Analogue Broadcasting – The traditional way of broadcasting television and radio. An analogue signal directly represents the pictures and sound. This is unlike digital broadcasting which operates by coding the pictures and sound into ‘computerised’ data.
Analogue Switch Off (ASO) – Analogue Switch Off (ASO) is the date when Ireland will stop broadcasting the existing analogue television signal. The EU has mandated the end of 2012 as the final date for Analogue Switch Off (ASO). Aside from improvements in pictures, sound and range of services, digital transmission allows for far more efficient use of valuable radio spectrum than analogue transmission. From a national perspective, moving to digital will free up radio spectrum for use by other important communications services such as broadband, mobile TV or other mobile services. The Government has estimated the value of such services at €500 million over the next ten years.
Analogue Terrestrial TV channels – The analogue TV channels broadcast in Ireland and received via an aerial are RTE One, RTE Two, TV3, TG4.
Antenna – Device designed to receive the radio wave broadcast by TV stations.
Aspect Ratio – This defines the shape of a TV screen and is the relationship between the width and height of the screen. A standard TV set has an aspect ratio of 4:3. A widescreen set has an aspect ratio of 16:9, giving a ‘letterbox’ shape like that of a cinema screen. The programmes on most of the major TV channels are now broadcast in 16:9 format.
Audio Description – A spoken commentary on TV that describes what is happening on screen, particularly useful for visually impaired viewers. The commentary fits in between dialogue and describes action sequences, facial expressions, costume, scenery and so on.
Broadcasting spectrum – the range of radio frequencies that may be used for broadcasting. A single radio frequency (RF) channel takes up a certain amount of frequency space. In general only one signal transmitted on that RF channel can be received without interference at any one location. In analogue systems one programme service, e.g. a single TV channel occupies one radio frequency channel. In digital systems a number of programme services will occupy a single radio frequency channel. Thus compared to the analogue systems of the past, digital systems can deliver the same services in less spectrum.
Cable TV – Broadcast signals are pulled off-air from terrestrial or satellite transmitters and distributed to receiving devices via co-axial or fibre cable. For digital cable, a decoder box is used to receive and decode any digital signals transmitted. Cable television was introduced in Ireland in the late sixties and is currently being upgraded to provide for digital transmissions.
CANAL+ – The France based Canal+ Technologies is an international provider of digital and interactive TV software solutions.
Coaxial cable – A type of metal transmission cable containing two conductors where the outer conductor forms a cylinder that encloses the inner conductor. The two conductors are separated by air or some other insulator.
Compression – Term that refers to the reduction of the size of digital data by removing non critical information.
Conditional Access (CA) – Conditional Access systems restrict television program access to certain groups of users either because of concerns for privacy or the desire to collect revenue for the service. Providing conditional access requires secure encryption of the program content, secure decryption in a set-top-box for each viewer, and an embedded serial number that is registered in a central conditional access system database.
Cathode Ray Tube (CRT) – Cathode ray tube, as in the standard type of large-bodied TV set.
Data / Broadband services – It is possible to send computer files or provide internet type services such as web browsing and email over a DTT network. Computer files are represented as a collection of “1″s and “0″s. Signals on DTT also consist of ‘1s’ and ‘0s’ so once a file is in this form the transmission process is identical.
Decoder – A device that turns digital signals back into analogue sound and picture signals. It may come in a set-top box, or be built into a TV set or PVR.
Digitag – DigiTAG aims to encourage and facilitate the introduction and implementation of digital terrestrial television services using the standards developed by Digital Video Broadcasting (DVB).
Digital – The new way of broadcasting television and radio. A digital signal codes the pictures and sounds into ‘computerised’ data. This allows the information to be transmitted more easily and more efficiently than analogue signals. The signal then has to be turned back into pictures and sounds by a decoder.
Digital Freesat Service – Freesat is the BBC owned trademark name for free to air digital satellite television services delivered to the UK market. It was established to complement Freeview – the UK free to air Digital Terrestrial Television platform.
Digital TV Group (DTG) – Formed in the mid 90s, originally to facilitate the introduction of digital terrestrial TV in the U.K., the group is the fulcrum of U.K. digital TV. The group is currently focused on digital switchover and the rich media services and products it will help enable. Emerging consumer devices and experiences include high definition TV, mobile TV, video-on-demand, broadband TV and TV metadata (see below).
