GlossaryTOP

A  |  B  |  C  |  D  |  E  |  F  |  G  |  H  |  I  |  J  |  K  |  L  |  M  |  N  |  O  |  P  |  Q  |  R  |  S  |  T  |  U  |  V  |  W  |  X  |  Y  |  Z  

A

Aerial cable
Connecting cable between the modulator of the satellite receiver and the TV antenna input, as an alternative if no SCART connector is available.
 
Attenuation
he measure of the weakening of a signal (loss) that occurs as it travels through a device or transmission medium (e.g. radio waves through the atmosphere, an electrical signal through a cable). Attenuation is usually measured in decibels. 
 
AV
See SCART.

B

Band switching
The process of selecting one of two frequency bands (the ‘low band’ or the ‘high band’) for reception of satellite signals.Frequency band switching is implemented in dual-band LNBs by changing the frequency of the local oscillator reference signal that is used to down convert the received signals to IF.
 
Bit Error Rate (BER)
An overall measure of the quality of a received digital bit stream.It is the ratio of the number of information bits that are received in error to the total number of bits received, averaged over a period of time.
 
Bouquet
A collection of digital multimedia services marketed as a single package, often transmitted in a single data stream.
See also Digital Multiplexing.
 
BSS
Broadcasting Satellite Service. Typically used to refer to a range of frequencies intended for direct reception of satellite television and entertainment services.
These frequencies are subject to internationally-agreed regulations that govern their use and are designed to ensure that all countries are able to offer services of this nature.
In Europe, the BSS downlink frequency range is 11.7 – 12.5 GHz

C

CA
Conditional Access. See CAS.
 
CAM
Conditional Access Module.
 
CAS
onditional Access System.  Common name for the decryption system either built (embedded) into the satellite receiver or performed via a CA-module inserted into a receiver’s CI slot (Common Interface). 
CAS systems are normally connected to a smart card reader to allow Pay-TV operators to control subscriber access to .encrypted signals.
 
CI
Common Interface.A standard for using PCMCIA devices to implement different features into a set-top box.Normally 1 or 2 CI slots are available. Example: CAM modules for Conax or Viaccess decoding.
 
C/N
Carrier-to-Noise ratio.A measure of the quality of a modulated carrier at the receiver input.
It is the ratio of the power of the carrier to the power of the noise introduced in the transmission medium, measured within a specified bandwidth (usually the modulated carrier’s bandwidth): It is usually expressed in decibels.
The higher the ratio, the better quality of the received carrier.
 
Channel
A band of radio frequencies assigned for a particular purpose, usually for the establishment of one complete communication link, or a path for an electrical signal. 
This term is often used interchangeably with Transponder, but in general the channel bandwidth is less than the transponder bandwidth.
 
Circular polarization
A circularly-polarised wave, in which the electric field vector, observed in any fixed plane normal to the direction of propagation, rotates with time and traces a circle in the plane of observation. 
Unlike linear polarisation, circular polarisation does not require alignment of earth station and satellite antennas with the polarisation of the radio waves.
 
Clarke belt
The circular orbit at approximately 35,800 km above the equator, where the satellites travel at the same speed as the earth’s rotation (Geostationary Orbit) and thus appear to be stationary to an observer on Earth. Named after Arthur C. Clarke who first postulated the idea of geostationary communication satellites.
 
Coaxial Cable
Connecting cable between i.e.LNB and satellite receiver, for transmission of signals received and for supply of power to LNB unit.
 
Community Reception
The reception of satellite television and entertainment services for distribution to a group of the general public at one location (e.g. in a block of flats), or through a distribution system covering a limited area (e.g. a local cable network). 
The receiving system is usually more complex with a larger antenna than that used for individual (Direct-To-Home) reception.
 
Conax
Digital coding/encryption method. See CAS

D

Data compression/MPEG1/MPEG2/MPEG
Transmission of the present TV standard (625 lines and 50 Hz picture frequency for a PAL signal) requires a digital data amount of 216 Mbit/s.
This would require transmission bandwidths that are not available either terrestrially or via satellite.
Therefore a reduction of the data amount is made through data reduction.In Europe MPEG2 and soon MPEG4 are the universal standard for data compression.
MPEG2 and MPEG4 are extensions of MPEG1. 
 
