Summary

Sinclair Broadcast Group's Baltimore tests revealed that the US 8VSB digital terrestrial transmission system consistently failed to produce pictures on indoor set-top antennas, while Europe's COFDM system performed robustly. The findings raised the possibility of an unprecedented reversal in US digital TV policy, with the FCC and ATSC under pressure to reconsider the mandated standard.

Source document circa 1998 preserved as-is

 

From Europe

TESTS REVEAL FLAWS IN US HDTV SYSTEM

Recent tests of the US digital terrestrial high definition TV system have shown up serious reception problems that could mean the US abandoning the system that began rolling out last autumn. Instead, it could adopt a transmission scheme much closer to the European model. The Sinclair Broadcast Group, which owns 60 TV stations across the US, has been comparing the US and European transmission systems in Baltimore - in particular testing how well each is received by set top antennae. The European COFDM modulation system has proved to offer very robust reception, while the US 8VSB modulation system has in many cases failed completely to generate pictures on indoor antennas. The US system was originally tested and passed for use with external antennas, and it apparently works well in rural areas. It is also claimed to be a cheaper system to implement than the European DVB-T system. However, those broadcasters which have substantial interests in serving city communities want reassurance that the US system can be made to work with set top antennae.

"We'll be investing millions of dollars in digital TV - and if it doesn't work it's completely unacceptable - and it shouldn't be allowed to to be sold into the US marketplace" Sinclair president David Smith told Broadcast. A change of system would mean an unprecedented reversal in government policy and a severe embarrassment for the US TV regulatory authorities.

However, the response so far of the US Federal Communication Commission, which mandated the US standard, and the Advanced TV Standards Committee, which recommended the technology, is to wait and see whether receiver manufacturers can solve the reception problems in the next generation of DTV receivers. However Smith suggests this is not likely to happen. "We've talked to the receiver manufacturers and we're not led to believe anyone has a solution to this problem - we asked them to give us their best receivers - and none of them could decode continuously, successfully, using the US system under normal consumer conditions" he says.

The FCC and ATSC are also waiting to see the results of tests later this month in Brazil, which will be choosing between the European and US systems for the country's planned digital terrestial TV service. So far, the DVB system has been selected by the great majority of countries planning digital services. Japan is to use its own version of the European system and Australia also chose DVB-T after exhaustive tests. Most recently Singapore chose the European system for its plans for two terrestial DTV channels - one of which will transmit to mobile receivers in the city state's extensive commuter network of buses and trains - something else the US 8VSB system cannot do.

Copyright - Nick Radlo