Radio technology is undergoing a metamorphosis, with exciting implications for actual and potential users. For 20 yrs there seemed no prospect of innovation in radio systems but increasing complexity of silicon devices at falling cost has brought about a revolution in thinking and in opportunities for new communication systems. Access to both mass memory and complex signal processing is expanding the frontiers of radio communications technology dramatically. Personal communications, business data distribution and computer-to-computer communication are only some of the significant areas already in the process of being revolutionized by the new technology. Developments in linear technology and cellular techniques, together with the now recognized advantages of short-range radio, mean that new radio systems will support a far greater number of users from the available spectrum. And undoubtedly, cheaper bandwidth and signal processing will spur new approaches to information packaging and delivery systems.
Exhibit 1 - Benefits of Digital Audio Broadcasting
* stereophonic sound services with subjective quality indistinguishable from high-quality consumer digital recorded media such as compact disc
* improved reception to portable and mobile (i.e. vehicle-mounted) receivers
* improved spectrum efficiency with reduced radiated power requirements for coverage of any given area
* enhanced service-related facilities such as station identification, program labeling (e.g., artist name and song title), copyright control, conditional access, services for hearing impaired
* value-added services with different data capacities (e.g. traffic message channels, business data, paging etc)
* the capability to trade-off sound quality and the number of available sound programs
* local, regional or national service coverage using terrestrial and/or satellite-based transmitters
* use of a common receiver for reception of both terrestrial and satellite-delivered services
Digital Audio Broadcasting (DAB) offers a full-digital radio broadcast system for fixed, portable and especially mobile receivers. It brings a superb sound quality (and powerful data service) to homes and cars.
The World DAB Forum is an international non-governmental organization whose objective is to promote, harmonize and co-ordinate the implementation of Digital Radio services based on the Eureka 147 DAB system.
With 2 billion fixed or mobile receivers in the world, we are talking about an enormous industrial market opening up in the coming years as a result of one of the most important technological innovations since the start of broadcasting. The sound coding is several times more efficient than conventional systems by making use of the psycho-acoustic properties of the human ear. It maintains the subjective quality of the compact disc while dramatically reducing the transmitter bit rate (from 1.4Mbps to about 200Kbps per stereophonic sound). In addition, data services can be provided in the same digital multiplex with a capacity sufficiently high for even still picture transmission and, of course, program related data.
The transmission quality is simply sensational. The modulation and channel coding scheme is resistant to multi-path propagation. Because of its immunity to echoes, a network can consist of transmitters all operating at the same frequency (a so called Single Frequency Network [SFN]). The modulation technique offers high spectrum efficiency and unimpaired reception in moving vehicles. It is called COFDM, which stands for Coded Orthogonal Frequency Division Multiplexing. The coded sound signal can be recorded on Magneto-Optical Disc (MOD), and this allows storage of up to 16 hours of sound on a CD-size disk with the new recorders.
The DAB System was developed by the Eureka 147 Project - an international consortium of broadcasters, network operators, consumer electronic industries and research institutes. They came together to develop the DAB standard, which is currently being implemented and put to use worldwide.
As the work of the Eureka 147 Consortium came to an end in January 2000, having perfected the DAB system, it was found appropriate that the Eureka 147 Consortium should merge into the World DAB forum. Thus allowing the World DAB forum to continue with the implementation phase that is currently being accomplished.
The goal of the Forum is to convert a brilliant piece of engineering achievement into a worldwide commercial marketing success, to the lasting economic and social benefit of all concerned.
Source : Verizon learning Centre
Exhibit 1 - Benefits of Digital Audio Broadcasting
* stereophonic sound services with subjective quality indistinguishable from high-quality consumer digital recorded media such as compact disc
* improved reception to portable and mobile (i.e. vehicle-mounted) receivers
* improved spectrum efficiency with reduced radiated power requirements for coverage of any given area
* enhanced service-related facilities such as station identification, program labeling (e.g., artist name and song title), copyright control, conditional access, services for hearing impaired
* value-added services with different data capacities (e.g. traffic message channels, business data, paging etc)
* the capability to trade-off sound quality and the number of available sound programs
* local, regional or national service coverage using terrestrial and/or satellite-based transmitters
* use of a common receiver for reception of both terrestrial and satellite-delivered services
Digital Audio Broadcasting (DAB) offers a full-digital radio broadcast system for fixed, portable and especially mobile receivers. It brings a superb sound quality (and powerful data service) to homes and cars.
The World DAB Forum is an international non-governmental organization whose objective is to promote, harmonize and co-ordinate the implementation of Digital Radio services based on the Eureka 147 DAB system.
With 2 billion fixed or mobile receivers in the world, we are talking about an enormous industrial market opening up in the coming years as a result of one of the most important technological innovations since the start of broadcasting. The sound coding is several times more efficient than conventional systems by making use of the psycho-acoustic properties of the human ear. It maintains the subjective quality of the compact disc while dramatically reducing the transmitter bit rate (from 1.4Mbps to about 200Kbps per stereophonic sound). In addition, data services can be provided in the same digital multiplex with a capacity sufficiently high for even still picture transmission and, of course, program related data.
The transmission quality is simply sensational. The modulation and channel coding scheme is resistant to multi-path propagation. Because of its immunity to echoes, a network can consist of transmitters all operating at the same frequency (a so called Single Frequency Network [SFN]). The modulation technique offers high spectrum efficiency and unimpaired reception in moving vehicles. It is called COFDM, which stands for Coded Orthogonal Frequency Division Multiplexing. The coded sound signal can be recorded on Magneto-Optical Disc (MOD), and this allows storage of up to 16 hours of sound on a CD-size disk with the new recorders.
The DAB System was developed by the Eureka 147 Project - an international consortium of broadcasters, network operators, consumer electronic industries and research institutes. They came together to develop the DAB standard, which is currently being implemented and put to use worldwide.
As the work of the Eureka 147 Consortium came to an end in January 2000, having perfected the DAB system, it was found appropriate that the Eureka 147 Consortium should merge into the World DAB forum. Thus allowing the World DAB forum to continue with the implementation phase that is currently being accomplished.
The goal of the Forum is to convert a brilliant piece of engineering achievement into a worldwide commercial marketing success, to the lasting economic and social benefit of all concerned.
Source : Verizon learning Centre