DAB
Acronym for Digital Audio Broadcasting. Standard procedure for the digital transmission of radio signals developed in the EU research initiative, EUREKA 147.
DAB+
DAB+ is the evolution of the DAB standard. The technical difference lies in the audio coding, i.e. the two standards use different methods to process the data before and after transmission. DAB uses MPEG-1 layer 2, whereas DAB+ uses MPEG-4. With DAB+ it is possible to broadcast 18 programme services (stations) simultaneously (compared to 12 with DAB); it is also possible to transmit images. Switzerland only operates DAB+ networks (with the exception of three DAB programme services until 2015).
Data compression
Data compression is one of the most important achievements of digital technology. It enables information to be reduced by exploiting the psycho-acoustic and visual characteristics of the human senses of hearing and sight, filtering out non-audible and non-visible elements. This is why 4 to 10 times more programmes can be transmitted with digital television compared with analogue television, where only one programme can be transmitted per channel.
Data rate
Number of bits transmitted per unit of time.
Data services
Any kind of one-off or regular transmitted digital data which is transmitted in packet mode or stream mode as either programme associated data (PAD) or non-programme associated data (NPAD).
Descrambler
Electronic device in the television set (or as an add-on device to the TV set) in which incoming signals in encrypted or scrambled form are reassembled. A scrambling/descrambling system is an important prerequisite for pay-TV. Only those who have paid a fee can receive the encrypted pictures and play them back without interference.
Digital Multimedia Broadcasting (DMB)
Digital Multimedia Broadcasting (DMB) is a digital signal processing standard enabling the transmission not only of voice, text and music but also of still and moving pictures. DMB is a further development of the digital standard DAB (Digital Audio Broadcasting).
Digital Radio Mondiale (DRM)
Method of digitally transmitting radio signals on short-wave bands (also acronym for the consortium of the same name).
Digital Video Broadcasting (DVB)
Originally a European initiative for developing and standardising digital transmission standards for television signals. DVB has since become a worldwide project organisation with over 300 members from all five continents. The organisation's headquarters is in Geneva.
Digital Video Broadcasting Handheld (DVB-H)
Digital Video Broadcasting - Handheld is the standard for digital transmission of radio and television programme services to mobile terminals. This 2004 standard is obsolete and no longer in use.
Digital Video Broadcasting Terrestrial (DVB-T)
Standard procedure for the digital transmission of TV signals developed by the DVB project group. T stands for terrestrial broadcasting. DVB can also be broadcast by satellite (DVB-S) and cable (DVB-C).
Digitisation
Translation of information (e.g. electromagnetic oscillations) into the binary system of ones and zeros. The main advantage of digitisation is the fact that all different kinds of data can be transmitted together, irrespective of the mode of transmission.
Display
A very broad term to describe displays, from simple numerical displays on pocket calculators through to computer screens and large home entertainment screens.
Electronic Program Guides (EPG)
Navigation aids (Electronic Program Guides; EPG) which enable the public to choose from the broad offering of a digital television (several hundred stations). Consumers are given instructions on a user guide which collates data on the individual programmes and groups them together and then displays them on the screen in the form of a graphical menu so that users can directly select the programme they want (similar to TV and radio listings or an internet browser). EPGs can be offered by broadcasters, cable network operators or even by independent companies, for example by a publishing house.
Ensemble
Package (also called multiplex) of about 5-9 radio programmes and additional data services with a fixed total capacity. However, this can be divided up flexibly among the various programmes and services. Every ensemble or multiplex is broadcast in a particular area in the same way as a normal VHF radio programme, e.g. within the Federal Republic of Switzerland, only in one town or maybe even in the whole of Germany. Many different ensembles can therefore be broadcast in one area. However, an ensemble or multiplex uses only a single frequency for this and has a unique identification number and a name. The extent of the ensemble's broadcast area is also called the coverage. The DAB multiplex data stream has a maximum capacity of approx. 1.7 Mbit/s, normally shared by a number of radio programmes (audio streams) and data channels (NPAD, packet mode). The name multiplex relates to the fact that the individual data streams are multiplexed (that is, they are transmitted alternately in chunks). A multiplex needs a bandwidth of 1.5 MHz on the frequency band. The total amount of data, services and programmes transmitted in a multiplex is also called the ensemble. (See also Bouquet and COFDM)
EUREKA
Europe-wide network for industrial research and development: framework for cross-border co-operation projects in industry and science.
