Transposer systems for digital terrestrial television

The UK digital terrestrial television (DTT) network has completed its first phase of roll-out, with over 70% of the population now able to receive all six digital multiplexes. Whilst this is an impressive achievement, the current analogue TV network can cover 99.7% of the UK population and digital satellite systems can boast virtually 100% coverage, so DTT still has some way to go. DTT coverage must improve in order to make analogue switch-off a politically acceptable reality and to compete directly with satellite in value-added services, such as shopping or banking. Analogue switch-off is a particularly desirable goal, as it would release a significant amount of valuable spectrum for use by other commercial services (e.g. mobile telephony). This paper addresses the use of transposers, in a manner similar to that of the current analogue TV network, in order to extend coverage cost-effectively to those viewers currently unable to receive all of the digital multiplexes. A number of transposer designs are considered, employing both DSP and high-temperature superconducting (HTS) techniques, and results presented on some of the technologies employed.