feature green broadcasting

Feature sponsored by Harris

Terrestrial transmission of television and radio is set to stay with us for a long time to come. Satellite radio has not proved an attractive proposition, and the EBU’s recent statements on standardisation for hybrid broadcast/broadband services have made terrestrial television technologies more attractive for the future. Thomson’s Nicolas Dallery reports.

ransmitters are inherently inefficient in the way they use power. Traditionally operating at efficiency rates of less than 20%, the digital transmitter network in a European country will consume several tens of gigawatt hours of power a year, at a cost of several million Euros and resulting in tens of tonnes of CO2 emissions. Improving efficiency is clearly imperative. New technologies in the market are having an impact on these figures.

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For instance, moving from broadcast band analogue to DRM for long- distance radio services can deliver good quality with a reduction in power consumption of up to 40%. At Thomson, we have developed a number of techniques of our own, or optimised existing ones, to build solid- state transmitters for all applications from very low frequencies to S-band, for radio and television. One of the first examples was the use of pulse step modulation (PSM) in our high power short wave radio transmitters which, since the early 80s, have boosted energy efficiency. The progressive introduction of other smart designs, including reducing carrier power when transmitting silence, or digital signal processing techniques, today pushes the efficiency limits for radio transmitters towards 90%. In the same time period, the IOT (inductive output tube) technology for

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GreenPower for

efficient transmission

Nicolas Dallery. The second

generation of Elite 1000 digital TV transmitters - the GreenPower series.

TV transmitters, actually invented in 1938 as a means of improving transmitter efficiency, benefited from new manufacturing techniques that have allowed the full benefits of IOTs to be realised. Thomson remains the market leader in MSDC-high-power IOT transmitters - the DCX Paragon MSDC-IOT transmitter provides plant efficiencies approaching 60%! But the most exciting challenges today are with solid-state TV transmitters where huge improvements are foreseen in the coming years to move from the current 20% poor figure for power efficiency to a 40% target and thus divide by two the power consumption of digital television networks. At Thomson we are carrying out considerable research into new technologies in the field of power amplification and digital signal processing.

Today, the outcome is a second generation of Elite 1000 digital TV transmitters - the GreenPower series - where the focus has been on the environmental aspects that will drive the new technologies for the next decade. Once again, Thomson transmitters are setting the pace of innovation by introducing new transistors with improved efficiency, RoHS manufacturing, and enhanced power density to minimise floor space requirements.

Our 40% target for energy

efficiency has not yet been reached, but our R&D teams are still working towards this goal with features such as PAPR ACE mode to reduce the peak to average power ratio, and thereby control energy consumption without any impact on the quality of service. Further, Thomson continues to take an active role in European advanced research programmes and

standardisation bodies to develop the next generation of signal processing techniques and amplification components, with the aim of achieving even greater power efficiencies in the future.

Alongside the development of the electronics, work is also underway to ensure continuing innovation in antenna design. Ensuring that coverage patterns are tightly controlled and accurately focussed minimises RF losses and therefore energy consumption.

It is also worth remembering that the same technologies developed for digital broadcast transmitters are also used as controllable high-power sources in scientific and medical applications as diverse as nuclear fusion research and advanced cancer therapies. Continuing to advance the science of radio and television terrestrial transmission will make a significant reduction in the operating expenditures of broadcasters and their carbon footprints, but it will also have wider benefits throughout society. Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48