DTT services began in the UK on 15 November 1998, with six multiplexes offering a mix of free-to-air, primary and premium channels. Four of these multiplexes should reach 90% of the UK population by the end of 1999 while the remaining two will reach around 70% of UK households, because of restrictions.

This article explains the fundamental differences between UK DTT and previous DVB implementations, and argues in favour of open standards and “horizontal” DTT platforms as the model for the future.

The Eureka-147 terrestrial DAB system has been shown to be also suitable for satellite broadcasting at an international level. However, a method is needed to uplink the programme datastreams from, perhaps, several widely differing locations – to form a single DAB multiplex at the satellite for transmission to the consumer.

This article describes the possibility of using a conventional geostationary satellite, in conjunction with the TDM technique, to achieve multi-uplink access to the satellite.

The HuMIDAB project was born out of a belief – among EBU and WorldDAB members – that the Eureka-147 DAB standard would open so many new opportunities for receiver designs that the digital radios of the future could not just replicate the analogue radios of today. Future digital radio services would provide a package, including audio programmes, associated services – such as programme-related data – and, at a later stage, multimedia capability in the form of pictures, perhaps even moving ones!

Both the broadcasters and the receiver designers would have to rethink the requirements of digital radios. They would have to work together to formulate an intrinsic understanding of the other’s role, to allow the design of new digital radios with many enhanced features.

This article reports on the work carried out within the project, which had only a one-year time frame.

In order to evaluate the operational and technical feasibility of using standardized telecom network techniques for broadcasting applications over LANs and WANs, the IRT has set up an internal ATM-based high-speed transport network. It has also carried out tests on ATM WANs and was heavily involved in the planning and evaluation of the ARD HYBNET ® field-trial network, and in other trials and demonstrations which are described here.

Based on these IRT tests, the author provides basic evidence as well as some general results and conclusions in favour of using ATM in broadcast networks which consist of both LANs and WANs.

Coded Orthogonal Frequency Division Multiplexing (COFDM) is a form of modulation which is particularly well-suited to the needs of the terrestrial broadcasting channel. COFDM can cope with high levels of multipath propagation, with a wide spread of delays between the received signals. This leads to the concept of single-frequency networks in which many transmitters send the same signal on the same frequency, generating “artificial multipath”. COFDM also copes well with co-channel narrowband interference, as may be caused by the carriers of existing analogue services.

COFDM has therefore been chosen for two recent new standards for broadcasting – DAB and DVB-T, both of which have been optimized for their respective applications and have options to suit particular needs.

The special performance of COFDM in respect of multipath and interference is only achieved by a careful choice of parameters and with attention to detail in the way in which the forward error-correction coding is applied.