Glossary

A

AAC

Advanced Audio Coding is part of the MPEG-2 and MPEG-4 standards for audio compression. Promoted as a successor to MP3, also part of the MPEG standards, it offers higher-quality sound but takes up about the same amount of space and includes digital copyright protection.

AC-3

Audio Coding 3 is the technical name for Dolby Digital's third generation surround sound system.

ADSL

Asymmetrical Digital Subscriber Line is a data communications technology that enables relatively fast data transmission over conventional copper telephone lines. With ADSL a single phone line can be used simultaneously for voice calls and data transmission. ADSL differs from DSL in that data download speeds are normally greater than upload speeds and is therefore said to be asymmetrical.

AMOLED

The term Active-Matrix Organic Light-Emitting Diode describes an especially thin and bright flat panel display technology which doesn't require a backlight and operates with very modest power requirements.

In this technology, Thin Film Transistors (a matrix of transistors and capacitors) are used to precisely control the light/colour levels of each organic LED in the matrix that makes up the pixels of it's display screen. This type of arrangement contrasts with passive-matrix displays which are controlled on a row and column basis - producing a lower defined image quality.

Analog TV

Analog TV signals are transmitted by radio waves and have been used for television broadcasts since the 1940s. The three main standards for Analog TV are NTSC, PAL and SECAM. Analog TV is being gradually phased out worldwide and will be replaced by Digital TV.

Artifacts

Unwanted visible effects in video such as ‘pixilation’, where some of the pixels or dots that make up a digital image appear as large blurred or coarse looking blocks.

Aspect Ratio

Refers to the width of an image relative to its height. The aspect ratio for standard TV is 4:3, meaning four units wide by three units high. HDTV has an aspect ratio of 16:9.

ATSC

The Advanced Television Systems Committee lends its name (or acronym) to the digital television standard that will replace the ageing NTSC standard in many of the countries where it is still in use. ATSC can accommodate widescreen resolutions up to 1920 x 1080 pixels and uses MPEG-2 video and Dolby Digital audio compression.

ATSC-M/C

Advanced Television Systems Committee-Mobile/Handheld promotes a technical standard that uses MPEG-4 or H.264 compression for transmitting video, audio and data to mobile devices in the USA.

Audio Description

Audio Description is a narrative soundtrack that describes what’s happening on screen.

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B

Bandwidth

The capacity of a transmission medium stated in bits per second (digital) or as a frequency (cycles per second for analog).

Bluetooth

Bluetooth is a radio technology that enables short range wireless connectivity and synchronization between compatible devices. It is said to be named after Harald Bluetooth, a Viking ruler renowned for his bridge building.

Blu-ray

Blu-ray is an optical disc format that can store 25 GB of digital information on a single sided disc, up to five times more than single layer DVD. Dual layer Blu-ray discs can store 50 GB of data, equivalent to 4 hours of high definition television. The standard uses blue-violet laser which has a much shorter wavelength than the red laser of CD and DVD. This means that the laser can focus on much smaller areas, allowing more data to be compacted on to the disc.

Bps

Bits Per Second is a measure of the rate at which data can be transferred. A single bit is the smallest unit of digital storage (binary 0 or 1), but rates of transfer are normally expressed in thousands (Kilo - Kbps) or millions (Mega - Mbps).

Broadband

Broadband is a contraction of the words ‘broad’ and ‘bandwidth’. Broadband contrasts with traditional telephony networks which have narrow bandwidth. Broadband systems are capable of moving a vast quantity of voice, data and video signals quickly over a single medium. Cable television uses broadband techniques to deliver dozens of channels over one cable with room left over for a fast connection to the internet.

Byte

A unit of digital storage consisting of eight bits. A sequence of eight bits can be used to represent a single text character. People often confuse the symbols for bits (b) and bytes (B). For example 1Kb (one thousand bits) is not the same as 1KB (one thousand bytes).

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C

CATV

Community Antenna Television or Cable TV provides for reception of TV signals via Hybrid Fibre Coax (HFC) cable systems rather than over the air.

Coaxial Cable

A high-capacity cable used in communications and video. Cable TV companies use coaxial cable between the community antenna and individual subscribers. Coaxial cable is so called because it is comprised of inner and outer concentric cables, surrounded by insulation. The inner cable carries information whilst the outer (mesh) acts as an electrical interference suppressor.

