|
Advanced Television Systems Committee (ATSC) standards are a set of standards developed by the Advanced Television Systems Committee for digital television transmission over terrestrial, cable, and satellite networks. The ATSC standards were developed in the early 1990s by the Grand Alliance, a consortium of electronics and telecommunications companies that assembled to develop a specification for what is now known as HDTV. ATSC formats also include standard-definition formats, although initially only HDTV services were launched in the digital format. == Background == The high definition television standards defined by the ATSC produce wide screen 16:9 images up to 1920×1080 pixels in size — more than six times the display resolution of the earlier standard. However, many different image sizes are also supported. The reduced bandwidth requirements of lower-resolution images allow up to six standard-definition "subchannels" to be broadcast on a single 6 MHz TV channel. ATSC standards are marked A/''x'' (''x'' is the standard number) and can be downloaded for free from the ATSC's website at ATSC.org. ATSC Standard A/53, which implemented the system developed by the Grand Alliance, was published in 1995; the standard was adopted by the Federal Communications Commission in the United States in 1996. It was revised in 2009. ATSC Standard A/72 was approved in 2008 and introduces H.264/AVC video coding to the ATSC system. ATSC supports 5.1-channel surround sound using the Dolby Digital AC-3 format. Numerous auxiliary datacasting services can also be provided. Many aspects of ATSC are patented, including elements of the MPEG video coding, the AC-3 audio coding, and the 8VSB modulation.〔(TV makers to fight royalties )〕 The cost of patent licensing, estimated at up to per digital TV receiver,〔(FCC Opens Inquiry Into Patent Costs For Digital TVs ), Dow Jones, February 25, 2009〕 has prompted complaints by manufacturers.〔(Amtran affiliate accuses Funai of unfair competition ), Lisa Wang, Taipei Times, Feb 24, 2009〕 As with other systems, ATSC depends on numerous interwoven standards, e.g. the EIA-708 standard for digital closed captioning, leading to variations in implementation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Advanced Television Systems Committee standards」の詳細全文を読む スポンサード リンク
|