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The DTV (an abbreviation of digital television, also called digital broadcast) transition in the United States is the switchover from analog (the traditional method of transmitting television signals) to exclusively digital broadcasting of free over-the-air television programming. The transition from analog to digital television has been described by David Rehr, then president and CEO of the National Association of Broadcasters, as representing "the most significant advancement of television technology since color TV was introduced." For full-power TV stations, the transition went into effect on Friday, June 12, 2009, with stations ending regular programming on their analog signals no later than 11:59 pm local time that day. Under the Digital Transition and Public Safety Act of 2005, full-power broadcasting of analog television in the United States would have ceased after Tuesday February 17, 2009. To help U.S. consumers through the conversion, the Act also established a federally sponsored DTV Converter Box Coupon Program. The DTV Delay Act changed the mandatory analog cutoff date to June 12, although stations were permitted to cease analog transmissions before the new mandatory cutoff date. The legislation was enacted on February 4, 2009, and on February 11, 2009, President Barack Obama signed it into law.〔 The purpose of the extension was to help the millions of households who had not been able to get their coupons for converters because demand for coupons exceeded the funding provided for in the initial bill, leaving millions on a waiting list to receive coupons. Funding for extra coupons was provided by the American Recovery and Reinvestment Act of 2009. By midnight on the original cut-off date of February 17, 2009, 641 stations representing 36 percent of U.S. full-power broadcasters were transmitting exclusively in digital. Analog broadcasting did not cease entirely following the June 12 deadline: under the provisions of the Short-term Analog Flash and Emergency Readiness Act, approximately 120 full-power stations briefly maintained analog "nightlight" service, ending no later than July 12.〔(FCC list of "nightlight" stations )〕 In a separate category, low power television stations will be permitted to continue analog broadcasts for several more years. In September 2010, the FCC announced a proposal to set a hard deadline of 2012 for low power stations to broadcast in digital. On July 15, 2011, the FCC posted the required transition deadlines for low power television. Stations broadcasting on channels 52 to 69 were required to vacate those channels by December 31, 2011, and all analog television transmitters (primarily low-powered (LP), and Class-A low-powered (-CA) stations, and also broadcast translator (TX) translator/repeaters in rural communities) must shut down by September 1, 2015.〔(FCC 11–110 Second Report and Order )〕 On April 24, 2015, it was announced that the conversion date for standard LPTVs and translators still broadcasting in analog has been suspended until further notice, due to economic problems that may arise from the upcoming spectrum auction; however, Class A low-powered stations are still required to convert by the original deadline date of September 1, 2015.〔(FCC Public Notice: "SUSPENSION OF SEPTEMBER 1, 2015 DIGITAL TRANSITION DATE FOR LOW POWER TELEVISION AND TV TRANSLATOR STATIONS", April 24, 2015. )〕 ==Congressional mandate== The Congressional deadline to transition to digital broadcasts was pushed back several times. Congress passed the Telecommunications Act of 1996 with the original transition date of December 31, 2006. The transition to digital television was set back several more times after that. First to December 31, 2008, then to February 17, 2009, and then finally to June 12, 2009. All U.S. full-power analog TV broadcasts were required by law to end on June 12, 2009.〔Section 3002 of the Digital Transition and Public Safety Act of 2005 amending the Communications Act of 1934, section 309(j)(14), codified at .〕 Since March 1, 2007, all new television devices that receive signals over-the-air, including pocket-sized portable televisions, personal computer video capture card tuners, and DVD recorders, have been required to include digital ATSC tuners. Prior to this, the requirement was phased-in starting with larger screen sizes. Prior to the completion of the transition, most U.S. broadcasters were transmitting their signals in both analog and digital formats, though a few are digital-only. Digital stations transmit on another channel, which was assigned to each full-power broadcaster in a three-round digital channel election. The transition from the analog NTSC format to the digital ATSC format was originally required to be completed on February 17, 2009, as set by Congress in the Digital Transition and Public Safety Act of 2005.〔(【引用サイトリンク】title=All-Digital Television Is Coming (And Sooner Than You Think!) )〕 Following the analog switch-off, the FCC has reallocated channels 52 through 69 (the 700 MHz band) for other communications traffic, completing the reallocation of broadcast channels 52–69 that began in the late 1990s. These channels were auctioned off in early 2008, with the winning bidders to take possession of them in June 2009. Four channels from this portion of the broadcast spectrum (60, 61, 68, and 69) will be held for reallocation to public safety communications (such as police, fire, and emergency rescue). In addition, some of the freed up frequencies will be used for advanced commercial wireless services for consumers, such as Qualcomm's planned use of former UHF channel 55 for its MediaFLO service.〔 For U.S. cable television, the FCC voted 5–0 on September 12, 2007 to require operators to make local broadcasts available to their users in analog. This requirement lasts until 2012, when the FCC will review the case again. This was necessary since many cable companies, including major ones like Comcast, have been taking analog channels away from customers. In 2007, a bill in the U.S. Congress called the DTV Border Fix Act was introduced. It would have allowed all television stations within 80 kilometers (50 miles) of the Mexican border, in areas such as San Diego and the Rio Grande Valley, to keep their analog signals active for another five years. The bill passed the Senate but did not pass the House.〔(Bill S.2507 (2007), "DTV Border Fix Act of 2007" ) from OpenCongress.org〕 The SAFER Act was passed by Congress in December 2008 and signed by President Bush just before 25 December. The act has been called the "analog nightlight" act, and allows analog stations on channels that did not conflict with post-transition digital stations the option of leaving their analog transmitters on for an additional 30 days, but only to provide disaster information and information regarding the digital transition. Because the Commerce Department no longer had money to fund additional coupons for converter boxes, and on account of other potential problems, the Barack Obama transition team asked Congress in a January 8, 2009, letter to delay the end of analog TV. The Commerce Department announced January 5, 2009, that the $1.34 billion limit on coupon funding had been reached. Gene Kimmelman of Consumers Union, which wanted a delay, feared older people, those outside cities and the poor needed help. Speaking to a group of area residents as part of a nationwide campaign to persuade people to upgrade, FCC chair Kevin Martin said in Raleigh, North Carolina that a delay was "unlikely". He said it would be "unfair" to all those who have made the effort to switch, and to those who bought the reallocated spectrum that was sold with the understanding analog broadcasts would end February 17, 2009.〔 〕 The delay passed Congress despite this prediction (see below). 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「Digital television transition in the United States」の詳細全文を読む スポンサード リンク
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