CDMA

Code Division Multiple Access was first used during World War II by the allies to hinder attempts by opposing forces to obstruct radio transmissions. Transmissions were split over several frequencies instead of just one, making it difficult for the enemy to pick up the complete signal.

Modern communications employing CDMA use a similar technique, where digital information is packaged, assigned a unique code and transmitted over a network, but not necessarily on a specific frequency channel. Each receiver on the network recognises its own code and picks up only that signal, thus allowing users to share network space whilst adding security. CDMA is fundamental in the operation of 3G mobile communication services worldwide.

CODEC

A contraction of the words COder and DECoder referring to software or hardware that compresses and decompresses audio and video data streams, the purpose being to reduce file size for fast transmission and to save on storage space without sacrificing too much quality.

Component Video

Component Video codes video signals as three separate components, one for brightness and the other two for colour. Component video provides a sharper image than composite video, where the process of combining separate signals as one results in some loss of quality. On video equipment, coaxial cables with RCA male plugs coloured red, green and blue are used to connect the three separate video streams - audio is connected separately.

Composite Video

Composite video is used to convey the image information in analog TV broadcasts, where brightness and colour signals are synchronized into one signal to save on bandwidth. On video equipment, the composite video signal is typically connected using a yellow coloured RCA jack and the sound by red and white coloured RCA jacks.

Compression

To understand why video compression is so important, consider the vast bandwidth required to transmit uncompressed digital TV pictures. An uncompressed video file can use up to 1 GB of storage for each minute of video. MPEG-2 compression, the standard for DTV, can reduce that figure by a factor of thirty with little or no loss in perceived quality, allowing four full range digital channels to be compressed into the same space required by a single analog channel.

Most video compression algorithms are lossy (sacrifice data for space), but take advantage of the fact that there is usually minimal difference in a succession of video frames. The process involves encoding distinct full frames and then the sequence of differences between similar frames. Image detail that does not change between frames is regarded as redundant and is discarded.

Contrast Ratio

Contrast ratio measures the difference between the brightest whites and the darkest blacks in a display. In theory, the higher the contrast ratio, the better a display will be at showing subtle colour details. In practice, anything over 500:1 will be imperceptible to the human eye. The measure of gray scale is a much more realistic indicator of display quality.

CRT

A Cathode-Ray Tube is a specialized vacuum tube in which images are created when an electron beam rapidly scans back and forth and up and down across the inside of a phosphor-coated screen. CRT’s have their advantages, but they are big and bulky and are being rapidly replaced by lighter more compact digital flat panel displays.

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D

DAB

Digital Audio Broadcasting is a technology for broadcasting audio programming in digital form. The standard benefits from being able to deliver your favourite radio station without any interference and stream text-based information that is related to the broadcast.

DAB-IP

Digital Audio Broadcast-Internet Protocol is a term used to refer to a set of DAB standards that enables IP (Internet Protocol) transport over DAB.

Deinterlace

The process of smoothing out picture flaws when converting an interlaced video signal to a progressive scan video signal. The image seen on a screen is comprised of horizontal lines of picture detail that are drawn in rapid succession from screen top to bottom. Interlaced images are drawn in two passes, one pass or field that draws the odd lines and then one that draws the even. The lines appear to blend and produce a complete image, but with a slight time lag between passes that can cause some picture distortion. Progressive scan images are drawn in a single pass with lines drawn sequentially and thus presents less distortion. Deinterlacers are found in HDTV’s and progressive scan DVD players.

Digital

Digital processing describes a method where distinct electronic or optical pulses can be used to represent the binary digits zero or one. In contrast to analog processing, where signals are sampled, digital processing is much more precise. Digital sound and video can be transferred and copied with no quality degradation.

Digital Dividend

Digital Dividend refers to the spectrum of freed up analogue radio frequencies or bandwidth made available to digital services resulting from the analogue to digital switchover.

DivX

DivX is a digital video compression format based on MPEG-4 technology that is able to compress lengthy video segments into small sizes while maintaining relatively high visual quality.

DMB

Digital Multimedia Broadcast is a transmission system for sending data, radio and TV to mobile devices. DMB can operate via satellite (S-DMB) as well as terrestrial (T-DMB) transmission.

Dolby Digital

Also called AC-3 or Digital 5.1, Dolby Digital is an encoding system that allows up to five separate surround-sound channels and one additional subwoofer channel (the .1 in Digital 5.1) to be compressed into a single stream of data. Dolby Digital sound is the official audio standard for HDTV and DVD.

