TV & Radio Glossary

The TV & Radio Glossary at

ASTRA Digital Radio. Transmission system used by ASTRA in order to broadcast twelve stereo radio programmes in hi-fi quality on only one sound subcarrier of a satellite TV transponder.
Automatic Frequency Control (AFC)
Automatic Frequency Control. Electronic circuit that connects the undesirably deviations from a selected frequency in the receiver, in order to stabilize reception of a channel.
Usually a reference to the receiver type but means that the signal is sent on an Analogue wave.
Aspect Ratio
Aspect Ratio, is t he relationship between the width and height of a television screen that defines its shape. A standard TV set has an aspect ratio of 4:3, i.e. four units wide by three units high. So, for example, if the screen is 24 inches wide it will be 18 inches high. 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 in 16:9 format.
This is a CAM which emulates S.E.C.A.’s  Mediaguard system
System currently comprising 10 satellites (ASTRA 1A to 1H) at 19.2° East, and ASTRA 2A at 28.2° East. (Societe Europenne des Satellites) based in Betzdorf, Luxembourg.
Sound signal. That part of a TV or radio transmission that is heard.
Audio Bandwidth
Term used for the sum total (range) of frequencies contained within a specific band.
Audio Description
Audio Description, is spoken commentary 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.
Audio Visual (AV)
Connections intended to connect or activate audio-visual (audio and/or video) equipment. For instance, the AV connection between the receiver and the TV set is usually brought about by means of a Scart cable, as this provides better quality than using antenna cable.
Azimuth and Elevation (AZ-EL)
Mounting system for parabolic dish antenna that can be adjusted in two axes – azimuth and elevation.
Azimuth Elevation
The satellite dishes angle to the satellite, an Az/El mount is used on a dish to set it’s angle to the satellite.
A band is a range of frequencies in a range between two end points determined by general consent eg VHF, MW, LW and SW.
A range of frequencies together making up a particular band.
The radiation from a satellite transponder. This may have a circular, elliptical or other shape, when looked at in diameter. The area, where this beam of radiation intersects with the Earth’s surface is the reception area, also known as the footprint. The shape of the reception area depends on the elevation angle of the satellite as well as on the size of the broadcast angle of the transmitter antenna.
Beta Digital
An encryption system and  variant of Irdeto owned by Mindport.
In computer sciences, the smallest elemental unit of data. A bit exists in only one of two possible states “Zero (or On)” or “One (or Off)”. By adding together a number of bits you can create a digital “word”, known as a byte.
A group of television channels owned by the same company, e.g. British Sky Broadcasting, TPS, Canal Digital, Viasat, Canal+, Sky Italia and Premiere.
Branch Connector
Passive construction element in a distribution system designed to divert part of the signals from the trunk line. The level of the branched-off signal is dependent on the branch damping of the branch connector.
Broadband refers to a system or circuit that can carry signals over a wide range of frequencies or bandwidth. The wider the bandwidth, the more information that can be carried. For example, broadband internet gives you a high-speed connection suitable for downloading video and audio, etc.
In computer sciences, a group or packet of 8, 16, 32 etc, bits used in data transmission. Larger units are Kilobytes (1024 bytes) and Megabytes (1024 Kilobytes each). This deviates from the expected metric progression (1,000, 1,000,000 etc) because of the binary structure of computer data. Thus one Kilobyte is actually 210.
Clark Belt
Named after Arthur C. Clark, the Belt is situated 38,000 Kilometres above the Earth. This is where all the geostationary satellites are positioned either east or west. Satellite dishes face south in the Northern Hemisphere, and north in the Southern Hemisphere.
Common Interface (CI)
This is the empty slot on the receiver, into which a Conditional access Module (CAM), is inserted.
Composite Video
Composite video is the format of an analogue television signal before it is modulated onto an RF carrier. It is usually in a standard format such as NTSC, PAL or SECAM. It is a composite of three source signals called Y, U and V (together referred to as YUV). Y represents the brightness or luminance of the picture and includes synchronizing pulses, so that by itself it could be displayed as a monochrome picture. U and V between them carry the colour information. They are first mixed with two orthogonal phases of a colour carrier signal to form a signal called the chrominance. Y and UV are then added together. Since Y is a baseband signal and UV has been mixed with a carrier, this addition is equivalent to frequency-division multiplexing.
Conditional Access Module (CAM)
A removable decoding module used in digital satellite and digital terrestrial receivers, there are many types of CAMs on the market, including programmable types like the Matrix and Joker CAMs.
Conditional Access System (CAS)
Encryption, there are many variants on the market, some of those used in Europe are: Videoguard, Irdeto, Viaccess, Conax, Seca, Cryptoworks, Mediaguard and Nagravision.
