China to test three formats in massive HDTV trial
By Sunray Liu
EE Times
(09/24/99, 8:06 p.m. EDT)
BEIJING ? As the People's Republic of China kicks off its 50th anniversary
celebration on Oct. 1, broadcasters at state-run television stations are planning a
seminal HDTV trial that will showcase three digital formats, including one developed
by engineers in China.
The National Day pilot, which will televise state ceremonies commemorating the
Communist takeover of China in 1949, is billed as one of the largest HDTV
demonstrations ever and will mark a milestone as the world's largest potential
consumer market feels its way into the digital TV era.
The trial could also go a long way toward determining which global transmission
standard China chooses, upping the stakes for the rival standards being promoted
by U.S. and European manufacturers. Over the longer term, it could spread digital TV
signals throughout China's growing cable system and boost such related industries
as digital TV set-top box manufacturing.
"China Central TV station has established a digital system for HDTV live
broadcasting, including program sources, a digital studio and antenna system," said
Haitao Zhang, deputy minister of the State Administration of Radio, TV and Film.
Speaking at a recent exhibition here sponsored by the administration's Academy of
Broadcasting Science, Zhang said that the Chinese digital TV infrastructure will be
ready for the HDTV demonstration scheduled to being next week.
China is currently evaluating competing digital TV standards from the United States
and Europe. A huge amount of business hinges on its choice of a digital TV
standard, and both sides have been lobbying the Chinese government hard to adopt
their respective schemes.
"We are also developing [an] HDTV standard of our own," Zhang said. The
Academy "has generated the encoder, decoder, modulator and multiplexer for [the
Chinese] HDTV system."
Indeed, the government is hedging its bets on an HDTV standard, seeking to
develop an intellectual-property system, engineering talent and a digital TV industrial
base that will also help its home industries. The days when China's electronics
industry launched local markets by licensing Western technology appear to be over.
Two research teams are developing China's HDTV specs. The HDTV research team
at the Academy of Broadcasting Science is headed by academy vice president
Baichuan Du. The HDTV Technical Expert Executive Group (TEEG), meanwhile, is
backed by the Chinese Ministry of Science and Technology and the State Planning
and Development Committee.
Du said the three HDTV systems developed for the upcoming trial are respectively
based on the U.S. Advanced Television Systems Committee (ATSC) spec, the
European Digital Video Broadcast (DVB) standard and a homegrown format that
accommodates "Chinese realities." He called the ATSC spec's vestigial sideband
(VSB) modulation scheme more effective for fixed receivers but said that the coded
orthogonal frequency-division multiplexing (COFDM) used by the DVB spec offers
advantages for mobile receiving and single-frequency networks.
The Academy's approach was to separate fixed and mobile receiving, dividing the
Chinese 8-MHz HDTV channel into 6- and 2-MHz bands. The larger channel is used
for fixed reception; the smaller one handles data-oriented mobile receiving.
The Academy also tested quadrature amplitude modulation (QAM) in place of VSB
in some instances and concluded that the cable modulation scheme is sufficiently
stable for HDTV broadcasts. "This system [QAM] has two advantages," Du said. "It
can easily integrate [with] cable and satellite systems, and it can be linked to digital
audio broadcasting, another important project."
TEEG, meanwhile, is cooperating with Chinese broadcasters and manufacturers on
development of a second-generation HDTV prototype. Wenjun Zhang, TEEG's
project director, said the prototype system was completed earlier this month. It can
encode 50-Hz or 60-Hz interlaced scanning.
The system will support a combination of HDTV and standard-definition broadcasts
and could be extended to multiplex one HDTV and one or more standard-definition
TV channels. The transmission system can carry both VSB and COFDM modulation
or Chinese versions of both.
The technical group also cooperated with local manufacturers to develop set-tops,
and manufacturing members of TEEG's monitor subgroup have completed a monitor
design and a production plan. The monitor will be able to display an RGB signal
directly. All system interfaces will comply with international standards and will be
able to connect directly to overseas systems.
The trial may not provide a definitive resolution to the standards debate. Sources
here confirmed that broadcast officials overseeing the trial will probably adopt both
research groups' systems.
Cable effort
As HDTV development heats up here, such Chinese manufacturers as the Konka
Group are beginning to export locally manufactured HDTV receivers, and provincial
and city governments are planning a digital cable network that eventually will span
the nation. The heated activity has broadcast authorities here betting that China will
play a high-profile role in the global rollout of HDTV.
"We are the pilot of this industry," an engineer with China's TCL Group said. "Our
products [will include] HDTV sets for ATSC, DVB and the Chinese standards for
ATSC and DVB."
TCL Group donated HDTV receivers to the state television-broadcast authority for
the National Day trial. But industry watchers said the decoders are the key
technology to be tested. If the trial proves successful, the industry can proceed
toward a unified Chinese HDTV standard, sources said.
Proponents of the ATSC and DVB formats are angling for roles in that standard, and
both have made gains here. Europe's DVB Group appears to have the edge thus far,
having twice demonstrated its format to broadcast officials. Deputy minister Zhang
added that "China has adopted the DVB-S for digital satellite broadcasting" based
on the recommendation of the International Telecommunications Union.
But ATSC representatives have also been working closely with Chinese
manufacturers. The group demonstrated its approach at a recent gathering hosted by
the powerful Ministry of Information Industry.
"Three different Chinese television manufacturers have become members of ATSC
recently," ATSC chairman Robert Graves said, and others are considering following
suit. "It doesn't mean they believe ATSC will be the only choice for China. It [means]
they are interested in digital television in ATSC, and they are likely to produce ATSC
products for the world market."
The Chinese manufacturers that have joined the ATSC thus far are Konka, the TCL
Group and the Skyworth Group.
Chip makers LSI Logic Corp. and STMicroelectronics have also stepped up
cooperation with the two HDTV research teams, and Samsung, Philips, Infineon and
Matsushita are said to be targeting the Chinese HDTV market with chip sets of their
own.
Software developers, too, have been active here. Microsoft's CE operating system for
interactive TV, Sun Microsystems' JavaTV APIs and the homegrown Hopen
operating system are all competing for a place in China's emerging digital TV
infrastructure.
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