DRM

Digital Rights Management or DRM is the catch-all phrase that refers to any technology that seeks to protect and control access to games, music, movies, or any other digital data from unauthorised copying.

DSL

Digital Subscriber Lines significantly increase the digital capacity of ordinary telephone lines and are able to carry both voice and data communications simultaneously. DSL is probably most useful in areas where faster alternative connections to the Internet are unavailable.

DTV

Digital Television is a catch all term used to describe TV broadcast by means of digital signals. DTV data is transmitted compressed and requires decoding by a specially designed television set, a standard receiver with a set-top box or a PC fitted with a television card. Digital television provides a much clearer picture, better sound quality, interactivity and more programming choices than analog TV broadcasts.

DVB

Digital Video Broadcasting is a term used to describe European digital broadcasting standards for cable, satellite, and terrestrial TV.

DVB-H

Digital Video Broadcasting-Handheld describes the standard for bringing broadcast services to battery powered handheld receivers. DVB-H has been officially selected by the European Commission as the mobile TV standard for Europe.

DVB-SH

Digital Video Broadcasting-Satellite Services to Handheld is defined as a system which is able to deliver Mobile TV and IP (Internet Protocol) based media content and data to mobile devices like cell phones, laptops and PDA's via satellite.

DVB-S2

Digital Video Broadcasting-Satellite second generation is an enhanced specification of the DVB-S standard, which it intends to replace. The standard retains backward compatibility with DVB-S but is much more efficient requiring less transmission space than its predecessor.

DVB-T

Digital Video Broadcasting-Terrestrial is a European standard for the broadcast of digital terrestrial television, audio and data. Existing analogue TV antennas are normally used to receive the transmission signals.

DVB-T2

Digital Video Broadcasting-Terrestrial second generation is essentially a DVB-T upgrade that allows for much more efficient use of the current terrestrial spectrum. The standard is seen as a way of delivering high definition terrestrial television or additional digital channels within existing broadcast space.

D-VHS

Digital-VHS (Video Home System) is a videocassette standard capable of recording HDTV via a FireWire connection.

DVI

Digital Visual Interface is a high-bandwidth video interface technology engineered to maximize the quality of flat panel digital monitors connected to video graphics cards. There are currently three types of DVI connections: DVI-Analog, DVI-Digital and DVI-Integrated.

DVI-A (Analog) carries a DVI signal converted to analog and although some quality is lost in conversion, the signal delivered is still better than that of standard VGA. DVI-D (Digital) supports digital to digital signal transfer, eliminating the need for analog conversion and resulting in better quality. DVI-I (Integrated) supports both, either analog or digital signal transfer.

DVI usually carries no audio data; it is possible however for a DVI port to transmit audio data to an HDMI connection if a DVI to HDMI cable is used.

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E

Encoder

Hardware or software used to encode/compress audio or video signals.

EPG

An Electronic Programming Guide is an on-screen TV program listing that allows viewers to navigate and select content by channel, category, name, time, etc, by use of their remote control, a keyboard or phone keypad.

Encryption

The process of encoding information to protect it from unauthorised viewing or use. The reverse process, decryption, restores information to it's original state.

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F

Flat Panel Display

A Flat Panel or flat screen is a thin lightweight video display based on liquid crystal technology. Unlike cathode ray tubes that scan pictures to the screen with an electron gun, flat panels use fixed pixel arrays. The number of rows and columns in the pixel array define the displays native resolution, the setting for best picture quality.

Freesat

A UK based interactive service by which you can receive free digital TV and radio channels through a satellite dish. There is no contract, just a one-off payment for equipment.

Freeview

A UK based interactive service by which you can receive free digital TV and radio channels through your normal TV aerial. There is no contract, just a one-off payment for equipment.

FTP

File Transfer Protocol is a commonly used protocol for transferring data from one computer to another through a network.

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G

GPS

Global Positioning Service uses a satellite system to transmit precise microwave signals that enables GPS receivers to determine their location, speed, direction and time. Navigation satellite systems are also used in the synchronization of telecommunications networks.

