DVB

Dig­i­tal Video Broad­cast­ing (DVB) is a suite of inter­na­tion­al­ly accept­ed open stan­dards for dig­i­tal tele­vi­sion. DVB stan­dards are main­tained by the DVB Project, an inter­na­tion­al indus­try con­sor­tium with more than 270 mem­bers, and they are pub­lished by a Joint Tech­ni­cal Com­mit­tee (JTC) of Euro­pean Telecom­mu­ni­ca­tions Stan­dards Insti­tute (ETSI), Euro­pean Com­mit­tee for Elec­trotech­ni­cal Stan­dard­iza­tion (CENELEC) and Euro­pean Broad­cast­ing Union (EBU). The inter­ac­tion of the DVB sub-stan­dards is described in the DVB Cook­book. Many aspects of DVB are patent­ed, includ­ing ele­ments of the MPEG video cod­ing and audio cod­ing

 DVB‑S

DVB‑S is an abbre­vi­a­tion for Dig­i­tal Video Broad­cast­ing — Satel­lite; it is the orig­i­nal Dig­i­tal Video Broad­cast­ing For­ward error cor­rec­tion and demod­u­la­tion stan­dard for Satel­lite Tele­vi­sion and dates from 1994, in its first release, while devel­op­ment last­ed from 1993 to 1997. The first appli­ca­tion was com­mer­cial­ly avail­able in France via Canal+, enabling dig­i­tal­ly broad­cast, satel­lite-deliv­ered Tele­vi­sion to the pub­lic. It is used via satel­lites serv­ing every con­ti­nent of the world. DVB‑S is used in both Mul­ti­ple Chan­nel Per Car­ri­er (MCPC) and Sin­gle chan­nel per car­ri­er modes for Broad­cast Net­work feeds as well as for Direct Broad­cast Satel­lite ser­vices like Sky (UK & Ire­land) via Astra in Europe, Dish Net­work and Globe­cast in the U.S. and Bell TV in Cana­da. While the actu­al DVB‑S stan­dard only spec­i­fies phys­i­cal link char­ac­ter­is­tics and fram­ing, the over­laid trans­port stream deliv­ered by DVB‑S is man­dat­ed as MPEG‑2, known as MPEG trans­port stream (MPEG-TS).  Some ama­teur tele­vi­sion repeaters also use this mode in the 1.2 GHz ama­teur band.

 DVB‑T

Dig­i­tal ter­res­tri­al tele­vi­sion (DTTV or DTT) is the tech­no­log­i­cal evo­lu­tion of broad­cast tele­vi­sion and an advance­ment of ana­log tele­vi­sion. DTTV broad­casts land-based (ter­res­tri­al) sig­nals. The pur­pos­es of dig­i­tal ter­res­tri­al tele­vi­sion, sim­i­lar to dig­i­tal ver­sus ana­log in oth­er plat­forms such as cable, satel­lite, and telecom­mu­ni­ca­tions, reduced use of spec­trum and to pro­vide more capac­i­ty than ana­log, pro­vide bet­ter qual­i­ty pic­ture, and to low­er oper­at­ing costs for broad­cast and trans­mis­sion (after the ini­tial upgrade costs). A ter­res­tri­al imple­men­ta­tion of dig­i­tal tele­vi­sion (DTV) tech­nol­o­gy uses an aer­i­al to broad­cast to a con­ven­tion­al tele­vi­sion anten­na (or aer­i­al) instead of a satel­lite dish or cable tele­vi­sion con­nec­tions.

Com­pet­ing vari­ants of broad­cast tele­vi­sion sys­tems are being used around the world. Advanced Tele­vi­sion Stan­dards Com­mit­tee cre­at­ed the ATSC stan­dards that use an ATSC tuner in North Amer­i­ca and South Korea—an evo­lu­tion from the ana­log Nation­al Tele­vi­sion Stan­dards Com­mit­tee (NTSC) stan­dard. Inte­grat­ed Ser­vices Dig­i­tal Broad­cast­ing (ISDB‑T) is used in Japan, with a vari­a­tion of it being used in most of South Amer­i­ca. DVB‑T is the most preva­lent, cov­er­ing Europe, Aus­tralia, New Zealand, Colom­bia and some coun­tries of Africa. DMB‑T/H is Chi­na’s own stan­dard (includ­ing Hong Kong, though Hong Kong’s cable oper­a­tors use DVB); the rest of the world remains most­ly unde­cid­ed, many eval­u­at­ing mul­ti­ple stan­dards. ISDB‑T is very sim­i­lar to DVB‑T and can share front-end receiv­er and demod­u­la­tor com­po­nents. Sev­er­al Euro­pean coun­tries have switched from ana­log to dig­i­tal ter­res­tri­al tele­vi­sion, with the rest hop­ing to have com­plet­ed the switchover most­ly by 2012.


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