DCF
Double Channel Filter.
 
Direct-To-Home (DTH)
The process of delivering satellite signals directly to individual households or receiving satellite signals directly in the home via an individual reception system (dish). 
 
DiSEqC
Digital Satellite Equipment Control.
A digital control signal for controlling the DiSEqC-compatible units (typically one or more switches) of the dish over the coaxial cable.
 
DTH
Direct To Home.
Single home installation.
 
DVB
Digital Video Broadcasting.
A digital, universal transmission technique and standard for picture, graphics, sound and text as well as for data of any shape and quality.

E

EPG
Electronic Programme Guide.A graphical user interface generated by a digital satellite receiver and displayed on the user’s television screen.It provides information on the timing and content of television programmes, which is conveyed in the digital signals received from the satellite.Its primary purpose is to help the user to rapidly identify and select programs of interest, but it may also support other interactive services.

F

Footprint
The geographic area over which a satellite antenna receives or directs its signals.
There is often a collection of concentric footprints, each representing a particular satellite EIRP or G/T.
These quantities can be related to the size of the antenna that is needed on the ground to receive or transmit a particular service respectively. 
 
Frequency
Physical quantity indicates the number of cycles per second, measured in Hertz (Hz).
Unit of frequency/designation/cycles per second
1 Hz 1 Hertz 1
1 KHz 1 Kilo Hertz 1,000
1 MHz 1 Mega Hertz 1,000,000
1 GHz 1 Giga Hertz 1,000,000,000
 
Frequency Range
a) Satellite and LNB:
11 GHz range from 10.70-11.70 GHz
12 GHz range from 11.70-12.75 GHz
b) Receiver:
Intermediate frequency or 1 IF: 950-2150 MHz
 
Frequency Reuse
The key characteristic of a cellular network is the ability to re-use frequencies to increase both coverage and capacity.
Adjacent cells must use different frequencies, however there is no problem with two cells sufficiently far apart operating on the same frequency.
The elements that determine frequency reuse are the reuse distance and the reuse factor.
 
FTA
Free To Air

G

Gain (antenna)
A measure of the amplifying or focusing power of an antenna when transmitting to, or receiving from, a particular direction in space.
The gain of an antenna is the ratio of the power radiated (or received) per unit solid angle by the antenna in a given direction to the power radiated (or received) per unit solid angle by an isotropic antenna fed with the same power.
The gain is usually expressed in dB.
 
Geostationary
An object orbiting the Earth at such speed that it appears to remain stationary with respect to the earth’s surface. See also Clarke Belt.
 
Giga
One billion – 1,000,000,000

H

Hertz
The unit used for measuring frequency.Equals number of cycles per second.
See Frequency. 
 
High band
The upper part of the Ku-band downlink frequency range, from 11.7-12.75 GHz.
 
Horizontal Polarization
Type of linear polarization where the electric field is approximately aligned with the local horizontal plane at an on-ground transmission or reception point.
See also frequency reuse

I

IF
Intermediate frequency.
 
Interference
Any undesired signal that tends to interfere with the reception of radio waves.It can be caused by transmissions within the same satellite system, by transmissions within other satellite systems that use the same frequencies, or from ground-based sources. (e.g. point-to-point radio links, car ignition noise, etc.).
 
Intermediate frequency (IF)
The frequency range from the satellite cannot be transmitted via a cable and is therefore converted to the intermediate frequency range from 950 to 2050 MHz by the LNB.
This allows for transmission and processing in the receiver.
 
IRD
Integrated Receiver-Decoder.An indoor device accepting signals from at least one LNB, which recovers the original signal from the signal delivered by the LNB.
It includes a built-in decoder for reception of services that are protected by a Conditional Access system, subject to authorization from the service provider. A plug-in “smart-card” is often used for authorization purposes.
Used to refer to a range of frequencies that are available for use by satellite communication systems at around 30 GHz for the uplink and 20 GHz for the downlink.

J

JPEG
Joint Photographic Experts Group.
The organization behind standards for the compression of digital, photographic pictures.
File formats: .jpeg, .jpg and more.