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H

H.264

A codec capable of compressing high definition video such as Blu-ray and HDTV. Also known as MPEG-4 Part 10, Advanced Video Coding. The standard is the result of the efforts of the Joint Video Team (JVT), a collaboration between the Motion Picture Experts Group (MPEG) and the ITU-T Video Coding Experts Group (VCEG).

HDCP

High Bandwidth Digital Content Protection is a form of digital copy protection developed by Intel to prevent unauthorised reproduction of digital media as it moves across a compliant audio/video connecter.

HDMI

High Definition Multimedia Interface is a standard for consumer electronic devices that supports enhanced or high-definition video plus multi-channel digital audio and digital copy protection on a single compact connector. The standard is intended to replace all previous connectors such as: DVI, S-Video, coaxial, RCA audio, composite and component video cables.

HDTV

High Definition Television is a digital video format with display resolution up to five times that of conventional television, producing a very clear picture and providing compact disc quality surround sound.

There are two main HDTV formats in popular use which are labeled 1080i or 1080p (referred to as Full HD) and 720p. The numbers represent the number of lines used to make up the picture (the more the merrier). Analog TV uses up to around 400,000 picture elements (pixels), while HDTV, with 1080 vertical lines and 1920 horizontal pixels, uses more than 2 million pixels to display an image. The letter suffix ‘i’ stands for interlace and ‘p’ for progressive (see interlaced scanning for an explanation of the terms). Both formats display pictures with a 16:9 aspect ratio known as widescreen.

Although full HD (1080p) is now an established standard for HDTV screens, it is not an official HD broadcast format, however to take full advantage of Blu-ray discs and game consoles a full HD enabled screen is the better choice.

HFC

Hybrid Fibre Coax is a technology that combines optical fibre and coaxial cable in the same network. Fibre cable can carry more data and is more resistant to electrical interference than the coaxial, but is more expensive. If we compare the network to a tree, then the fibre optic cable is the trunk and the coaxial cables are the branches that connect end users to the network.

Hz

Hertz is the base unit of frequency measurement. A frequency of 1Hz means one cycle per second, a frequency of 1000Hz means 1000 cycles per second. Computer processor speeds and radio frequency are commonly measured in Hz.

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I

Interlaced Scanning

With interlaced scanning the lines that make up a TV picture or ‘frame’ are split in to two fields of odd and even numbered lines. To produce a full picture, the fields are alternately ‘painted’ to the frame line by line fast enough so as not to notice what's happening. Fields are painted at a rate of between 50 and 60 per second to produce 25 to 30 frames per second video (25 for PAL/SECAM and 30 for NTSC systems).

In contrast, progressive scanning displays the entire frame in a single sweep at frame rates of up to 60 per second. This results in twice the picture information of an equivalent interlaced signal, but requires double the bandwidth. Since bandwidth is limited, this explains why HDTV signals are delivered in progressive format for lower resolutions (720p) and interlaced for higher resolutions (1080i).

Internet

The Internet is a worldwide electronic communication network used for information exchange and sharing.

IP

Internet Protocol describes the procedure by which data is packaged and sent from one device to another over a network.

IPTV

Internet Protocol TV describes a method of distributing digital television over the Internet (or network) using Internet Protocol. The service uses two way signaling that enables a highly customized and interactive user experience.

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L

LAN

A Local Area Network is a network covering a small geographical area such as a home, office or small group of buildings.

Letterbox Mode

Letterboxing is a method of presenting widescreen images on a standard screen television while preserving the aspect ratio of the original video content. The picture is scaled down to fit the available width of the television screen leaving space above and below the picture which is displayed as horizontal black bars.

Linear Channel

Service delivery on a schedule, where the audience tunes in to a particular channel on a particular day at a particular time.

Lossy and Lossless

Digital file sizes can be reduced using either ‘lossless’ or ‘lossy’ compression techniques. Lossless techniques are used where it is important that the decompressed file is identical to the original. Lossy compression produces much smaller files than lossless, but some data is sacrificed, the decompressed file will be different to the original.

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M

MBMS

Multimedia Broadcast Multicast Service describes a technology that offers a cost effective way for cellular network operators to use their existing network infrastructure to transmit digital TV and multimedia services to mobile devices. With support for both broadcast and multicast services, content can be delivered to all subscribers or to just a specific group. With this technology in place, operators can quickly broadcast emergency alert information, traffic, weather, news and such like to targeted end users.

MBSAT

Mobile Broadcasting Satellite serving Japan and Korea.