Encryption System owned by Telenor and Canal Digital, used in the Scandinavian countries, Bulgaria and by a hanfull of other broadcasters.
Cathode Ray Tube (CRT)
Cathode Ray Tube, as in the standard type of large-bodied TV set.
An encryption system owned by Philips.
Digital Audio Broadcasting (DAB), also known as Eureka 147, is a digital radio technology for broadcasting radio stations, used in several countries, particularly in Europe. As of 2006, approximately 1,000 stations worldwide broadcast in the DAB format.
DAB+ is based on the original DAB standard but uses a more efficient audio codec. Whereas DAB uses MPEG Audio Layer II (better known as MP2), DAB+ uses HE-AAC v2 (better known as MP4 or AAC+). This allows equivalent or better subjective audio quality to be broadcast at lower bit rates.
Digital cable, digital TV received via a cable connection.
A decoder, is a device that unscrambles digital signals and turns them back into sound and pictures. It may come as a set-top box, or be built into a TV set or PVR.
Data transfer using numbers = allows compression because numbers can be sent faster than the data is needed – thus allowing several channels to be sent at the same time.
Digital light processing (DLP)
Digital light processing (DLP), is a technology used in rear-projection flat-panel TV screens.
Digital Video Broadcasting (DVB)
Digital Video Broadcasting (DVB), the European standard for digital TV technology.
Digital Satellite Equipment Control, often thought of as a Eutelsat system it was actually STAB Italia that designed the protocol for DiSEqC and have further developed it with USALS.
Dish/Parabolic Antenna
Reflects the signal from a satellite towards the LNB.
Digital On-screen Graphics (DOGs)
Digital On-screen Graphics (DOGs), are channel identifications or logos, usually seen in the top left-hand corner of the TV screen.
Digital satellite: digital TV received via a satellite dish.
Digital terrestrial television: digital TV received via a standard aerial.
Digital Visual Interface (DVI)
Digital Visual Interface (DVI), a digital connection for high-quality video, suitable for HDTV.
Digital Video Recorder (DVR)
Digital Video Recorder (DVR), more often known as a PVR (personal video recorder), this records TV programmes digitally on to a hard disk (like saving information on a computer).
Rewritable Memory device found inside Receivers, CAMs, and Cards.
Electronic Programme Guide (EPG)
Electronic Programme Guide (EPG), on-screen listings of what’s on TV now, and often for a number of days or weeks ahead, depending on which digital service you have.
Usually referring to a built-in encryption like Videoguard in Sky Digital receivers.
Scrambling of a signal usually for the purposes of selling a service, or restricting a signal to a certain country for copyright reasons.
An Ensemble, is a digital radio term for a single frequency that contains a number of radio channels also known as a Multiplex.
Forward Error Correction (FEC)
Forward Error Correction (FEC), is often given as ¾ for example in this case the 4th bit of data corrects any errors in the first 3 bits.
Feed Horn
Front section of a modern LNB, is a wave guide which bounces the High frequency signals down to the LNB polariser.
A reprogrammable memory used in Cards CAMs and Satellite receivers.
Freesat is a free-to-air digital satellite platform run as a joint venture by the BBC and ITV. Website:
Freesat from Sky
Free satellite TV service, where you pay for the equipment, there is no subscription to receive free-to-air and free-to-view channels.
Free-To-Air (FTA)
Free-To-Air services, are not encrypted and require no card or subscription for viewing. All of the BBC’s domestic TV and radio services are FTA.
Free To View (FTV)
Free To View channels do not require a subscription, the channels are however encrypted and require a Sky freesat card. These cards will give you access to Channel Four, Sky Three, Five, Five Life and Five US.
Freeview is a free-to-air digital terrestrial platform available through ground based (terrestrial) transmitters in the United Kingdom. Website:
Full HD 1080p
The number “1080” represents 1,080 lines of vertical resolution (1080 horizontal scan lines), while the letter p stands for progressive scan (meaning the image is not interlaced). 1080p can be referred to as full HD or full high definition to differentiate it from other HDTV video modes.
Geostationary Satellites
These satellites appear from earth to be stationary because they orbit the earth above the equator and their distance and speed means that they take 24 hours to circumnavigate the planet which is the same time as it takes for the earth to rotate once. They are sometimes referred to as TV Satellite satellites.
Gigahertz (Ghz)
1 Ghz = 1000,000,000 Cycles per second.
High-Definition Multimedia Interface (HDMI)
High-Definition Multimedia Interface (HDMI) is a compact audio/video connector interface for transmitting uncompressed digital streams. HDMI connects digital audio/video sources such as set-top boxes, Blu-ray Disc players, personal computers, video game consoles, and AV receivers to compatible digital audio devices, computer monitors, and digital televisions.
