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Satellite TV Receivers
Glossary
Glossary
A-C:
Analogue
The world as we have experienced it is an analogue world. Any kind of information (e.g.
Sound Speech, Pictures) is transmitted in continuous waveforms which the human senses are
able to receive and to interpretate.
Auto search
IRD feature that automatically locates and stores all satellite channels into its memory.
Astra
Operated by the Socitete Europeenne des Satellite (Luxembourg), the Astra Satellite family
(1A-E) provides about 56 transponder for analogue and digital direct-to-home transmission
channels of Audio and TV-programmes in Europe.
API
Abbreviation for Application Program Interface.
ATM
Abbreviation for Asyncronous Transfer Mode
Bandwidth (broad-, narrow band)
The speed of data transmission depends on the available bandwidth of the transmission
channel. Narrow band channels provide data transfer rates of 100 kbit/s (NA.MHz) whereas
broadband channels allow transfer of >1 Mbit/s (NA.MHz).
Back channel
To enable interactive and Pay-TV services, a direct communication channel between the
broadcaster or service provider and the consumer is needed. Normally this "Back"
or "Return channel" is realised via the normal telephone line.
BAT
Abbreviation for Bouquet Association Table
Bit/byte
One bit is the smallest discrete element in a binary system. Eight bits comprise one byte.
Bitrate
The rate (in Mbit/s) for transmission of serial digital information
Bouquet
A collection of services marketed as a single entity.
Broadcaster
An organisation which assembles a sequence of events or programmes to be delivered to the
viewer based upon a schedule.
CA
Conditional Access system. A system to control subscriber access to services, programmes
and events e.g. Nagra, Viaccess, Irdeto, Seca.
CA module
A device in Mediamaster for decoding of scrambled signals.
Carrier
A signal modulated to carry information.
CAT
Abbreviation for Conditional Access Table.
C-Band
The 3,7 to 4,2 GHz range in the frequency band.
Coaxial Cable
A type of cable used to transport high frequency signals e.g. from the LNB to the
satellite receiver.
CD-ROM
Compact Disc- Read Only Memory. The CD-ROM is an optical storage device, which is not
erasable. The storage capacity of a CD-ROM is 650 Mbytes.
Common Interface
Describes a hard and software architecture for Conditional Access Systems whereby the
generic "host" set-top-box is not dedicated to one particular encryption system.
Consumers use detachable modules, which allow them to receive encrypted services they pay
subscription fee for. The interface between host set top box and module is standardised
(PCMCIA-Interface) so that the same set top box can be used to handle a variety of
encryption systems.
Conditional Access (CA)
A system for scrambling and encryption signals in order to deny access to programmes for
those viewers who have not paid subscription fees for these programmes (e.g. Videoguard,
Eurocrypt).
CRC
Abbreviation for Cyclic Redundancy Check
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Glossary, D-E
DAVIC
The Digital Audio Video Council, an international group which met for the first time in
1994, is set up to define the interfaces and protocols necessary to support delivery of
international digital video services.
Decoder
A device that restores a signal to its original form after it has been encoded.
Demodulator
A device that extracts digital information from transmitted carrier waves.
Digital
Any kind of analogue information (speech, pictures, text, etc.) can be scanned and
transformed into binary digits.
DAB
Digital Audio Broadcasting is a digital transmission system for radio broadcasting, using
dedicated receivers. In addition to audio data (voice and music) DAB allows as well to
transmit video and information data at low data transfer rates.
Digital compression
A way of reducing the number of bits in a digital signal by using mathematical algorithms
to eliminate redundant information thereby reducing the space the signal occupies when
being transmitted or recorded.
DVB
Digital Video Broadcasting group was created to establish a technical framework for the
introduction of digital broadcasting systems to suit the whole range of delivery
mechanisms, including cable, satellite, terrestrial and MMDS. DVB has already developed a
coherent set of methods to bring digital television to home.
DBS
Direct Broadcasting satellite is an american transmission system based on high-powered
Ku-band satellites (120-200 watts per transponder). The signals can be received using a
small 18 inch dish. Currently there are four DBS-Services in operation in the US
(Primestar, DirecTV/USSB and EchoStar).
DTH
Direct-To-Home. Used to denote satellite TV signals received by a single household via an
individual dish installation.
Dish
The dish collects, reflects and focuses the satellite signal into the LNB.
Downconverter
A device that reduces the high-frequency signal to a lower, intermediate range. The three
types of downconversion are signal, dual and block downconversion.
Downlink
Term used to describe the retransmitting of signals from a satellite back to Earth.
Download
The download function enables service providers to update the system software of their Set
Top Boxes via their transmission channels.
