Developing DVB as the standard for the global digital television broadcasting through the satellite and the establishment of terestrial begin DVB Project in 1993. DVB Project has approximately 250 institutions that came from an 30-state and consists of a broadcaster, manufacturers, network operators, regulatory bodies and academic institutions. DVB Project does not perform the function as a regulator but based on the work of business and commercial aspects.
In further development of the DVB Project has successfully developed a series of specifications that DVB is not limited to video broadcasting, but has also penetrated to the applications and multimedia services.
Why DVB?DVB was developed based on the background the importance of the broadcasting system is o open system is supported by the ability of interoperability, flexibility and commercial aspects. As an open system, the DVB standard can be used by the vendor to develop a variety of services and innovative value-added services that mutually compatible with devices from vendors other DVB. In addition, the digital program that is sent based on DVB specifications can be transferred from one transmission medium to another transmission medium with a cheap and easy. Approach taken by DVB is to maximize Existing devices and systems available in the general commercial market.
With digital technology, DVB can utilize the bandwidth usage more efficient. A satellite transponder that normally can only be used for one analog TV programs, using the DVB can be used to broadcast digital TV channel 8. In addition to adding capacity channel TV, the media transmission terestrial image quality can be better in the media and even cable TV, DVB-C services offer two-way interaction.
DVB services inf the future will consist of various types of program that was developed through a number of transmission channels. So that the IRD can be tune for certain services automatically through the navigation system is user friendly tool to add DVB navigation's tool such us DVB-SI (Service Information) is an extension of the Program Specific Information (PSI) from the MPEG-2. DVB Service information on the work as the header of the MPEG container so that the receiver can find out what is needed to decode signal.
Transmision
DVB standard can be applied to a variety of media ranging from satellite transmission (DVB-S), cable (DVB-C) or radio waves terestrial (
DVB-T).
Standard DVB-S products is the first project, which allow you to DVB DVB signals via satellite. Document describes the various tools for channel code modulation, including the implementation of the Binary Phase Shift Keying (BPSK).
System modulation and channel coding system in the DVB Cable (CATV) is described in the document DVB-C standard. This document is a basis for further development of specifications [DVB-use of CS, (Satellite) Master Antenna TV (SMATV).
DVB also manage media use in the terrestrial transmission of DVB-T specification. Utilization of micro-wave signals for delivery over DVB MMDS (Multichannel Microwave Distribution System) can be divided into two specifications: for the MMDS frequencies above 10 GHz (DVB-MS) using DVB-S specification for the frequency below 10 GHz (DVB-MC) is based mainly on the DVB-C.
Conditional Access System
CAS (Conditional Access System) is a subsystem that serves as access control to the program or service so that you can receive service only user who has obtained authorization. CAS consists of several blocks of which technique to make the program or service, Subscriber Management System (SMS), Subscriber Authorization System (SAS) etc.. SMS is essentially a data base containing information of a customer service, while the SAS functions to encrypt and send the code-words that allows an IRD can running program. DVB Project is not to make CAS as part of the DVB standard. However, developing a DVB Common Scrambling algorithm, the tools to make Transport Program Elementary streams or streams. DVB free use of the appropriate type of CAS with the service needs of some members DVB vendors that offer products in a competitive commercial.
Many of the services offered in the DVB will require some form of interaction between the user and the program provider or network operator. Interaction can become command transmission but may also require the interaction is quite intensive, as happened in the communication through the Internet. Interactive TV is identified as one of the important keys that will be the digital transmission system in the future. Various members of DVB has developed a comprehensive plan of introducing interactive TV since 1997. The occurrence of convergence in this area allows the back of a point in the future world broadcasting.
Various return channel DVB specifications have been published by ETSI including DVB-rcc (Cable) and DVB-RCT (Telephone or ISDN), which is the complement of the DVB-NIP (Network Independent Protocols) is based on MPEG-2 DSM-CC (Digital Storage Media-Command and Control)
Development of DVB
DVB classified for the new technology vendors, network providers and the broadcaster. One of the strengths of the DVB technology lies in the fact that DVB transmission allows some sizzle on the high-speed data are point-to-multipoint with a safe from possible transmission errors. To enable transmission of data, including the possibility of repeating the same data transmission at a fixed time interval or not they still have developed a DVB specification for data broadcasting.
Although the DVB project has reached the stage various development activities continue to be among, the development of solutions to broadcast DVB High Definition Television (HDTV), Specification for Digital Satellite News Gathering (SNG-D), Specification for the interface that will connect the world with DVB signal network PDH, SDH and ATM, which is managed by the operator's telecommunication network, etc.
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