High-Definition Television (or HDTV) is a digital television broadcasting system with higher resolution than traditional television systems (standard-definition TV, or SDTV). HDTV is digitally broadcast; the earliest implementations used analog broadcasting, but today digital television (DTV) signals are used, requiring less bandwidth due to digital video compression.
Demise of analog HD systems
However, even that limited standardization of High-definition television did not lead to its adoption, principally for technical and economic reasons. Early HDTV commercial experiments such as NHK's MUSE required over four times the bandwidth of a standard-definition broadcast, and despite efforts made to shrink the required bandwidth down to about two times that of SDTV, it was still only distributable by satellite with one channel shared on a daily basis between seven broadcasters. In addition, recording and reproducing an HDTV signal was a significant technical challenge in the early years of HDTV. Japan remained the only country with successful public broadcast analog HDTV. Digital HDTV broadcasting started in 2000 in Japan, and the analog service ended in the early hours of 1 October 2007.
However, even that limited standardization of High-definition television did not lead to its adoption, principally for technical and economic reasons. Early HDTV commercial experiments such as NHK's MUSE required over four times the bandwidth of a standard-definition broadcast, and despite efforts made to shrink the required bandwidth down to about two times that of SDTV, it was still only distributable by satellite with one channel shared on a daily basis between seven broadcasters. In addition, recording and reproducing an HDTV signal was a significant technical challenge in the early years of HDTV. Japan remained the only country with successful public broadcast analog HDTV. Digital HDTV broadcasting started in 2000 in Japan, and the analog service ended in the early hours of 1 October 2007.
HDTV sources
High-definition television the rise in popularity of large screens and projectors has made the limitations of conventional Standard Definition TV (SDTV) increasingly evident. An HDTV compatible television set will not improve the quality of SDTV channels. To display a superior picture, high definition televisions require a High Definition (HD) signal. Typical sources of HD signals are as follows:
Over the air with an antenna. Most cities in the US with major network affiliates broadcast over the air in HD. To receive this signal an HD tuner is required. Most newer high definition televisions have an HD tuner built in. For HDTV televisions without a built in HD tuner, a separate set-top HD tuner box can be rented from a cable or satellite company or purchased.
Cable television companies often offer HDTV broadcasts as part of their digital broadcast service. This is usually done with a set-top box or CableCARD issued by the cable company. Alternatively one can usually get the network HDTV channels for free with basic cable by using a QAM tuner built into their HDTV or set-top box. Some cable carriers also offer HDTV on-demand playback of movies and commonly viewed shows.
Satellite-based TV companies, such as DirecTV and Dish Network (both in North America), Premiere (in Germany), TeleDunya (in Turkey), Sky Digital and freesat (in the UK and Ireland), Bell TV and Shaw Direct (both in Canada), Canal Digitaal (in the Netherlands), Canal Digital and Viasat (both in Norway, Sweden and Denmark), Cyfra+, Cyfrowy Polsat and n (in Poland), SKY (in New Zealand), NTV Plus (in Russia), Sky Italia in Italy and Digit-Alb (in Albania), offer HDTV to customers as an upgrade. New satellite receiver boxes are usually required to receive HD content.
Video game systems, such as the PlayStation 3 and Xbox 360, and digital set-top boxes such as the Apple TV, and the Netgear Digital Entertainer, can output an HD signal. The Xbox Live Marketplace, iTunes Music Store, and PlayStation Network services offer HD movies, TV shows, movie trailers, and clips for download, but generally at lower bitrates than a Blu-ray Disc.
Most newer computer graphics cards have either HDMI or DVI interfaces, which can be used to output images or video to an HDTV.
Almost all computer graphics cards have standard SVGA jacks which can be used to output images or video to an HDTV's "PC Input" jack.
The optical disc standard Blu-ray Disc (25GB-50GB) can provide enough digital storage to store up to 10 hours of HD video content, depending on encoder settings.
High-definition television the rise in popularity of large screens and projectors has made the limitations of conventional Standard Definition TV (SDTV) increasingly evident. An HDTV compatible television set will not improve the quality of SDTV channels. To display a superior picture, high definition televisions require a High Definition (HD) signal. Typical sources of HD signals are as follows:
Over the air with an antenna. Most cities in the US with major network affiliates broadcast over the air in HD. To receive this signal an HD tuner is required. Most newer high definition televisions have an HD tuner built in. For HDTV televisions without a built in HD tuner, a separate set-top HD tuner box can be rented from a cable or satellite company or purchased.
Cable television companies often offer HDTV broadcasts as part of their digital broadcast service. This is usually done with a set-top box or CableCARD issued by the cable company. Alternatively one can usually get the network HDTV channels for free with basic cable by using a QAM tuner built into their HDTV or set-top box. Some cable carriers also offer HDTV on-demand playback of movies and commonly viewed shows.
Satellite-based TV companies, such as DirecTV and Dish Network (both in North America), Premiere (in Germany), TeleDunya (in Turkey), Sky Digital and freesat (in the UK and Ireland), Bell TV and Shaw Direct (both in Canada), Canal Digitaal (in the Netherlands), Canal Digital and Viasat (both in Norway, Sweden and Denmark), Cyfra+, Cyfrowy Polsat and n (in Poland), SKY (in New Zealand), NTV Plus (in Russia), Sky Italia in Italy and Digit-Alb (in Albania), offer HDTV to customers as an upgrade. New satellite receiver boxes are usually required to receive HD content.
Video game systems, such as the PlayStation 3 and Xbox 360, and digital set-top boxes such as the Apple TV, and the Netgear Digital Entertainer, can output an HD signal. The Xbox Live Marketplace, iTunes Music Store, and PlayStation Network services offer HD movies, TV shows, movie trailers, and clips for download, but generally at lower bitrates than a Blu-ray Disc.
Most newer computer graphics cards have either HDMI or DVI interfaces, which can be used to output images or video to an HDTV.
Almost all computer graphics cards have standard SVGA jacks which can be used to output images or video to an HDTV's "PC Input" jack.
The optical disc standard Blu-ray Disc (25GB-50GB) can provide enough digital storage to store up to 10 hours of HD video content, depending on encoder settings.
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