THE drive to convert the US to digital television is grinding to a halt. The
government is being warned that its plan to persuade households to abandon
analogue television is 鈥渋n disarray and on the verge of collapsing鈥�. The system
the US has chosen to broadcast digital TV gives poor reception鈥攅specially
in urban areas. As a result, fewer than 5000 digital TV receivers, at $10
000 a time, have been bought since services launched a year ago.
Strategy Analytics of Boston, the firm which issued the warning, has a good
track record on consumer technologies. It predicted correctly that the Divx
pay-as-you-play DVD system would flop, as well as the CD Interactive multimedia
system from Philips. In its latest report, SA predicts that 鈥渓ess than 5 per
cent of US households will be watching digital television by 2005鈥�. The
government wants a complete switch to digital TV by 2006.
Both Europe and the US government want viewers to go digital so that they can
sell off the freed-up analogue frequencies for new mobile services. But they
have adopted radically different approaches.
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Ten years ago, the European Commission tried to convert European viewers from
625-line analogue TV to an analogue 1250-line high-definition TV system. But
viewers did not want to buy expensive new HDTV sets. Since then, Europe鈥檚
Digital Video Broadcasting (DVB) group has developed a digital TV standard based
on 625-line pictures, at least initially.
DVB lets viewers simply plug in a new set-top box between a terrestrial
antenna and an existing analogue TV set. If anyone wants to, they will be able
to boost picture resolution with special widescreen sets later. DVB is
transmitted using a system called COFDM, which rejects unwanted signal
reflections鈥攖he annoying double images TV viewers call 鈥済hosts鈥�. And the
DVB signals are sufficiently robust to work with a set-top aerial.
In the US, the Federal Communications Commission and its Advanced Television
Standards Committee decided to adopt a digital HDTV system using a transmission
system called Vestigial Side Band (VSB), a simpler technique than COFDM and
similar to that used for North America鈥檚 525-line analogue TV. But the system
copes poorly with echo signals: the picture disappears completely with digital
TV, rather than just ghosting, especially in urban areas where buildings cause
echoes.
Viewers don鈥檛 want to buy new receivers that provide poor digital pictures
and which won鈥檛 work with set-top aerials. TV makers are trying to improve
reception with circuitry that cancels out ghosts, but opponents are
sceptical.
Led by the Baltimore-based TV network Sinclair Broadcasting, more than a
third of all US commercial broadcasters are now asking the FCC for permission to
use COFDM transmission instead of VSB. Nat Ostroff, Sinclair鈥檚 technology chief
described VSB as 鈥渁 rotten fish鈥�.
David Mercer of SA says: 鈥淚t鈥檚 decision time for the FCC. The US needs a
system that works to regain the confidence of the industry as well as
肠辞苍蝉耻尘别谤蝉.鈥