CAI

Fourth Generation. Mobile devices using LTE standards

Advanced Communication Technologies and Services. A European Commission research and development funding programme including digital broadcasting and next-generation Internet.

A motorised device that drives a multi-satellite dish to allow it to point at different satellites.

Amplitude Modulated/Modulation

A circuit that increases the power or voltage of a signal.

The strength or magnitude of a signal.

A mode of transmission of information. An analogue waveform has a physical similarity with the quantity it represents.

Used to differentiate a 16x9 widescreen picture which fills the whole frame, from a 16x9 letterbox with blank lines at the top and bottom of the frame. The US does not recognise anamorphic in the context of television - their equivalent term is 16x9 full frame.

A device which can receive and or transmit radio frequency signals whose format will depend on the type of signals used.

Authorised Sky Agent - A supplier/installer authorised by Sky.

American Standard Code for Information Interchange.

Authorised Sky Homes Agent - As above but authorised to supply / install equipment for local council’s etc.

The ratio of width to height for a TV screen.

A group of satellites used for UK and European reception located at 19.2°E, These supply hundreds of analogue and digital channels. Astra 2A-2D orbit at 28.2°E and provide the Sky Digital signals.

The loss in power of electromagnetic signals between transmission and reception points.

A passive device that decreases signal power.

Horizontal direction expressed as the angular distance between the direction of a fixed point (as the observer's heading) and the direction of the object.

A balance-to-unbalance transformer (sometimes an integral part of an aerial) used to match an unbalanced coaxial cable to a balanced device such as an aerial dipole or receiver input.

The total range of frequencies occupied by a signal. It is normally measured between half-power points.

The band of frequencies containing information after demodulation.

An aerial acceptance angle measured between half- power points.

A certification by an independent authority.

Bit Error Ratio.

In-home radio system for communicating between devices over short distances (

The principle centre axis of an aerial or dish antenna.

A number of programmes grouped within a multiplex.

The interwoven outer conductive layer of coaxial cable made up of several bare conductors coming together to form a solid or nearly solid layer or shield. Braid is rated by percentage of coverage and by pixels per inch. Pixels per inch indicate the number of crossings of the braid in one inch of cable.

The relevant Standard currently in force as published by the British Standards Institution or the harmonized European Standard, BS EN.

A member who has one or more engineers who have a qualification in the design, installation and maintenance of systems. (See System Installer)

A energy storage device that is formed wherever an insulator separates two conductors between which a voltage difference exists. Capacitance is measured in "Farads".

A dish with a paraboloid prime focus main reflector and a convex sub-reflector.

Cat5 is a generic term generally used for Category 3, 5, 6, 7, 8 ‘twisted pair’ cable which is utilised in structured networks.

Enhanced’ Cat5 cable where the individual twisted pairs are either twisted in differing degrees of ‘tightness’ together per pair. When used in audio /video networks this assists in overcoming problems such RGB ‘skew’ and audio imbalances etc.

Community Antenna Television. A master antenna and distribution system capable of receiving, amplifying and distributing a television signal via a coaxial or fibre cable to television receivers in a large community. Also known as 'Cable Television'.

Code Division Multiple Access. A numerical standard for data transmission.

Consultants Europe. Certification Scheme for equipment compliance.

The teletext service of the BBC.

The hue and saturation of a colour. A chrominance signal carries the colour information.

A widescreen TV picture format, usually 16:9.

The circular orbital belt 35 786Km above the equator, at which all satellites appear to be stationary.