Digital Tuner – The digital tuner serves as the decoder required to receive and display digital broadcasts. It can be included inside a TV or set top box.
DVB – Digital Video Broadcasting, a European consortia for the standardization and deployment of digital television via terrestrial broadcast and satellite.
Digital Switchover – The process of switching from analogue to digital broadcasting. Most European countries plan to achieve digital switchover by 2012.
Digital Terrestrial Television (DTT) – Digital TV that is received via a standard aerial.
DTT Receiver – This is the device that processes the incoming signal from the DTT transmitter and turns it into a format which can be displayed on the TV. It can take the form of a set top box or may be integrated into the TV itself.
The essential role of the DTT receiver is to receive, decode and decompress digital data to produce audio and video signals that can be displayed. It is a custom computer system whose processing power can vary considerably depending on the functionality and sophistication of the receiver. All receivers use an Operating System to perform its basic functions. Some receivers offer a return path, via a telephone or broadband connection, to allow two-way communication or interaction. This generally requires a built in modem and is not a regular feature of most receivers currently on the market.
Digital Video Recorder (DVR) – Same as a Personal Video Recorder (PVR).
Downlink – A signal sent down from a satellite to the ground.
Electronic Programme Guide (EPG) - software built into a set-top box that gives on-screen listings of what’s on TV now and for a number of days or weeks ahead. You can use the EPG to go straight to a programme you want to watch or to select something to record.
ETSI – The European Telecommunications Standards Institute (ETSI) is an independent, non-profit organization, whose mission is to produce telecommunications standards for today and for the future.
Freeview – The main UK digital terrestrial television service.
Hard disk (or hard drive) – An electronic storage device used to store large amounts of digital information. Computers have a hard disk inside, and so do personal/digital video recorders (PVRs or DVRs). You can store many hours of TV programmes on a PVR’s hard disk.
HD (High definition) – HD TV has up to four times as many pixels (dots on the screen) as standard-definition TV. The pixels make up the lines on a screen – standard screens have 625 lines, HD screens have 720 or 1080 lines. This gives a clearer, sharper picture with much more detail.
HDMI – High-definition multimedia interface: a digital connection using a single cable for high-quality video and audio.
HDTV Tuner – (also known as Decoder or Receiver)- a device capable of receiving and decoding HDTV signals. HDTV tuners can be either built into a TV set (called an integrated digital TV set) or be a standalone device such as a set top box.
Information services – The launch of DTT would allow the introduction of a digital version of teletext (Digitext). Digital teletext would offer the services provided by traditional teletext but with enhanced features such as faster page transitions, more aesthetically pleasing page layout, multiview capabilities and the possibility of regionally specific pages.
Integrated Digital Television (iDTV) – A TV set with a built in receiver which carries out the functions of a set top box. Such a TV would not need a set top box to display unencrypted TV stations.
Interactive services – Digital TV will offer “red button features” where pressing a button on the remote control will activate enhanced features in the set top box providing additional information about programmes, alternative news stories or sports coverage along with the opportunity to join in quizzes or vote in polls.
Liquid Crystal Display (LCD) – Liquid crystal display: a technology that displays a picture on a flat-panel screen. It is particularly suitable for large-size TV screens.
Metadata – Data about data. Metadata describes how and when and by whom a particular set of data was collected, and how the data is formatted. Metadata is essential for understanding information stored in data warehouses and has become increasingly important in XML-based Web applications.
MHEG – Multimedia and Hypermedia information coding Expert Group developed this ISO standard for multimedia scripting, display and user interaction. It is suggested as an alternative to HTML and Java for enhanced television.
MHP – Multimedia Home Platform (MHP) is a standard within the DVB for enhanced television. It defines a generic interface between interactive digital applications and the terminals on which those applications execute. It supports many kinds of applications including electronic program guides, information services, synchronous enhancements, e-commerce and secure transactions. It requires a Java run-time engine within the set-top-box, allowing complex applications to be developed.
Middleware – Middleware is a layer of software that runs on top of set top box operating systems (OS) creating a consistent environment to run application software over a wide variety of set top boxes.