K

Ku-band
Used to refer to a range of frequencies that are available for use by satellite communication systems at around 30 GHz for the uplink and 20 GHz for the downlink.

L

LNB/LNC
Low Noise Block Converter.Receiving unit in the dish focus.Converts the satellite frequency range to the intermediate frequency of the receiver. 
 
LOF
Local Oscillator Frequency. Indicated in MHz or GHz, depending on LNB and frequency range received.Received frequency of receiver = transmitter frequency of satellite – LOF.
 
Low band
The lower part of the Ku-band downlink frequency range, from 10.7-11.7 GHz.

M

MATV
Master Antenna Television. More households receiving signals from a master antenna. 
 
MCPC
Multiple Channel Per Carrier.Refers to the multiplexing of a number of digital channels (video programs, audio programs and data services) into a common digital bit stream, which is then used to modulate a single carrier that conveys all of the services to the end user.
The single carrier supports multiple communication channels, hence the phase “multiple channel per carrier”.
The term MCPC is frequently used in the context of DVB systems, where the composite digital signal is referred to a a Transport Stream.
 
MFA
Masthead F-connector Amplifier. Triax amplifiers with F-connector for mast mounting.
 
MFC
Masthead F-connector Combiner. Triax combiners with F-connector for mast mounting.
 
Modulation with 22 KHz
For switching between 13/18 Volt and between 2 LNBs. When using universal LNB. For switching from lower to higher range (11.70-12.75 GHz).
 
Modulator
Output terminal on the satellite receiver or video tape recorder, for connection to the TV by means of an aerial cable. 
 
Multicrypt
DVB conditional access option based on a detachable Conditional Access (CA) module, which is supplied by the service provider to each subscriber.
The CA module is connected to the subscriber’s IRD via a standardized interface (the DVB Common Interface).
Multicrypt has the advantage that the same IRD can be used to receive services from providers using different and incompatible conditional access systems. 
 
Multifeed
Outdoor unit consisting of a dish and several LNBs for reception of various satellites.

N

Noise
Any undesired electrical disturbance in a circuit or communication channel.When combined with a received signal, it affects the receiver’s ability to correctly reproduce the original signal.
Also known as thermal noise. 
 
Noise figure
A method for quantifying the electrical noise generated by a practical device.
The noise figure is the ratio of the noise power at the output of a device to the noise power at the input to the device, where the input noise temperature is equal to the device, where the input noise temperature is equal to the reference temperature (290 K).
The noise figure is usually expressed in decibels

O

OTA
Over The Air.
 
Outdoor Unit
A designation for the equipment mounted outside, i.e. consisting of satellite dish/offset dish and one or more LNBs for reception of signals from one or more satellites, and DiSeqC converters, if any

P

Pay-Per-View (PPV)
The purchasing of programs and services by a television viewer or service user on an individual bases (e.g. televised coverage of a sports event).Access to purchased material is controlled by means of a Conditional Access System. See CAS.
 
Polarization
The phenomenon in which radio waves are restricted to certain directions of electrical and magnetic field variations, where these directions are perpendicular to the direction of wave travel.
By convention, the polarization of a radio wave is defined by the direction of the electric field vector.
Four senses of polarization are used in satellite transmissions: horizontal (X) linear polarization, vertical (Y) linear polarization, right-hand circular polarization and left-hand circular polarization.
 
Polarization Switching
The process of selecting one of two orthogonal polarizations (e.g. linear horizontal or linear vertical) for reception of satellite signals.
Polarization switching is implemented in the LNB or, more rarely, in a separate device inserted between the feedhorn and the LNA/LNB or integrated with the feedhorn.
 
Power Supply
A unit supplying power to electrical devices. Some electrical devices i.e. LNBs are powered through the coaxial cable to which the receiver supplies a voltage of 14 or 18 Volt.
 
Polarization Opposite
For better utilization of the available frequency bands the satellites transmit adjacent programs, with opposite polarization (horizontal and vertical or circular left or circular right).
Reception of both types of polarization requires two single LNBs or a V/H-LNB (Universal LNB).

