Atualizada em 03/04/2012
Video Broadcasting. um padrão europeu para transmissão e recepção de
informação digital que é largamente adotado no mundo.
Existem sub protocolos DVB-S , para transmissões
por satélite, DVB-T, para transmissões terrestres,
a nossa TV Digital, e DVB-C , para cabo.
A sigla DVB-RCS é formado pelas
iniciais das palavras Digital Video
Broadcasting - Return Channel via Satellite
or Return Channel over System.
Tradução : Transmissão de Vídeo Digital - Canal de Retorno via Satélite.
É o sistema utilizado no acesso Korisko.
Texto reproduzido da WikiPedia
The DVB Group was started in the early 1990s to develop standards for digital
TV for Europe. Every digital TV system in Europe - and in many other territories
- uses DVB.
For further information about the DVB Group, manufacturers, standards and
services please see their website
Here's a short intro to its use for high-speed internet via satellite.
DVB is a European Broadband Network - almost by accident!
Although DVB was developed by the TV industry for digital TV, some
far-sighted people realised that a high-speed data pipe for TV could just as
well be used as a high-speed data pipe for, well, data. Today, there's a
Broadband Network available to every home in Europe - as long as it can install
a small satellite dish. And it is available in the UK now from BeyonDSL.
DVB stands for Digital Video Broadcasting
DVB is the European standard for digital TV and, as such, provides a very
high-speed, robust transmission chain capable of the many Megabits per second
needed for each of several hundred MPEG-2 digital TV channels.
In the old days, a typical satellite transponder had about enough bandwidth
for a single analogue PAL colour TV channel. So if your satellite had 22
transponders, you could transmit 22 TV channels.
Using DVB digital technology and standards means the same transponder can
transmit around 40 Megabits per second. A typical PAL VHS standard TV channel
can be compressed by DVB MPEG-2 to around 4 Megabits per second. Channels can be
mixed - or “multiplexed” - in the same transponder giving a rule-of-thumb of
10 TV channels (each around 4Mb/s) in a typical (40Mb/s) transponder.
The core system is the same for digital satellite, cable and terrestrial TV
with different modulation methods for each mode. In the UK, for some reason,
Cable companies have chosen not to adopt the DVB standard.
DVB sets the Standards for the World
Many people are taken aback to find that Europe can lead the world in digital
technology. Especially those brainwashed to think that the internet and the
World Wide Web are purely an American invention. The DVB Group has made Europe's
TV technology more advanced than elsewhere. The co-operation has led to European
standards which have removed “format wars” so successfully that a
Scandinavian DVB TV receiver built for the Italian market can receive French TV
channels in the UK.
DVB for Satellite, Cable and Terrestrial TV
The basic "unit" of the DVB system is the DVB multiplex - a very
high speed data stream containing data packets from a number of individual
smaller data streams. The parameters can be chosen so that a DVB-S multiplex -
that transmitted from a single satellite transponder - is the same effective
bandwidth as a DVB-C multiplex - that transmitted down a single analogue cable
This allows any service contained within a DVB multiplex to pass down any
current TV infrastructure to be received on an appropriate DVB receiver -
whether satellite or cable.
DVB for Internet & Interaction
DVB has been developed to include encapsulation techniques which allow the
MPEG-2 data packets to carry TCP/IP traffic at the same multi-Megabits/sec speed
as digital television. This allows both digital TV and internet traffic to
co-exist on the same system and be received by either DVB PC cards or DVB
DVB is under development to include a number of capabilities of interest to
the interactive community: standard return path protocols via satellite and
cable, open platforms, MHEG and compatibility with HTTP, IPV6 and other internet
protocols. DVB today has the ability to carry TCP/IP - and hence any other
standard using TCP/IP - at a very high speed.
DVB is a new Mode for the Internet
Satellite has been considered a poor relation in the market which thinks it
invented the internet - the US. Perhaps they have never forgiven the UK for
Arthur C Clarke, Alan Turing, and Tim Berners-Lee!
Satellite is the cheapest and easiest way of breaking the geographical
barriers of the internet. Thanks to services like Opensky from BeyonDSL, anyone
can upgrade to broadband reception as long as they can install a small dish and
have a phone connection of some sort. No-one has to dig up the road to lay
More than that, open-minded internet organisations are starting to realise
the astounding possibilities of satellite for distribution of content and
multimedia experiences. There is no cheaper way of giving people access to the
latest Service Pack, Virus Update or Madonna Concert.
DVB and BeyonDSL
The people in BeyonDSL are very proud of being involved in bringing satellite
broadband internet to the UK since 1997. Whether project managing the very first
independent DVB multiplex carrying TV and Internet (in Y Tower D of the BT
Tower) or building and running the direct internet link from Telehouse to
satellite homes across Europe, we have been at the forefront of this technology.
Our team has developed world-leading technology and systems - all using DVB.
With a pedigree including Astra, Eutelsat, Merlin, SMS, Convergence1,
Convergence2, BT, Energis and the BBC, we can now bring you the best in one-way,
hybrid and two-way DVB satellite services.