MediaFlo

MediaFLO describes a technology from a company called Qualcomm that can be used to broadcast data to portable devices such as cell phones, laptops and PDA's. Broadcast content can include live audio and video streams, non-real time VOD, as well as IP data such as share prices, sports results, and news bulletins.

The “FLO” in MediaFLO stands for Forward Link Only, meaning that the data transmission path is one-way from the transmission point to the mobile device. The MediaFLO system transmits data on a frequency separate from the frequencies used by current cellular networks.

MHEG-5

Multimedia and Hypermedia information coding Expert Group. MHEG should not be confused with MPEG the video compression technology. MHEG-5 is a programming language used to provide interactive services for digital TV.

Mobile TV

TV viewable on a mobile device by means of technologies such as DVB-H, DVB-SH, DMB and MediaFlo.

Mobisodes

TV programs and shows which have been specifically edited, formatted and even filmed with Mobile TV in mind.

Modulation

In terms of modern communications, modulation is the addition of a signal (data) to an electronic or optical signal carrier. In less modern terms, think of it as waving a blanket over a stream of smoke to make smoke signals. The smoke is the signal carrier and the blanket waving the signal, a knowledgeable person seeing the smoke signal could interpret its meaning, or put in modern terms, demodulate the signal.

MP3

MPEG Audio Layer 3 developed in Germany as part of the MPEG specifications is an audio compression technology that provides Compact Disc quality sound in a much smaller file size. The standard is capable of 10:1 compression with no noticeable loss in quality, which explains its popularity for use on the internet and mobile devices.

MPEG

The Moving Pictures Experts Group formed by the International Standards Organization (ISO) works to develop and set standards for digital compression of full-motion video. The group's name has been applied to a family of standards that have become accepted for digital audio and video compression. The MPEG standard which uses lossy compression offers excellent quality in a relatively small file size.

Uncompressed video files sizes are huge, MPEG-1 the first of the family of standards, made video distribution possible and was commonly used for video compact discs, however it could only compress progressive scan images. Along came MPEG-2, capable of compressing interlaced images and five channel surround sound audio, quickly becoming the standard for DVD and digital TV broadcasting. With the explosive growth of the Internet and mobile communications came streaming media and the more efficient MPEG-4. The standard was designed for versatility, with separately selectable elements such as video, audio, data and text - scalable to suit low or high bandwidth connections.

Multicast

Multicasting refers to a means of communicating data between a single sender and multiple recipients on a network. The process makes efficient use of bandwidth, because the sender has to generate only a single data stream that gets copied over to its intended recipients as and when required.

Multiplex

Multiplex (or many in one) allows you to split an image into several panels on a single screen or in communications to group two or more signals over a common channel.

Must Carry

The term is used to describe the legal obligation of a cable company (or operator) to carry selected channels available on broadcast terrestrial networks that they may not otherwise have natively included in their line up.

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N

NICAM

Near Instantaneous Companded Audio Multiplex is an early form of lossy audio compression developed by the BBC that enables transmission of digital stereo sound when broadcasting analog TV.

NTSC

The National Television System Committee names an analog television system originating in North America and used in various countries that operate with a 60 Hz power grid. NTSC uses a 60 Hz vertical frequency signal and interlacing to produce video with a rate of 30 frames per second, an effective screen resolution of 720 x 480 pixels and a 4:3 aspect ratio.

NVOD

Near Video on Demand refers to a service where programme's repeatedly start at timed intervals. The programme schedule actually runs on multiple channels, but with staggered start times, giving the impression of video on demand.

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O

OFDM

Orthogonal Frequency Division Multiplexing describes a method for transmitting large volumes of digital data quickly and reliably.

Frequency Division Multiplexing refers to a means by which to simultaneously transfer multiple signals over a single transmission path. OFDM works by splitting a single signal into multiple sub-signals with corresponding but independent sub-carriers, which are transmitted simultaneously at slightly different frequencies. Noise or interference between signals near to each other in frequency is kept to a minimum by design. It's the orthogonal or distribution pattern of independent sub-carriers that is key to reliability. To put it simply it's a case of not putting all your eggs (data) in one basket (carrier).

High data carrying capacity and resistance to interference makes the technique particularly suitable for broadband applications such as digital TV and audio broadcasting.