Q

QPSK
Quatro Phase Shift Keying. A digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave).

R

Receiver
See satellite receiver

S

Satellite
A designation for the transmitting unit in space. Most often referred to by name and position, e.g. ASTRA 19º East, EUTELSAT 13º East.
 
Satellite Dish
A dish-shaped antenna (reflector) made of metal or metallic synthetic material for bunching of electromagnetic waves from the satellite into a focus.
 
Satellite receiver
The signals received and converted by the LNB cannot be processed by the TV. The satellite receiver processes them, and transmits audio and video signals (AV) to the TV through the outputs.
 
SCA
Single Channel Amplifier.
 
SCART
A connector on TV sets, VCRs, satellite receivers and other entertainment equipment for transmission of audio (sound) and video (picture) signals (AV).
 
SCF
Single Channel Filter.
 
SCPC
Single Channel Per Carrier.In SCPC systems, each communication signal is individually modulated onto its own carrier which is used to convey that signal to the end user.
A number of similar carriers share a common satellite transponder and use a unique portion of its bandwidth.
Each carrier supports a single communication channel only (e.g. one-half of a voice circuit), hence the phrase “single channel per carrier”.
 
Simulcast
Simultaneous transmission of an identical program or service using two or more standards or transmission media.Used to refer to a technique pioneered by EUTELSAT for transmitting one broadcast analogue FM television carrier and one digital television carrier in a single satellite transponder that would normally only support the FM TV carrier.
 
Simulcrypt
DVB conditional access option based on a commercial agreement between service providers, which allows access to a common population of proprietary IRDs. 
The IRD hardware is usually specific to the conditional access system and cannot be used to receive services delivered by service providers that are not party to the agreement.
 
Smart Card Reader
A device that allows insertion of a Pay-TV subscription smart card to allow access to the encrypted services on a Pay-TV operator.
Also requires the corresponding CAS to be available.
 
SMATV
Satellite Master Antenna Television.Collective television reception and distribution system serving a local population of users collocated in a block of flats, a hotel or other group-housing complex. 
SMATV systems use one or more high quality, centrally located antennas to receive the satellite signals, plus UHF and/or VHF antennas to receive local terrestrial broadcast services.
The satellite and terrestrial signals are distributed to the end-users via a dedicated cable distribution network.
Several different cable distribution architectures are possible.
 
S/N
Signal-to-Noise ratio.
A measure of the quality of an electrical signal, usually at the receiver output.
It is the ratio of the signal level to the noise level, measured within a specified bandwidth (typically the bandwidth of the signal).
It is usually expressed in decibels.
The higher the ratio, the better quality of the signal.

T

TA
Triax Amplifier.
 
TC
Triax Combiner.
 
TCC
Triax Compact Cabinet.
 
TCH
Triax Compact Headend.
 
TD
Triax Digital. 
 
TMA
Triax Masthead Amplifier.
 
TMC
Triax Masthead Combiner.
 
TMS
Triax Multi Switch. 
 
Transponder
Carries out the processing of one or more programs from a satellite, i.e. reception of data from earth station, amplification and radiation/transmission back to earth. 
A transmitter-receiver device that transmits signals automatically when it receives pre-determined signals.The term “satellite transponder” refers to a transmitter-receiver subsystem on-board the satellite that uses a single high power amplification chain and processes a particular range of frequencies (the “transponder bandwidth”). 
There are many transponders on a typical satellite, each capable of supporting one or more communication channels.
 
TS
Triax Splitter.

U

Universal LNB
A designation for a three-band LNB.
For reception of the ranges FFS (10.70 – 11.70 GHz), BBS (11.70 – 12.50) and FFS High Band (12.50 – 12.75 GHz).
The total range is divided into two bands; 
Low band:  10.70 – 11.80 GHz; LOF 9750 MHz
High band: 11.70 – 12.75 GHz; LOF 10600 MHz

V

Vertical polarization
Type of linear polarization where the electric field is approximately aligned with the local vertical plane at an on-ground transmission or reception point.
See also frequency reuse.
Viaccess
Digital coding/encryption method.

W

Wireless
Transmission of data or signals through the air – without cables/wires

X

Y

Z