EBU
Abbreviation for European Broadcasting Union
ECM
Entitlement Control Messages. Are private Conditional Access information which maintain
the ordered authorization.
EIT
Abbreviation for Event Information Table
E-mail
A system for transmitting messages or information through an electronic communication
network.
Encoder
A device that encodes the signal before transmission.
EMM
Entitlement Management Messages. Are private Conditional Access information which specify
the authorization levels or the services of specific decoders. They may be addressed to
individual decoder or groups of decoders.
EPG
A software that enable viewers to navigate easily amongst the large number of channels
provided by digital technology in order to select the service they desire.
ETS
Abbreviation for European Telecommunication Standard
ETSI
Abbreviation for European Telecommunication Standard Institute
Error Correction Mode
Due to the high compression factors used in MPEG decoding of digital signals, Error
Correction Modes become necessary, to avoid any significant loss of bit information during
signal transmission. Commonly applied are Reed-Solomon Codes. The efficiency of error
correction modes are defined by the so called bit error rate (BER), which gives the
quotient received bits to the total number of transmitted bits in a specified time period.
Event
A grouping of elementary broadcast data streams with a defined start and end time
belonging to a common service, e.g. first half of a football match, News Flash, a talk
show.
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Glossary, F-L
FEC
Abbreviation for Forward Error Correction. Correction to a certain extent, of faulty bits
in the received signal.
Flash memory
A memory module used for permanent data-storing.
Footprint
The geographic area toward which a satellite directs its signal. Within the footprint of a
satellite the reception of the satellite signals is possible with high quality using a
dish of specified size.
Frequency
The property of a signal measured in cycles per second (=Hz).
Geostationary
Fixed orbit, approximately 36.000 km above the Earth´s equator. Satellites parked in this
orbit travel at the same speed as the rotation of the Earth.
Gigahertz
One billion cycles per second (1.000.000.000 Hz/s). Signals above one gigahertz are called
microwaves.
HDTV
Abbreviation for High Definition Television.
Hertz
Cycles per second
Homeshopping
Home- or Teleshopping enables consumers to chose and order goods directly from their home,
using their PC or their TV-set together with a Set Top Box.
Homebanking
Homebanking enables consumers to manage all banking directly from their home, using their
PC or their TV-set together with a Set Top Box.
IEC
Abbreviation for International Electrotechnical Commission.
IRD
Abbreviation for Integrated Receiver Decoder. A Set Top Box receiver with a built in
descrambler for decoding pay-TV services.
Integrated Services Digital Network (ISDN)
Series of CCITT Recommendations related to the transmission of voices and data down the
same line.
ISO
Abbreviation for International Organisation for Standardisation
ITV
Interactive Television Based on a backchannel interactive TV enables the consumer e.g. to
select his individual TV programme at any time or to take part in game shows although
being at home. The acceptance of interactive TV is presently tested in various pilot runs
all over the world.
Interface
An interface is a connection between electronic devices. Examples: SCART, RS250, SCSI
LNB
Low Noise Block Converter Usually mounted at the focal point of the dish and used to
amplify and convert satellite signals into frequencies sent to the receiver.
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Glossary, M-O
MCPC
Multiple Channel Per Carrier.
Megahertz
Millions of cycles per second.
MMDS
Microwave Multichannel Distribution System. A distribution service for TV signals using
microwave transmissions. Also called multichannel video distribution system (MVDS). In the
US, it is called "wireless cable".
Modem
Modulator/Demodulator. A device for converting digital data to audio tone and (vice versa)
for transmisson on an analogue channel.
Modulation
(QAM, QPSK, OFDM)
MPEG
Motion Picture Expert Group Body established by the International Standards Organisation
to provide the basis for a picture coding and compression system. MPEG first designed a
standard - MPEG -1 - for bitrates of around 1.2 Mbit/s, primarily for carring VHS-quality
video on compact disc based multimedia systems. MPEG-2 is a video compression standard
being developed for bitrates from 3 - 15 Mbit/s.
MPEG-2
MPEG-2 is a video compression standard being developed for bitrates from 3 - 15 Mbit/s.
Multiplex
A stream of all the digital data carrying one or more services within a single physical
channel.
Network
A collection of MPEG-2 Transport Stream multiplexes transmitted on a single delivery
system, e.g. all digital channels on a specific cable system.
NTSC
The colour TV system established by the US National Television Standards Committee which
is used in North America, Japan and their dependents. NTSC produces interlaced 525 line 30
frame/s pictures.
NVOD
Near Video On Demand. Term properly describing movie service, but now generally referring
to all types of near-on-demand services where viewers are able to order and see a given
program of an individual basis at a given time interval.