HD Ready
HD ready concerns the abilities of television receivers to display high-definition pictures. The term has had official use in Europe since January 2005 when, EICTA (European Information, Communications and Consumer Electronics Technology Industry Associations) announced the requirements for the label. HD Ready refers to any display that is capable of accepting and displaying a high-definition signal at either 720p, 1080i or 1080p using a component video or digital input, and does not have a built-in HD-capable tuner.
High Definition Television (HDTV)
High-definition television (HDTV) is a digital television broadcasting system with higher resolution than traditional television systems (standard-definition TV, or SDTV). HDTV is digitally broadcast because digital television (DTV) requires less bandwidth if sufficient video compression is used.
An encryption system owned by Mindport.
Integrated Digital Television (IDTV)
Integrated Digital Television (IDTV), is a TV set with a built-in digital TV receiver that can receive Freeview or Freesat, or both without a separate set-top box.
Interactive TV
Features added to TV programmes that let you get extra information, join in with things such as quizzes, or make choices about what to view. You access interactive features via the red button on the remote control.
KiloHertz (Khz)
KiloHertz (Khz), 1 Khz = 1000 cycles per second.
Liquid Crystal Display (LCD)
Liquid Crystal Display (LCD), is a technology that displays a picture on a flat-panel screen. It is particularly suitable for large-size TV screens and is good for HD TV.
Low Noise Block (LNB)
The LNB down converts the High frequency signals from a satellite to a range which can be “seen” by the satellites tuner using a Local Oscillator – Typically an LNB will have two of these a “Universal” LNB will have a Local Oscillator set at 9.75 Ghz and another at 10.6 Ghz (this higher one is activated by the receiver sending a 22Khz Tone.
Low Noise Block Feed (LNBF)
The LNBF down converts the High frequency signals from a satellite to a range which can be “seen” by the satellites tuner using a Local Oscillator – Typically an LNB will have two of these a “Universal” LNB will have a Local Oscillator set at 9.75 Ghz and another at 10.6 Ghz (this higher one is activated by the receiver sending a 22Khz Tone.
LNB Loop
This allows a second receiver to be connected to a dish thus expanding the potential – the second receiver could be an analogue receiver connected to a digital receiver – or a second digital receiver – in the case of the later being a second receiver which has USALS BOTH receivers can control the dish position, but watch out always leave the second receiver on a vertical channel otherwise the first receiver may not be able to select a vertical channel when it is on.
Nagra France develops and markets the Mediaguard conditional access system.
Multiplex (MUX)
A Multiplex (MUX), is single broadcast frequency that contains a number of different TV or radio channels. For example, six multiplexes carry all the TV channels and radio networks on Freeview and Top Up TV Anytime.
Nagravision is a market leader in the field of conditional access for digital TV and broadband Internet. Leading operators are equipped with its technology which ensures secure access to their services via more than 35 million decoders (analogue and digital).
Null Modem Cable
A Null Modem Cable, is a crossed serial lead with 2 female ends used for two PC’s or two receivers or one PC and one receiver to talk to another, used for upgrading a satellite receiver with new software. Pin wiring on a serial null modem cable is as follows Pins 1-1, 2-3, 3-2, 4-6, 5-5, 6-4, 7-8, 8-7, 9-9.
Offset Dish
Most common dish type the dish, the signal is reflected down into the LNB.
Pay Per View (PPV)
Many operators have Pay Per View (PPV) channels for films or special events, the customer only pays for the programmes watched.
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 a hard disk (like saving information on a computer), instead of on video tape or DVD. It has an electronic programme guide (EPG) built in, and allows you to pause and ‘rewind’ a programme while you are watching it.
Programmable Integrated Circuit = a small computer used in satellite receivers CAMs and Cards.
PID (Packet Identify)
Bits of data joined together, every digital TV channel has a Video, Audio and PCR PID.
Short for picture element: a single dot on a TV screen (or computer screen or digital photo). Thousands of pixels make up the picture, and the more pixels the better the picture. High-definition TV has up to four times as many pixels as standard-definition TV.
Plasma is 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.
A Platform in broadcasting, is a system for delivering TV and radio services. For example, digital TV is delivered mainly on terrestrial, satellite and cable platforms.
Polar Mount
Mount which usually fits on a pole and gives the dish the ability to pivot on a line which is parallel to the two poles of the planet.
A polariser is part of an LNB, it selects vertical or horizontal polarization of the signal – Circular left and right hand polarization of signals is also possible though rare – usually Polarisation is selected by different voltages sent by the receiver 13Volts = vertical 17v = Horizontal.
Power Vu
Power Vu, is an encryption system owned by Scientific Atlantic, used to distribute channels to cable operators and TV service providers.
Prime Focus Dish
A Prime Focus Dish, is one that points directly at the satellite and has a center feed.
Programme Type Code (PTY)
Programme Type Code (PTY), identifies a particular type of broadcast (Rock, Jazz, Sports, Talk, News, Classical).
