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This article is about digital television standard. For Islamic Development Bank, see Islamic Development Bank.
Integrated Services Digital Broadcasting (ISDB) is a Japanese standard for digital television (DTV) and digital radio used by the country's radio and television stations. ISDB replaced the previously used MUSE "Hi-vision" analogue HDTV system. [edit] Countries and territories using ISDB-T[edit] Asia/Pacific
[edit] America
[edit] Introduction  ISDB is maintained by the Japanese organization ARIB. The standards can be obtained for free at the Japanese organization DiBEG website and at ARIB. The core standards of ISDB are ISDB-S (satellite television), ISDB-T(terrestrial), ISDB-C (cable) and 2.6GHz band mobile broadcasting which are all based on MPEG-2 video and audio coding as well as the transport stream described by the MPEG-2 standard, and are capable of high definition television (HDTV). ISDB-T and ISDB-Tsb are for mobile reception in TV bands. 1seg is the name of an ISDB-T service for reception on cell phones, laptop computers and vehicles. The concept was named for its similarity to ISDN, because both allow multiple channels of data to be transmitted together (a process called multiplexing). This is also much like another digital radio system, Eureka 147, which calls each group of stations on a transmitter an ensemble; this is very much like the multi-channel digital TV standard DVB-T. ISDB-T operates on unused TV channels, an approach taken by other countries for TV but never before for radio. [edit] Video and audio compressionISDB has adopted the MPEG-2 video and audio compression system. ATSC and DVB also adopted the same system. DVB and ISDB also provide for other video compression methods to be used, including JPEG and MPEG-4, although JPEG is only a required part of the MHEG standard. Brazil is using ISDB for terrestrial broadcasting (ISDB-T) with video encoded with MPEG-4 AVC (H.264) and audio with HE-AAC ([2]). Other countries in South America are following Brazil adopting ISDB-T with H.264 and HE-AAC. [edit] TransmissionThe various flavors of ISDB differ mainly in the modulations used, due to the requirements of different frequency bands. The 12 GHz band ISDB-S uses PSK modulation, 2.6 GHz band digital sound broadcasting uses CDM and ISDB-T (in VHF and/or UHF band) uses COFDM with PSK/QAM. [edit] InteractionBesides audio and video transmission, ISDB also defines data connections (Data broadcasting) with the internet as a return channel over several media (10Base-T/100Base-T, Telephone line modem, Mobile phone, Wireless LAN (IEEE 802.11) etc.) and with different protocols. This is used, for example, for interactive interfaces like data broadcasting (ARIB STD B-24) and electronic program guides (EPG). [edit] Interfaces and EncryptionThe ISDB specification describes a lot of (network) interfaces, but most importantly the Common Interface for Conditional Access (ARIB STD-B25) with the Common Scrambling Algorithm (CAS) system called MULTI2 required for (de-)scrambling television. The ISDB CAS system is operated by a company named B-CAS in Japan; the CAS card is called B-CAS card. The Japanese ISDB signal is always encrypted by the B-CAS system even if it is a free television program. That is why it is commonly called "Pay per view system without charge".[citation needed] An interface for mobile reception is under consideration.[citation needed] ISDB supports RMP (Rights management and protection). Since all digitial television (DTV) systems carry digital data content, a DVD or high-definition (HD) recorder could easily copy content losslessly. Hollywood[who?] requested copy protection; this was the main reason for RMP being mandated. The content has three modes: “copy once”, “copy free” and “copy never”. In “copy once” mode, a program can be stored on a hard disc recorder, but cannot be further copied; only moved to another copy-protected media—and this move operation will mark the content “copy one generation”, which is mandated to permanently prevent further copying. “Copy never” programming may only be timeshifted and cannot be permanently stored. Currently[when?], the Japanese government is evaluating using the Digital Transmission Content Protection (DTCP) "Encryption plus Non-Assertion" mechanism, to allow making multiple copies of digital content between compliant devices[3]. [edit] ReceiverThere are two types of ISDB receiver: TV and STB (Set top box). The aspect ratio of ISDB television is 16:9; televisions fulfilling these specs are called Hi-vision TVs. There are three TV types: CRT (Cathode ray tube), PDP (Plasma display panel) and LCD (Liquid crystal display), with LCD being the most popular Hi-Vision format on the Japanese market right now. LCD share as measured by JEITA in November 2004 was about 60%. While PDP set occupies the high end market with units that are over 50 inches (1270 mm), PDP and CRT set shares are about 20% each. CRT set are considered low end for Hi-Vision. STB is sometimes referred to as digital tuner. High-end ISDB STB have several interfaces:
[edit] Copy Protection TechnologyEvery TV broadcast (including free TV) is encrypted with "Copy-Once", which allows users to record to a digital media (D-VHS, DVD, HDD, etc) but does not allow dubbing to another digital media. On the other hand, the "Copy-Once" technology does not prohibit all types of dubbing. It is possible to dub to an analog media (such as standard VHS) and if recorded to an HDD, it will allow users to "Move" the contents to a D-VHS, but not copy. In contrast, 1seg digital broadcasts which are for low-bandwidth mobile reception and occupy 1/13th of a digital channel, are transmitted 'in the clear' and do not carry copy protection information. Many users are also very worried about the recent news of severe protection in the future. There are modes in ISDB to not allow the output of signal from an Analog connector (D-connector, Component, Composite, S-Video, etc). There are already plans to not allow analog output for "Copyright Protection" reasons. (Same as Blu-ray and HD DVD) This will make all currently sold STB Tuners, and the majority of LCD/Plasma TVs without HDMI inputs unusable. Plus all analog VHS, D-VHS that can only record via analog input, and all DVD players will also become unusable. These more limiting copy protection technologies will all start after analog broadcasting ends (when there won't be any choice for viewers). Currently, no financial assistance schemes have been announced, and viewers without proper devices will be forced to buy a new compatible TV or set top box in order to view ISDB broadcasts. Though not clear, it is said that there are also plans to protect all programs with "Copy-Never". The copy protection on ISDB broadcasts can be circumvented with the proper hardware and software.[4] Brazilian standard ISDB-Tb does not implement this copy protection mechanism. [edit] B-CAS CardThe B-CAS card is required to decode all broadcasts. These cards are included with every digital TV or Tuner at no charge. To use this card, you must agree to the statement written on the registration card. Despite the fact that the card must be inserted to watch TV, if you don't agree to the statement, then the user cannot watch digital broadcasts. Essentially, users are "forced" to agree with the statement. Though registration is not required, it is recommended to fully enjoy interactive programs. Unregistered B-CAS card displays a watermark in a corner of the screen, suggesting the user to register. However, many viewers worry about the leaking of personal information, and the power/rights the TV stations have to access personal information for almost every citizen in Japan. In case of loss or destruction, new B-CAS card of the same number can be issued for a fee of 2,000 yen.[5] [edit] Services
[edit] ISDB-S[edit] HistoryJapan started digital broadcasting using the DVB-S standard by PerfecTV in October/1996, and DirecTV in December/1997, with communication satellites. Still, DVB-S did not satisfy the requirements of Japanese broadcasters, such as NHK, key commercial broadcasting stations like Nippon Television, TBS, Fuji Television, tv asahi, TV Tokyo, and WOWOW (Movie-only Pay-TV broadcasting). Consequently, ARIB developed the ISDB-S standards. The requirements were HDTV capability, interactive services, network access and effective frequency utilization, and other technical requirements. The DVB-S standard allows the transmission of a bit stream of roughly 34 Mbit/s with a satellite transponder, which means the transponder can send one HDTV channel. Unfortunately, the NHK broadcasting satellite had only four vacant transponders, which led ARIB and NHK to develop ISDB-S: The new standard could transmit at 51 Mbit/s with a single transponder, which means that ISDB-S is 1.5 times more efficient than DVB-S and that one transponder can transmit two HDTV channels, along with other independent audio and data. Digital satellite broadcasting (BS digital) was started by NHK and followed commercial broadcasting stations on 1 December 2000. Today, SKY PerfecTV!, successor of Skyport TV, and Sky D, CS burn, Platone, EP, DirecTV, J Sky B, and PerfecTV!, adopted the ISDB-S system for use on the 110 degree (east longitude) wide-band communication satellite. [edit] Technical specificationSummary of ISDB-S (Satellite digital broadcasting)
