Useful Information

Glosary

Amerhis:

On-board multimedia communications processing system included in the Amazonas 1 and Amazonas 2 satellite that provides direct interconnection between users, multiplexing the signal on board the satellite, which reduces the cost of terrestrial equipment and optimises frequency bands, making a better use of power resources on board the satellite.

BSS Band (Broadcast Satellite Service):

Frequency band for broadcasting services via satellite.

C Band:

Satellite range that uses 3.625 to 4.2 GHz frequencies for downlink.For uplink, from 5.950 to 6.425 GHz.

FSS Band (Fixed Satellite System):

Frequency band addressed to the fix service via satellite.

Ka Band:

The range of frequencies in which the Ka band operates is between 17.3 GHz and 31 GHz. It has a wide scope of locations and their wavelengths carrying large amounts of data.

Ku Band:

This range, used by television and radio companies, extends from 10.70 to 12.75 GHz for reception and from 12.75 to 14.50 for uplink. This is the most extensive band in Europe; it only requires small satellite dishes to receive the signal.

X Band:

This band is exclusively reserved for military use.

Channel:

Part of the base band on which a specific signal is transmitted. The bandwidth of a television channel is, for example, 6 Mhz in the United States and 8 MHz in Europe for cable and the analogic reception. In HISPASAT satellites, this may reach from 33 to 500 MHz.

CATV (Cable Television):

Communal Antenna Television. Expression used to refer to the communal reception of satellite signals or communal television distribution.

DBS (Direct Broadcasting Satellite):

Initially, this referred to Ku band satellites that used high power tubes such as TDF, TV Sat and Tele X.

Landing Right:

License that is conferred to the satellite operators so that operators can use a satellite space capacity within its coverage area.

Decoder:

Equipment that, together with an intelligent card, allows users to access the service. In the case of the reception of digital signals, the decoder is integrated in the receiver (IRD).

Digital:

A system where information is processed by means of "on-off" (connection-disconnection), "high-low" or "1-0" electric impulses instead of continuous variation signals as is the case with analogical systems.

DTH (Direct To Home):

This refers to the transmission of radio signals from a satellite directly to the user's home. The signal is received by means of a small satellite dish. The most popular DTH service is satellite TV.

DVB (Digital Video Broadcasting):

This is a European standard for digital television broadcasting linked to the MPEG-2 compression format.

Frequency:

Number of oscillations per time unit. Frequency monitors the number of times this phenomenon takes place within a given interval. Satellite signals are transmitted in Gigahertz (GHz), i.e., with electromagnetic waves that oscilate a billion times per second.

Gigahertz (GHz):

Unit of habitual measurement for the frequencies of emission of the satellites. It is equivalent to billion cycles per second, Herzio (Hz).

G/T:

Relation between the profit and the noise temperature of a receiving systemt.It's value is an influential factor in the quality of reception.

ISP (Internet Service Provider):

Organisation that, apart from providing access to Internet for individuals or legal entities, offers a series of data between any pair of computers connected to subsidiary networks.

LMDS (Local Multipoint Distribution System):

LMDS is radio technology that has been developed to provide local wireless broadband access. It provides access to voice, data, Internet and video services. It uses a 25 GHz (or higher) radio band.

MMDS (Microwave Multipoint Distribution System):

This refers to wireless cable. A terrestrial broadcasting system that uses the band between 2.5 and 2.7 GHz. MMDS may be analogical (Pal, Secam, NTSC) or digital. It is quite common in some countries, especially in Africa.

Multiplex:

This is the type of signal that re-groups a group of compressed programmes broadcast simultaneously on the same frequency.

Platform:

Also called Service Module. It is responsible for keeping the satellites operational in their orbital position throughout their life-cycle.

Broadband Platform:

A Broadband Platform is a system which integrates a terrestrial infrastructure or HUB, the satellite and the VSAT (Very Small Aperture Terminal) terminals, to offer IP services as well as Internet access, video conferencing, VoIP…, within the coverage offered area by the satellite.

EIRP:

Power equivalent to that radiated by an antenna that emits in all directions. It originates from the power of the transmitter and from the antenna's power gain. The EIRP is expressed in dBW (decibel/Watts). It's value is an inportant factor in the quality of the reception.

QPSK (Quaternary Phase Shift Keying):

This is a modulation method used for satellite digital transmissions. The information is in the modulation signal phase, in four states.

Broadband Network:

High speed transmission network in which two or more signals can share the same transmission medium. According to recommendation I.113 of the ITU-T, the standardization body of the International Telecommunications Union, broadband consists of the techniques capable of transmitting more quickly than a primary ISDN access, be it at 1.5 or 2 Mbps.

ISDN (Integrated Services Digital Network):

It combines digital services of voice and information across the net in a single cable. It makes it possible to offer both services on one cable. The basic channel is 64 Kbit/s.

SNG (Satellite News Gathering):

Transportable stations to gain access to satellites.

TCP / IP (Transmission Control Protocol / Internet Protocol):

Group of protocols, the basis of the Internet. The first divides information into packets at the source and later restores it at the destination, while the second correctly routes the information through the network.

TDMA:

The technologies which enable a transponder can be shared between several stations. In the TDMA the entire available bandwidth is assigned to every user, but only during a limited period of time that repeats periodically.

DTT:

Digital Terrestrial Television.

Transponder:

Also called a repeater. This is the name given to the re-transmitter on board satellites, responsible for re-transmitting signals received from a station to another place on Earth. It is associated to one or more transmission antennas that establish the area covered by the beam transmitted, based on their shape and positioning.

UHF:

Abbreviation for Ultra High Frequencies, that refers to the frequency band between 300 and 3000 MHz. They correspond to European television channels 21 to 69.

VHF:

Abbreviation for Very High Frequencies, that refers to the frequency band between 30 and 300 MHz In Europe, these correspond to bands I and III, for television, and II for FM.

VSAT (Very Small Aperture Terminal):

Terminal with an small size antenna (from 0.65 to 1.2 m).

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