Glossary: D


A device that decodes a scrambled signal and allows access to a broadcast service: normally used in conjunction with a smart card.


A popular term for a digital receiver for satellite, terrestrial or cable television. May contain a decoder.


The replacement for analogue recording and transmission systems where the signal is a sequence of ones or zeros, or on-or-off states.

Digital compression

The reduction of the data needed to be broadcast (video, audio or data) giving minimum loss of received quality so as to make maximum use of the available transmission capacity.
Thus, several digitally compressed TV channels can be transmitted in the space required for a single uncompressed analogue TV channel. The main way that compression works is by eliminating some of the redundant data in the signal.

Digital TV

A more efficient means of transmitting television services that offers more channels and interactive services, as well as improved picture and sound quality.


To convert analogue signals into digital ones.


Digital Satellite Equipment Control, DISEQCTM

A standardised "communication protocol" to control external switches or LNBs from a satellite receiver, for example. Makes installation easier, since more than one LNB or dish can be connected to a satellite.


Satellite dish

Part of satellite reception equipment which reflects and concentrates at its focal point the signal coming from the satellite.

Dolby Digital

A high-quality surround sound system for films and TV programmes that is the successor to Dolby Pro-Logic.

Dolby Pro-Logic

A high-quality surround-sound system for films and TV programmes that was superseded by Dolby Digital.


A signal channel or path from the satellite to all types of reception sites on earth.


Direct to home

The direct reception of satellite transmissions by households via a dish, LNB and set-top box.


Direct to office

The reception of satellite programmes via an individual dish or shared dish in an office.


Digital Theatre System

A high-quality digital surround sound system for films and TV programmes: an alternative to Dolby Digital.


Digital terrestrial television

The national free-to-air digital TV and broadcast system that will replace the national free-to-air analogue terrestrial TV system by 2012.


Digital television


A monoblock/one-piece LNB developed by ASTRA that provides simultaneous access to its 23.5° and 19.2° east satellites using a single dish. There are two versions: the Twin for up to two set-top boxes, and the Quad for up to four.


A digital video format offering the best picture and audio quality of the domestic video systems.


See Digital Video Broadcasting (DVB) Group.

Digital Video Broadcasting (DVB) Group

The Digital Video Broadcasting group comprises over 200 organisations from 23 countries and developed the specifications for the transmission of MPEG-2 signals by satellite, cable and terrestrial links. These specifications are also a European Telecommunications Standards Institute (ETSI) standard.


Digital versatile disc

A compact disc lookalike for films, computer data, multimedia and audio.


Digital video recorder

Equipment such as DVD recorders and TV set-top boxes with a hard disk that allow consumers to record TV programmes on to a DVD or hard disk.