[edit] ChannelFrequency and channel specification of Japanese Satellites using ISDB-S
[edit] ISDB-T[edit] HistoryHDTV was invented at NHK STRL (Japan Broadcasting Corporation's Science & Technical Research Laboratories). The research for HDTV started as early the 1960s, though a standard was proposed to the ITU-R (CCIR) only in 1973. By the 1980s, a high definition television camera, cathode-ray tube, video tape recorder and editing equipment, among others, had been developed. In 1982 NHK developed MUSE (Multiple sub-nyquist sampling Encoding), the first HDTV video compression and transmission system. MUSE used digital video compression, but for transmission frequency modulation was used after a digital-to-analog converter converted the digital signal. In 1987, NHK demonstrated MUSE in Washington D.C. and NAB. The demonstration made a great impression in the U.S. As a result, the U.S. developed its own ATSC terrestrial DTV system. Europe also developed their own DTV system, DVB. Japan began R&D of a completely digital system in the 1980s that led to ISDB. Japan began terrestrial digital broadcasting, using ISDB-T standard by NHK and commercial broadcasting stations, on 1 December, 2003. [edit] Feature ISDB-T is characterized by the following features:
[edit] AdoptionISDB-T was adopted for commercial transmissions in Japan in December 2003. It currently comprises a market of about 100 million television sets. ISDB-T had 10 million subscribers by the end of April 2005. Along with the wide use of ISDB-T, the price of STB is getting low. The price of ISDB-T STB in the lower end of the market is ¥19800 as of 19 April 2006.[6] By November 2007 only a few older, low-end STB models could be found in the Japanese market (average price U$180), showing a tendency towards replacement by high-end equipment like PVRs and TV sets with inbuilt tuners. The Dibeg web page confirms this tendency by showing low significance of the digital tuner STB market in Japan.[7] Brazil, which currently uses an analogue TV system (PAL-M) that slightly differs from any other countries, has chosen ISDB-T as a base for its DTV format, calling it ISDB-Tb or internally SBTVD (Sistema Brasileiro de Televisão Digital-Terrestre). The Japanese DiBEG group incorporated the advancements made by Brazil -MPEG4 video codec instead of ISDB-T's MPEG2 and a powerful interaction middleware called Ginga- and has renamed the standard to "ISDB-T International".[8] Other than Argentina, Brazil, Peru and Chile[9] which have already selected ISDB-Tb, there are other Latin American countries, mainly from Mercosur, such as Venezuela[10], that are considering ISDB-Tb, which could provide economies of scale and common market benefits from the regional South American manufacturing instead of importing ready-made STBs as is the case with the other standards. Also, it has been confirmed with extensive tests realized by Brazilian Association of Radio and Television Broadcasters (ABERT), Brazilian Television Engineering Society (SET) and Mackenzie Presbiterian University the insufficient quality for indoor reception presented by ATSC and, between DVB-T and ISDB-T, the last one presented superior performance in indoor reception and flexibility to access digital services and TV programs through non-mobile, mobile or portable receivers with impressive quality.[11] Nevertheless, in August 2007 Uruguay officially chose DVB-T + DVB-H as its DTV standard.[12] The ABERT–SET group in Brazil did system comparison tests of DTV under the supervision of the CPqD foundation. The comparison tests were done under the direction of a work group of SET and ABERT. The ABERT/SET group selected ISDB-T as the best choice in digital broadcasting modulation systems among ATSC, DVB-T and ISDB-T. ISDB-T was singled out as the most flexible of all for meeting the needs of mobility and portability. It is most efficient for mobile and portable reception. On June 29, 2006, Brazil announced ISDB-T-based SBTVD as the chosen standard for digital TV transmissions, to be fully implemented by 2016. By November 2007 (one month prior DTTV launch), a few suppliers started to announce zapper STBs of the new Nippon-Brazilian SBTVD-T standard, at that time without interactivity. The implementation rollout in Brazil is proceeding successfully although some voice like Philips' say [1] that its implementation could be