MPEG – The Moving Picture Experts Group, a working group of ISO/IEC, has developed international standards for compressed digital video and audio. MPEG-1 provides resolution up to 1/4 of standard definition video, at bit rates up to roughly 1.5 Mbits/second. MPEG-2 provides a family of compression profiles and levels, including ones for High Definition Television. MPEG-4 provides an even higher range of resolution options, plus the ability to include image objects. MPEG-4 is likely to be the standard used for the transmission of High Definition (HD) content due to its enhanced compression ability and the large quantities of information contained
in HD signals. MPEG 4 is the standard used for SAORVIEW.
Multichannel Multipoint Distribution Service (MMDS) – MMDS is a telecommunications technology that offers an alternative method of cable television programming reception. Signals are in the form of high frequency radio waves that are broadcast over the air. MMDS is used in less populated areas where a special aerial receives the signal that would be distributed along a cable in more populated areas.
Multiplex (mux) – A multiplexer is a device taking a single input and selects one of many outputs and connects the single input to that particular output line. In practical terms it might be a single frequency that contains a number of different digital TV or radio programmes.
Multiview – Multiview is a feature that allows two channels to be viewed on screen simultaneously.
Must-Carry – Rules that require certain television or radio channels to be carried over certain networks. The reasons invoked for same typically include universal accessibility of certain radio and television programmes and the need to guarantee a pluralistic offer to the public.
Near universal coverage – It is very difficult for a broadcasting service to offer coverage at all geographical locations in the country. It is anticipated that DTT will provide coverage of around 98%.
Personal Digital Recorder (PDR) – Same as a Personal Video Recorder (PVR).
Personal Video Recorder (PVR) - Also known as a DVR (digital video recorder) or PDR (personal digital recorder). It records TV programmes digitally on to a hard disk (like saving information on a computer), instead of on video tape or DVD. It has an electronic programme guide built in, and allows you to pause and ‘rewind’ a programme while you are watching it.
Pixels – Picture element: a single dot on a TV screen (or a computer screen or digital photograph). Typically thousands of pixels make up a picture and the more pixels there are the better the quality of the picture. Or
Pixel is actually two words combined – “Picture” and “Element.” Pixels are tiny samples of video information, the “little squares” that “add up” to an entire picture. A pixel is the smallest area of a television picture capable of being sampled and transmitted through a system, and displayed on a monitor.
Plasma – A technology that displays a TV picture on a flat-panel screen by using gases behind the glass. It is particularly suitable for large-size screens and is good for HD TV.
Platform – In broadcasting, a system for delivering TV and radio services. For example, digital TV is delivered mainly on terrestrial, satellite, cable and broadband platforms.
Receiver - Equipment that receives signals from a transmitter and allows you to see and/or hear TV or radio broadcasts. TV sets (both analogue and digital), digital TV set-top boxes, and radio sets are all examples of receivers.
Relay – A low-power transmitter that receives signals from a main transmitter and retransmits them to a localised area.
Resolution -The amount of detail that can be seen in a broadcast image. For television, resolution is measured in horizontal lines displayed.
Satellite – Satellite broadcasting services are received through geostationary satellites above the earth. The satellite receives signals transmitted from an uplink facility on the ground and broadcasts them so that they may be received by a dish antenna connected to a satellite receiver set top box. Satellite broadcasts have a wide coverage area and are subscription based.
Scart – A Scart lead has a large, rectangular, 21-pin plug at each end. It is the most common way to connect equipment such as TVs, video recorders, DVD players and set-top boxes.
Set top box – An electronic device which can receive and decode digital TV signals so that they can be displayed on an analogue TV.
Smart card - Also called a conditional access viewing card: a plastic card inserted into a slot in a set-top box or TV that decodes signals and allows you to receive encrypted digital services.
Spectrum – A range of electromagnetic radio frequencies used in the transmission of radio, data, and video.
Standard Definition (SD) – A level of screen resolution (no of pixels on the screen) that produces a picture quality comparable with good quality traditional analogue TV reception. Standard Definition screens have 625 lines of pixels on the screen.
Terrestrial Television – Television broadcasts, over radio waves, which are transmitted from a transmitter located on the earth – generally on a mountain or hill site and intended for direct reception by the general public.