Receiver, Satellite receiver or Tuner, used to receive TV and radio transmissions from satellites.
Radio frequency, an RF connector is used to feed a TV signal from an aerial to a TV, video recorder, etc.
RGB stands for Red Green and Blue, these are the 3 colours used to display a TV picture.  Using RGB the picture is sent as three separate colours corresponding to the three colours used in a TV to display the picture. A high resolution RGB picture can have a bandwidth of over 10MHz and this is without doubt the best way to send picture information to a TV or display. Component video Component video is comprised of a Y signal (this is the luminance being a mixture of red, green and blue), and two colour difference signals, referred to as either V & U or Cr & Cb respectively. Both require a sync signal to generate the required timing inside the TV so that a viewable picture can be built up. When using a DVD player it may be better to use Y Cr Cb output , as they generate these straight from the digital signals. There are more than a few options for sending the sync signal with RGB. The norm is for 75R terminated signals and 0.7V peak with higher voltage producing a brighter image.
Satellite Dish
A satellite dish is a type of parabolic reflector A parabolic reflector (also known as a parabolic dish or a parabolic mirror) is a reflective device formed in the shape of a paraboloid of revolution. Parabolic reflectors can either collect or distribute energy such as light, sound, or radio waves.
Syndicat des Constructeurs d’Appareils Radiorécepteurs et Téléviseurs (SCART), connector used for combined audio and video connections.
Encryption of a signal, usually a subscription and Smart Card are needed to de-crypt the scrambled signal.
Service Provider
TV Operator/Provider, a company or organisation, which supplies a TV or Radio service or station.
Set Top Box (STB)
A Set Top Box is a receiver.
SID (Station Identification number)
Each station has a different one and is the same on all of its transmitters. Used by car radios to keep playing the same station as you move round the area.
The use of different types of encryption system at the same time.
Smart Card
A device used to act as a key for the CAM, the card is interrogated by the CAM to check if the Card has the rights paid for the service you have selected Subscription Paying for a service, provided by a Service Provider.
Symbolrate (SR)
The carrier on the satellite is made up of a sequence of joined together pulses to make a continuous signal. Each pulse is a symbol. According to the modulation method each symbol represents 1, 2 or 3 etc bits of transmission rate data. As a general rule if you have bandwidth to spare, then use a lower order modulation or a low rate FEC (like 1/2 or 2/3) to spread the signal out. If you have power to spare then use a higher order modulation and/or higher rate FEC (like 3/4 or 7/8). Ideally you want to use all of both the available bandwidth and power simultaneously. If you use larger reception dishes you will always be able to increase the system capacity. If you are doing a point to point link it is worth using larger dishes. If you have thousands of receive dishes then the aggregate cost of these is significant and you will want to allow smaller sizes even though this reduces system capacity and increases space segment costs.
T & K Mount
Type of Mount named after the shape of the mount helps to mount a Pole perfectly vertical.
Terrestrial TV that is broadcast and received via an aerial, such as Freeview in the United Kingdom.
A Tuner is part of the part of the receiver.
Ultra High Frequency.
UHF Loop
Input & output to insert the Satellite TV signal into the normal TV Band.
USALS (Universal Satellite Equipment Control)
USALS (Universal Satellite Equipment Control), is an advancement of DiSEqC 1.2 which allows the receiver to communicate it’s operating position with the Motor Mount which must also be USALS compatible. This enhancement makes fitting a motorized DiSEqC 1.2 system very easy, as you only need to enter the Longitude and Latitude of your current position in order for the mount to calculate where every satellite is situated.
Universal LNB
This type of LNB has a Local Oscillator set at 9.75 and another set at 10.60 the higher one is instigated when the receiver sends a 22Khz Tone.
Encryption system owned by France Telecom, there are three main types Viaccess 1, Viaccess 2 and Viaccess 3,
Conditional Access System (CAS), owned by NDS and used by Sky Digital for encrypting channels on the Sky Digital platform. Videoguard is also used by Sky Italia and Viasat.
Video On Demand (VOD)
Video On Demand (VOD), a service that allows you to receive and watch selected TV programmes when you want, rather than when they are broadcast.
TV pictures with an aspect ratio of 16:9 that gives a ‘letterbox’ shape like that of a cinema screen. The programmes on most of the major TV channels are now in widescreen format.
YouView is an Internet TV service in the UK. Formally launched on 4 July 2012, it is a partnership between three telecommunications operators and four broadcasters (BBC, ITV, Channel 4 and Channel 5). YouView provides access to Freeview television and TV on demand (catch-up TV) services via a ‘hybrid’ set-top box, connected with a broadband connection and a television antenna. There is no contract and no subscription for accessing catch-up and Freeview content; there is just a one-off payment