Digital Audio Broadcasting (DAB)

RTHK is currently conducting the phase four DAB trial, which adopts Europe's Eureka 147 Band III system with the frequency 218.64MHz. Two transmitters have been set up at Mount Gough and Castle Peak respectively, covering areas of city center of Hong Kong, Kowloon and Tuen Mun, Tin Shui Wai and Tung Chung.

The project is now underway and programmes of the FM and AM channels are relayed with high-quality sound effect. To cope with the data transmission, RTHK would set up trial points during the period of International Telecommunication Union (ITU) Telecom World 2006 for the attendants and the public to experience the high sound quality of this new technology.

Comparing with the existing broadcasting technology, DAB has the following advantages:

1. Using single frequency network enhances mobile reception and no fine-tune of frequency is required;
2. Rooted out the problem of interference in AM and FM broadcast;
3. Provides crystal clear sound that is comparable to near CD quality or even to the surround sound effect;
4. Data transmission alongside with audio broadcast providing text-based information such as instant reports on finance, weather and traffic news etc;
5. More channels will be available in the same frequency spectrum as compare with AM and FM transmissions. Each 1.5MHz frequency spectrum of DAB can transmit six sets of programmes with CD quality.

In conclusion, DAB provides multimedia broadcasting environment that enables the media to develop a new market, and offers the audience better broadcast quality and service.

Technical information:

Points to note:

1. Since it is a trial, signals may be interrupted temporarily without prior notice.
2. The receiver selects channels automatically. When reception is in normal condition, display screen of the receiver will show the name of the channel: RTHK R5 IN DAB, RTHK PTC IN DAB and so on.
3. You are invited to express your comments through our website at www.rthk.org.hk/about/digitalbroadcasting/. Thank you.

�@�@Digital Sound Broadcasting (DSB) offers a robust form of transmission in the broadcasting industry, using digital compression technology to deliver audio, text, pictures and data by reducing transmission bandwidth requirements, as well as storage requirements and provides digital quality and reliability.
The DSB system serves an area by using one single frequency (Single Frequency Network). This significantly expands the number of channels available and allows for a more efficient use of the available spectrum as well as more interaction with audience members.

DSB has the potential to offer consumers territory-wide high-quality transmission of all existing radio stations plus dozens of new ones without distortion and interference. DSB offers the industry including public broadcasters a means of providing more choice.

RTHK, together with the Information Technology and Broadcasting Bureau, Hong Kong Commercial Radio & Metro Broadcast Corporation, ran tests on digital signals in 1998 on L-Band �V originally from two transmitter sites �V Mount Gough and Beacon Hill. With the digitization of broadcasting platforms, the path to enhanced broadcast services has been laid.

In 2004, RTHK intends to commence tests on digital broadcasting in two phases. In March, test on Digital Radio Mondiale (DRM), the digital system for medium-wave and AM, has been held. Another test on Eureka 147 DAB Band III is commenced in September. During the trial, programmes of AM and FM stations will be relayed. From April to May, 2005, RTHK has set up trial points at different locations for the public to experience the high sound quality of this new technology.

As the public broadcaster, RTHK should continue to catch the wave of the booming tech industry and research into the possibility of introducing more platforms so that broadcasters can explore the enhancement of the quality and range of the public service provision.