This article has been reproduced from ITU News July 1997 pp 27-29.

Television broadcasting given a major boost with the adoption of two landmark standards

The international Telecommunication Union has defined two major standards that might revive the television industry for years to come.

It has agreed on a new global standard for digital terrestrial television broadcasting (DTTB) which will result in end-to-end digital television with highdefinition quality, and will unify television broadcasting systems worldwide. It has also unanimously agreed on the convergence towards a single high definition television (HDTV) production standard based on the high definition common image format (HD-CIF).

Global standard for DTTB

This unprecedented move in the field of television broadcasting gives the go-ahead for equipment manufacturers to start delivering television sets anywhere in the world. It will certainly provide economies of scale never available before as well as worldwide portability for consumers and vendors.

The standard describes a revolutionary technique which will provide almost twice the resolution of standard colour television systems, In addition, a totally new colour system will prevent "artefacts" (colour and image distortions) which are sometimes experienced with today's systems.

The resolution supported by the new system is equal to or better than that of a standard 35 mm film. In addition, the system can support 16-channel sound of the quality normally expected from a home stereo sound system. Besides offering improved quality, the number of channels may mean that broadcasters can transmit a programme with several different language tracks.

Work on a new system for digital television was prompted by requests, notably from the World Broadcasting Unions (WBU), to develop a new standard that could be used worldwide.

"Broadcasters around the world have consistently supported a global approach to the development of new systems and this is largely because they are driven not only by their economic objectives but also by a sense of responsibility to their audiences. No other industry places as much value on free and universal availability of its services. Common standards provide economies of scale and hence minimize the costs of consumer technology - a necessary prerequisite for the availability of new service products to the consumers", said 0.P. Khushu, Chairman of the Inter-Union Technical Committee of the WBU. He also added that the ITU-R (Radiocommunication Sector) was to be congratulated for having worked towards this objective in the case of DTTB.

At present, there are more than 40 different television systems in existence, including the well known PAL, SECAM and NTSC systems. These systems are incompatible with one another, which means that equipment and videotapes designed for one type of system will not operate in a country using a different broadcasting standard. This situation has led to increased production costs of television sets and related peripherals such as videotape recorders and added costs for television networks in the exchange of programmes.

The new ITU "umbrella" Recommendation succeeds in unifying two "competing" standards the United States-favoured ATSC proposal, and the European-developed DVB proposal. The two systems will, under the Recommendation, form a single compatible system that can be implemented on a global basis within the practical physical limitations of the current channel assignment environment. "We would have liked to see the Recommendation specify a unique transmission format, but we do not live in a perfect world!" Mr Khushu declared.

When developing the set of Recommendations, ITU-R Study Group 11 (Broadcasting service (television)) had as its goal the construction of a digital architecture that could accommodate both high-definition television and conventional television services in the terrestrial broadcasting environment, while at the same time being interoperable with cable delivery, satellite broadcasting and recording media.

In addition, the new digital system will support multi-programme transmission in existing channels via digital signal compression technology. Such compression will increase the number of available channels, improve performance, and at the same time improve the utilization of the radio-frequency spectrum, an increasingly rare resource. Such digitally compressed signals can be accompanied by digital high quality sound, coded conditional access information, or ancillary data channels.

"An important feature of the standard is that it has evolved from voluntary agreements among all parties which have a stake in the digital future, including the broadcasting, equipment manufacturing and computer industries, and this will become increasingly significant as we move into the age of multimedia and information highways", Mr Khushu stated.

The digital television market is estimated to be worth some hundreds of billions of dollars over the next ten years or so. Initiatives have been made in the United Kingdom and Australia but, with the market opportunities which a single worldwide standard will provide, a large number of broadcasters are expected to begin transmitting in 1998 either Digital Video System A or Digital Video System B.

"This landmark decision is putting an end to decades of fragmention in the television market, which will be of benefit to consumers worldwide", declared ITU Secretary-General, Pekka Tarjanne. "I pay tribute to Study Group 11 Chairman Mark Krivocheev for his remarkable work and achievement in bridging the differences in this field", he added.

Analogue transmissions will eventually be phased out (a ten-year time-frame is proposed in the United States, while a longer time-frame is expected for Europe). It is envisaged that, as transmissions change from analogue to digital, analogue televisions may be fitted with set-top boxes to enable them to decode and process the digital signal. This will prolong set-life, and give the equipment market time to mature before consumers are required to replace their equipment. Chip manufacturers have already announced that they are ready to start mass production of the chips required by the decoders to be integrated in the new television sets.

There are currently 1288 million television sets worldwide which will eventually be replaced, representing a huge market (Figure 1)

HDTV production standard

Study Group 11 also agreed on a new version of its Recommendation for HDTV programme production (Recommendation 709). The new version was agreed unanimously by all administrations and organizations who where in Geneva in April 1997 for the meetings of Working Party 11A and Study Group 11 . It represents a new chapter in the worldwide harmonization of HDTV. Many believe it will kick-start the age of HDTV, so long heralded but slow in coming until now.

The previous Recommendation offered two specifications with equal weight and included a note of reservation by the Unite States. The new version includes a new format, called the HD-CIF format, which is cited as the preferred format for new implementations. The United States has also removed its reservation.

The road to worldwide use of a unique type of equipment for HDTV programme production is now open.

The HD-CIF format is characterized by using a single matrix of samples (1080 by 1920), irrespective of the field and frame rate used. This matrix thus becomes a unique format for image capture for high-definition pictures for any application. In future, Working Party 11A and Study Group 11 will study the use of this HD-CIF format as a building block for super high definition television systems.

Mr Krivocheev explained that: "This is a remarkable achievement by Working Party 11A. It represents the culmination of over fifteen years of discussion on high definition television production standards. This agreement shows the unique effectiveness of the ITU-R as a worldwide forum for standards in broadcasting."

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