faster. It terms of broadcasting, the implementation plan seems to be on target. In only eight months since the start, the digital signal is present in four state capitals and by the end of 2008 another three capitals will receive the signal. In terms of end-customers the implementation could be better, since at the moment it is estimated[by whom?] only 20,000 set-top boxes have been sold. Part of this low sales number can be explained by the prices that in the beginning ranged from BRL 600 to BRL 1,100. However, recently new set-top boxes were launched in market at R$300 (approx US$ 150) that will probably increase set-top box sales. Another reason to explain low sales level is the interactivity service not available yet. That is because the "middleware" developed by Brazilian universities (PUC Rio and Federal University of Paraiba) will be finished only in October 2008.[dated info] Once finished it is expected[by whom?] the interactivity will be a strong appeal bringing more and more people to digital TV world. Additionally, mobile TV started successfully with the launch of Samsung and Toshiba cell phones with ISDB-T "one-seg" tuners. Its main appeal is that the service is free. That is a very impressive accomplishment in a short period since Brazil launched its digital mobile TV for free. In other countries such accomplishment occurred years later, and in others like the U.S. and Europe this is far from reality and probably won't be for free[citation needed].[13] Subscription mobile TV in Germany using DBV-H has been dubbed "a failure".[13] In Italy the cost of receiving mobile TV over DVB-H costs the user €9.90 per month just for the basic channel package.[14] On April 23, 2009 Peru announced its decision to adopt ISDB-T as the digital terrestrial television standard. This decision was taken on the basis of the recommendations by the Multi-sectional Commission to assess the most appropriate standard for the country. On August 28, 2009, Argentina officially adopted the ISDB-T system[15] calling it internally SATVD-T (Sistema Argentino de Televisión Digital - Terrestre).[16] The idea is to implement ISDB-T to the whole Mercosur players (exception of Uruguay) with obvious gains in scale. Other countries testing or studying ISDB-T standard: Venezuela, Ecuador in South America and the Philippines in Asia. On September 14, 2009, Chile announced it was adopting the ISDB-T standard because it adapts better to the geographical makeup of the country, while allowing signal reception in cell phones, high-definition content delivery and a wider variety of channels.[9] On October 6, 2009, Venezuela officially adopted the ISDB-T standard.[17] [edit] Technical specificationSegment structure ARIB has developed a segment structure called BST-OFDM (see figure). ISDB-T divides the frequency band of one channel into thirteen segments. The broadcaster can select which combination of segments to use; this choice of segment structure allows for service flexibility. For example, ISDB-T can transmit both LDTV and HDTV using one TV channel or change to 3 SDTV, a switch that can be performed at any time. ISDB-T can also change the modulation scheme at the same time.
FIGURE: Spectrum of 13 segments structure of ISDB-T [edit] Summary of ISDB-T
[edit] ChannelSpecification of Japanese terrestrial digital broadcasting using ISDB-T
[edit] 2.6 GHz Mobile satellite digital audio/video broadcastingMobaHo! is the name of the services that uses the Mobile satellite digital audio broadcasting specifications. MobaHo! started its service on 20 October, 2004. Ended in 31 March 2009 [edit] ISDB-TsbISDB-Tsb is the terrestrial digital sound broadcasting specification. The technical specification is the same as ISDB-T. ISDB-Tsb supports the coded transmission of OFDM siginals. [edit] ISDB-CISDB-C is cable digital broadcasting specification. The technical specification is developed by JCTEA. [edit] ISDB-TmmISDB-Tmm (Terrestrial mobile multi-media) will use suitable number of segments by station with video coding MPEG-4 AVC /H.264. With multiple channel, ISDB-Tmm will serve for dedicating contents such as sport, movie, music channel and other with CD quality sound. This service will use VHF band, 170-222 MHz after analog television close down in July 2011. [edit] StandardsARIB and JCTEA developed the following standards. Some part of standards are located on the pages of ITU-R and ITU-T.
[edit] Table of terrestrial HDTV transmission systems
[edit] See alsoGeneral category
Transmission technology
[edit] References
[edit] External links
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