OLED

Organic Light Emitting Diode describes an LED that generates light in a film of organic compounds. A considerable benefit of OLED displays over traditional LCD's is that OLED's do not require separate backlighting to function and can therefore be much thinner than an LCD panel. Although OLED displays can be more effectively manufactured than LCD or plasma displays, degradation of OLED materials has limited their use.

Optical Fibre

A thin strand of glass designed for the transmission of light pulses in optical information networks. Although a single glass strand is normally no thicker than a human hair, it is capable of transmitting trillions of bits of information per second over long distances with very low error rates.

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P

Packet Switching

Packet switching is an efficient way to deliver data over a network. Data is split into small chunks or packets containing all the information necessary for delivery. Each packet is then sent off to its destination by the best available route. Once all the packets forming a message arrive at their destination, they are assembled back into the original message. All of the content or information on the internet is routed around using packet switching.

PAL

Phase Alternation Line is an analog television display standard originating in Western Europe and used in various countries that operate with a 50 Hz power grid. PAL uses a 50 Hz vertical frequency signal and interlacing to produce video with a rate of 25 frames per second, an effective screen resolution of 720 x 576 pixels and a 4:3 aspect ratio.

PCMCIA

Personal Computer Memory Card International Association is an international standards body and trade association that establishes standards for Integrated Circuit cards and promotes interoperability among mobile computers, digital cameras, cable TV, set-top boxes and such like. PCMCIA is most notably associated with the PC Card commonly used with portable computers.

PCTV

Personal Computer Television is integration of TV with the PC, blending all the functionality of computing with the various features of television. A PC can become TV enabled with the simple addition of a plug in TV device.

Pillarbox Mode

Pillarboxing is a method of presenting traditional (4:3 aspect ratio) images on a widescreen television while preserving the aspect ratio of the original video content. The picture is scaled to fit the available height of the television screen leaving space to the left and right of the picture which is displayed as vertical black bars.

Pixel

Pixel is a contraction of the words ‘picture’ and ‘element’. Image quality is related to the number of pixels that make up an image. Standard digital TV pixels or dots are rectangular in shape, while HDTV pixels are squarer and significantly smaller in size. This allows high definition pictures to contain many more horizontal and vertical coloured dots than standard definition pictures occupying the same overall space.

Pixel Response Time

The amount of time it takes for a single pixel in a video display to switch from active to non-active; measured in milliseconds (ms). If a display’s response time is too slow, visible irregularities may appear on fast moving screen objects. Pixel response time is an important performance spec for all types of digital flat panels, look for a response time of 8 ms or less.

Podcast

Podcast is a term derived from a combination of the words ‘iPod’ and ‘broadcasting’. A podcast is a multimedia broadcast (that virtually anyone can produce) hosted on a website and made available for downloading to portable media players or personal computers. Podcast feeds include a feature known as RSS that allows the content to be automatically updated when subscribers sign up for the podcast.

PVR

A Personal Video Recorder or Digital Video Recorder (DVR) records video in digital format. Digital video recorders have all of the functionality of video cassette recorders, but have the ability to jump to any part of the recording without having to rewind or fast forward.

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Q

QAM

Quadrature Amplitude Modulation is an efficient way of transferring binary data over cable and is the signal modulation system used for digital cable TV in the United States.

QoS

Quality of Service is the ability to control characteristics of a network or infrastructure to deliver traffic with minimum delay and maximum availability.

QuickTime

A multimedia framework developed by Apple Computer that provides powerful tools for multimedia streaming and playback across a range of hardware platforms. In order to play QuickTime files you will need the Quick Time Player.

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R

RealAudio

RealAudio uses a proprietary streaming audio format that produces smaller files than can be achieved with the MP3 format but requires the RealPlayer to hear them.

Resolution

A screen's resolution is usually described by its width and height in pixels. The number of pixels displayed on your screen determines the level of image detail, more pixels equal higher resolution and sharper images.

RF

Radio Frequency is the rate of oscillation that corresponds to the frequency of alternating electrical current signals used to produce and detect radio waves.

RSS

Really Simple Syndication or Rich Site Summary is a method of sharing and broadcasting website content such as news, podcasts or any other material that is frequently updated.

Rx

Receiver. A device used to single out and convert electronic signals into a format for voice, video or data.

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S

Scart

A Scart plug is a European multimedia connector that is rectangular in shape with a distinctive slant at one end of its metal surround. With up to 21 pins, it is able to transfer various signals including component/composite video and stereo audio through a single cable.

