2000 conference to prove that the DVB-T standard is perfectly capable of delivering both HDTV and standard-definition TV (SDTV) mobile reception using the 6MHz of spectrum assigned to that purpose for digital TV broadcasts in the United States. Nat Ostroff, Vice President of New Technology at Sinclair Broadcast Group Inc. (Hunt Valley, Maryland), a COFDM proponent, said at the DVB press conference Monday, ""The [DVB] demo today, for us, is a milestone. It shows what can be done now in HDTV and SDTV delivery with a simple indoor antenna. ""We - Sinclair and 400 independent stations - believe the time for promises is over,"" Ostroff said. ""The time for performance has arrived. Vague schedules for improvement is no longer acceptable."" On The DefensiveThe DVB demo clearly put ATSC backers on edge and on the defensive at NAB 2000. Consumer electronics manufacturers held their own press briefing at the conference in an attempt to defend their position, chaired by Richard Wiley, the former Chairman of the Federal Communications Commission and former chairman of the Advanced Television Systems Committee (ATSC), which selected the 8-VSB modulation scheme as the US standard. Asked if the current US digital TV standard can deliver HDTV and mobile services like those demonstrated by the DVB group, Robert Perry, Director of Marketing for Mitsubishi Digital Electronics America Inc. (Irvine, Calif.), said, ""That is not the intent"" of the ATSC standard."" He added, ""The advanced mobile/portable digital TV service is just a sideshow."" Consumer electronics manufacturers at the briefing reiterated their position that the ATSC chose 8-VSB because of its maximum data rate and the maximum coverage that can be implemented in a non-interfering way. Despite a series of attacks on 8-VSB over the last several months, commitments to help improve digital TV reception in the United States were apparent in a joint initiative announced Monday by Royal Philips Electronics and Fox Television. The companies agreed to research ways of improving digital TV reception using the current 8-VSB standard. Cornell University and the Australian National University are also partners in the initiative. Under the agreement, Fox will provide extensive data for channel characterization and for laboratory and field analysis, gleaned from the 22 local television stations it owns and operates. Philips Research, meanwhile, will be responsible for contributing algorithmic and architectural modifications to improve the performance of 8-VSB receivers. That data will be sent to Philips Semiconductors, which will use it to design a newer-generation 8-VSB demodulation chip, according to Philips. Cornell and Australian National will address channel characterization and receiver improvement aspects of the project, Philips said. As broadcasters begin to look for diversified digital services they will be able to provide in addition to HDTV broadcasts, it is unclear if the 8-VSB vs. COFDM debate will fizzle as ""another bump on the road,"" according to Wiley, a senior partner with Wiley, Rein & Fielding (Washington, D.C.). Two Services, One TransmissionUsing the DVB-T hierarchical modulation scheme, HDTV and SDTV service was transmitted using the facilities of KVWB-DT29 located in Black Mountain, Nevada, 17 miles from NAB 2000 at the Las Vegas Convention Center. The signals were sent from a single transmission tower using 200 kilowatts of power. No repeaters were used in the signal transmission. Using an indoor antenna, the 720-progressive HDTV images were received by an NDS-designed set-top and shown on Pioneer's plasma display, while 480-interlaced SDTV pictures were displayed on a Nokia portable flat-panel display with a small, integrated antenna and a COFDM demodulator. Nokia's portable TV is designed to receive SDTV and to support short messaging services, e-mail and Web-browsing capabilities. Peter MacAvock, DVB Executive Director, said the DVB-T hierarchical modulation supports ""two different, independent services that can be transmitted to two independent receiver population simultaneously on a 6MHz, 7MHz or 8MHz spectrum."" Pointing out the continuing progress of DVB, MacAvock said, ""The key message here is that equipment using off-the-shelf DVB-T components can offer a new generation of mobile, telecom and Internet services, preparing broadcasters well into the 21st century."" At the DVB briefing, Sinclair's Ostroff held up a wireless, portable Nokia display at a podium, turned its switch, and showed off its clear DVB-T reception. ""This is the level of performance that we have now established as a benchmark and that we want,"" he declared. That level of performance is not available in the current ATSC standard, and ""may never become available in our life time,"" he said. Quoting an estimate by Thomcast, a transmitter company, Ostroff said that a TV station could switch from VSB to COFDM by using a plug-in-card that costs ""about $7,500."" That is not a huge investment, he said. Slower ProgressBut if such a switch happens, officials with the Consumer Electronics Association (CEA) argued, the already slow transition to DTV in the United States will be delayed even further. According to CEA's estimate, 200,000 DTV products have been sold since the fall of 1998. Only 17 percent of such products come with a tuner and VSB demodulation chip that make them capable of receiving terrestrial DTV signals. If current plans stay on course, the CEA projects 30 percent DTV penetration of the US market by 2006. If more original DTV content comes online for broadcast by networks, the industry group said that 50 percent penetration could be achieved in the same time frame. But if the ATSC standard is switched from 8-VSB to COFDM, or changed to add COFDM, the revision will drive DTV penetration in the US market down to 15 percent by 2006, CEA said.