OFDM
Orthogonal Frequency Division Multiplexing
Online Services
Online Services are commercial networks providing information in a certain structure to
their customers. They also offer communication tools like E-Mail, Chat-Lines a.s.o. The
most popular commercial Online Services are America Online, CompuServe and Microsoft
Network.
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Glossary, P-R
PAL
Phase Alternation Line
A colour TV system, developed in Germany, which is used in most of Europe, Africa,
Australia, and South America. Pal produces interlaced 625 line, 25 frame/s pictures.
PALplus
PALplus is the name of a strategy group formed in 1989 to develop an enhanced terrestrial
transmission system compatible with conventional PAL. The group, made up of German,
Austrain, Swiss and British broadcasters as well Philips, Thomson, Grundig, Nokia, Sony
and Samsung, set itself the task of enhancing the PAL signal by developing the 16:9
letterbox format, increasing the useable luminance bandwidth, reducing cross-colour
artifacts, working on echo cancellation and improving sound.
Pay TV
Encrypted TV programmes, which can only be accessed by subscribers, using entitled smard
cards of the broadcasters. Generally Pay TV is distiguished into two categories:
1. Pay per Channel
Customers subscribe on a monthly basis a package of TV-channels.
2. Pay per View
Customers pay for viewing one single movie or e.g. sport event which is selected
individually from the TV channels. The smard card registers the access to the programme in
order to charge the customer for the selected service.
PID
Packet Identifier.
PID is a code used for identifying of the components that forms a particular service in
the transmitted datastream.
Point-to-Multipoint
A connection between a service provider and a number of receivers. (E.g. PPV service)
Point-to-Point
A (temporary) separate connection between a service provider and one receiver. (E.g. VOD
service)
PPV
Pay Per View.
Customers pay for viewing one single movie or e.g. sport event which is selected
individually from the TV channels. The smard card registers the access to the programme in
order to charge the customer for the selected service.
Programme
A concatenation of one or more events under the control of a broadcaster e.g. news show,
entertainment show.
PSI
Abbreviation for Program Specific Information
PSTN
Abbreviation for Public Switched Telephone Network
QAM
Quadrature Amplitude Modulation. Modulation standard used for cable transmission.
QPSK
Quadrature Phase Shift Keying. Modulation standard used for satellite transmission.
RAM
Random Access Memory. A memory used to store temporary data. The data will be lost when
power is swiched off.
RS-250
A serial communication standard used in PC's.
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Glossary, S-V
SAS
Subscriber Authorisation System
The SAS is responsible for generating the actual entitlement messages, following the
specifications of the encryption standard used.
SCART
Connector-standard used for TV/VCR-devices. Also referred to as
"Euro-connector".
SCPC
Abbreviation for Single Channel per Carrier.
Scrambling
Encryption of data to be transmitted for a specific service.
SCSI
Parallell PC connection-standard used for high speed transmission (CD-ROM, Hard Disk,
etc.).
SECA
Abbreviation for Societé Européene de Controle D'Access
SECAM
Sequentiel Couleur a Memoire
The colour TV standard developed in France, also used in Eastern Europe, and parts of the
Middle East and Africa. SECAM produces interlaced 625 line, 25 frames/s picture.
Service
A sequence of programmes under the control of a broadcaster which can be broadcast as part
of a schedule.
Service Information
Service Information data is a part of all the EPG data.
Service provider
A company that collects the contents from a number of program/content providers and
distributes the services to customers.
Set Top Box
A Set Top Box is a device, which enables the owner of analogue TV sets to receive digital
TV signals.
SI
Service Information. Service Information data is a part of all the EPG data.
Smart Card
A credit Card-size card contains updateable magnetic or chip memory, used for accessing
encrypted TV services, e.g. when inserted in the decoder
SMS
Subscriber Management System (other names: CMS,Customer Care and Billing System). The SMS
is a part of a technical chain, referred to as the entitlement control chain. The SMS
contains all customer relevant information and is responsible for keeping track of placed
orders, credit limits, invoicing and payments, as well as the generation of reports and
statistics.
When an order is placed and accepted by the SMS, the system will support all
administrative tasks regarding the customer, e g invoicing, payments and business
reporting.
Transponder
A satellite is divided up in parts called transponders. A transponder is one distribution
channel of the satellite Each transponder can be used for distribution of several
programs.
VOD
Video On Demand
Term properly describing movie service, but now generally referring to all types of
on-demand services where viewers are able to order and see a given program of an
individual basis at the time specified.
To the extent that VOD requires a swithed network architecture, telephone companies are
actively exploring the possibility of using their twisted cupper wire network for video
distribution using ADSL techniques.
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