SDTV

Standard Definition Television transmissions provide up to 576-line resolution in either interlaced or progressive scanned formats. Progressive scanning displays all of the lines of an image sequentially in a single pass while interlacing requires two separate passes alternating between odd and even lines to produce an image. Although SDTV provides picture quality similar to DVD, it does not reach the quality and resolution of high definition television.

SECAM

Sequential Couleur Avec Memoire is an analog television display standard originating in France and used mainly in Eastern Europe, the Soviet Union and parts of Africa. Operating characteristics are similar to the PAL TV standard, but the underlying technology is different.

Sideloading

The term refers to a specific form of downloading. Downloading is normally though of as being the transfer of data from a central location to a remote device, such as from a web server to a personal computer. Sideloading refers to the transfer of data between local devices, such as your computer to your mobile phone.

SMATV

A Satellite Master Antenna Television System uses one central antenna to pick up broadcast or satellite signals and serves them to a concentration of TV sets. Used by hotels, apartment blocks and such like.

Startover TV

Startover is a feature that allows viewers to restart a TV program already in progress. Since it is an on demand feature, no recording devices or forethought are required by the user.

Streaming

Streaming media or progressive downloading refers to the process whereby you can start to play a digital media file before it is completely downloaded. Unlike a typical download, the streamed file does not normally remain on the recipients machine.

S-Video

Separate-Video describes video transfer using a four-pin mini-DIN connector, where the brightness and colour signals are carried as two separate streams. Image quality is better than that of single stream composite video, but inferior to that of triple stream component video.

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T

TDtv

Terrestrial Digital Television describes a technology that allows mobile phone operators to exploit their existing network infrastructure and bandwidth to transmit low cost high quality multi channel mobile TV and multimedia services to mobile devices.

Technically speaking, TDtv is a UMTS TD-CDMA 3GPP MBMS technology.

Terrestrial TV

Digital or analog TV received through a normal aerial.

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U

UHF

Ultra High Frequency and Very High Frequency (VHF) are the most commonly used frequency bands for transmission of TV signals. Mobile phones also transmit and receive within the UHF spectrum.

UMTS

Universal Mobile Telecommunications System is a 3G mobile phone technology offering global roaming with an enhanced range of multimedia and personalised services at speeds of up to 2Mbps.

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V

VHF

Very High Frequency refers to the radio wave frequency range commonly used to transmit Television and FM Radio signals.

VOD

Video on Demand is a service that enables viewers to watch TV programmes or films whenever they choose to.

VoIP

Voice over Internet Protocol is the technology used to transmit voice calls over a data network rather than traditional telephone lines.

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W

WAN

Wide Area Network refers to a network spanning a wide geographical area. Large organisations typically use a WAN to connect branches which may be in different regions or even countries. The largest WAN is the Internet.

WAV

Wave Form Audio developed by Microsoft and IBM is used extensively on windows PCs. WAV files produce extremely high sound quality but use up to ten times more space than MP3s. Audio files ripped from CD are usually converted to wave files by default.

Webcasting

Webcasting is a contraction of the words ‘web’ and ‘broadcast’. A webcast is an audio or video transmission over the Internet using streaming media technology.

WiFi

Wireless Fidelity is the means by which portable devices can connect to the Internet wirelessly over short distances of approximately 30 metres.

WiMAx

Worldwide Interoperability for Microwave Access is a technology designed to provide high speed wireless internet access over relatively long distances. Whereas WiFi provides wireless internet access over distances of tens of meters, WiMAx provides for a range in tens of kilometres.

WLAN

Wireless Local Area Network describes a local network that works exclusively without wires.

WLL

Wireless Local Loop is a system that connects wireless users to a physical network using wireless communications.

WMA

Windows Media Audio is a sound file format developed by Microsoft. WMA offers near CD quality sound but at half the size of a comparable MP3 file.

WWW

The World Wide Web is the graphical front end of the Internet.

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X

xDSL

General Digital Subscriber Line refers to all types of DSL, DSL's are used to link the home or office to a local telephone exchange.

XviD

XviD is an open source digital video compression format based on MPEG-4 technology that is similar to DivX, but regarded by many to offer superior performance.

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Z

Zoom Mode

Zoom Mode scales a 4:3 aspect ratio picture to fit a 16:9 aspect ratio widescreen.

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