Digital Broadcast: reducing transmission network energy cost and environmental impact
The worldwide introduction of digital terrestrial TV systems will lead to significant numbers of new transmitters being installed over the next few years. With the recent rise in energy prices, and increasing concerns over environmental impact, it is important that these new transmitters are as energy-efficient as possible.
Operational costs have always been a key issue for broadcasters, and a substantial part of these costs is due to the electricity required to run the transmitters (typically accounting for over 75% of total electricity usage).
Aside from the cost argument for increased transmitter efficiency, there is also a strong desire from the broadcasters to improve their environmental or 'green' credentials and to be seen to be responsible in their use of energy.
Current digital TV transmitters are very power-inefficient due to the use of linear RF power amplifiers (PAs), which typically account for half of the total power used by a transmitter.
Application of Nujira Technology
The diagram below shows how envelope tracking is applied to a typical multi-element UHF transmitter using a number of PAs connected in parallel to achieve the required output power. Each PA is equipped with a Nujira HAT™ Power Modulator which dynamically varies the supply voltage in line with the signal envelope, all driven in parallel from the envelope signal generated by the exciter.
Benefits
Nujira’s technology has the potential to reduce transmitter energy consumption (and hence CO2 emissions) by 50%, increasing network profitability and helping broadcasters’ ‘green’ credentials.
In addition, Nujira’s technology enables lower maintenance costs and greater reliability through reduced heat dissipation, and allows the design of smaller and cheaper transmitters, leading to lower site costs. Also, the lower power consumption reduces the backup power requirements, further reducing CAPEX and OPEX costs. Finally, Nujira's HAT™ technology supports full UHF (470 - 860 MHz) band coverage using a single PA.
For more information on the OPEX and environmental benefits arising from the use of Nujira's technology, click on the links in the adjoining box.
Product Status
Nujira is currently shipping pre-production Power Modulators to support trials with a number of leading transmitter vendors. First announcements of volume commitments are expected H2 2008, with volume shipments beginning in 2009.