25 June 1999

Digital TV pioneers up for UK's biggest engineering prize

The engineers who made possible the leap to digital terrestrial TV now have a 1 in 4 chance of winning the UK's biggest engineering prize, the £50,000 Royal Academy of Engineering MacRobert Award for innovation. The Academy will announce a team from NDS Limited, based at its Chilworth and Stoneham Research and Development centres, as one of the four finalists for the award on 24 June 1999. For Dr Mike Windram FREng, Arthur Mason OBE, Wilfrid Harding, Warren Hobson and Jeff Gledhill, it comes after a ten-year battle to make the technology work commercially. They have made room in the supposedly full UK broadcasting spectrum for up to 60 new TV channels.

The digital TV adventure, with its set-top boxes and promises of interactive TV, owes its existence to an inspiration by Arthur Mason, now NDS Research Manager. Ten years ago, he was head of an Independent Broadcasting Authority team called SPECTRE, addressing the challenge to improve existing analogue TV signals. The team believed that they could find space between the existing analogue broadcast signals by overlaying them with broad, low-power digital signals. "I remember us staring at the colour-coded map of the broadcasting regions trying to figure out how to do it so we wouldn't interfere with the existing network," says Mason. "The UHF analogue signal is so sensitive that you cannot repeat the frequency closer than two broadcast regions apart - this meant the UK had to have nine separate frequencies, ie. 4.5 channels. We knew we could re-transmit an existing frequency at low power (1/100 - 1/1000 strength) from a site much closer to the original high-power signal. We suddenly realised how we could 'cut and paste' the lattice of transmitter regions so the low-power transmissions wouldn't affect the 50 high-power and 1000 relay stations."

Britain is such an odd shape that it actually took years of effort to plan out the new transmission frequency map so that no-one would get interference. They not only had to worry about interference to British TV - transmitters on the south coast could also have interfered with TV channels in France and Benelux.

Mason caused uproar when he presented SPECTRE's ideas on digital TV at the 1990 International Broadcasting Convention. The broadcasting legislation was based on a maximum of four channels plus a fifth with part coverage (ie. the one that became Channel 5). "Many people thought we were mad to try to do this," says Dr Mike Windram, Senior Vice President of NDS. "At the time, the ITV licences were being offered for rebid, Channel 5 was under consideration, and there was a huge battle for air space on the UHF band between mobile phone and TV suppliers. The mobile industry said that TV should be routed via cable and satellite to free up the radio space. Ironically, digital TV created more space for everyone."

The main reason digital terrestrial broadcasting now works is the advance in technology making it possible to create and use a robust signal of 2000 carriers of 10,000 bps (bits per second) in one 20 Mbps multiplex carrying six channels. Video/audio compression is necessary to get down to the 3-4 Mbps necessary - compression ditches over 95 per cent of the signal, leaving the essential components to maintain the illusion of a picture.

"In ten years' time, analogue TV will be dead," says Mike Windram. The transmitters will be switched off, allowing comprehensive coverage of the whole country on digital channels. "The UK is leading the world - we were the first to launch digital TV in 1998. NDS has already sold over £35 million worth of digital broadcasting equipment - we have been quick to turn our research achievements into commercial success."

ends

Notes for editors

1. The Royal Academy of Engineering MacRobert Award is Britain's premier prize for engineering. It is given annually for outstanding innovation of benefit to the community. First presented in 1969, the award consists of a gold medal and £50,000 prize.
   
2. The outright winner of the 1999 Award will be announced in November 1999.
   
3. The three other finalists are British Aerospace Systems & Equipment for the silicon VSG gyroscope, Buro Happold for the Millennium Dome, and Carbospars Ltd for the AeroRig carbon fibre sailing rig.
   
4. The Royal Academy of Engineering aims to pursue, encourage and maintain excellence across the whole field of engineering in order to promote the advancement of the science, art and practice of engineering for the benefit of the public. The Academy comprises the UK's most eminent engineers and is able to use their combined wealth of knowledge and experience to meet its objectives.

For more information please contact:

Jane Sutton at the Royal Academy of Engineering
tel: 020 7227 0536 (direct), email: jane...@...org.uk

Margot Field at NDS Limited
tel. 020 8476 8158, mobile 0385 313859, email: mfield@ndsuk.com

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