HDTV
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What does HDTV stand for?
HDTV stands for high-definition television, a digital broadcasting standard that provides superior picture and audio quality compared to traditional standard-definition television (SDTV).
HDTV offers video resolutions as high as 1,920 by 1,080 pixels, significantly greater than SDTV. The lowest high-resolution standard is 720p (1,280 by 720), with higher resolutions including 1080i (1,920 by 1,080) and 1080p, combining progressive scan and a greater pixel count.
HDTV's picture mimics the wide-screen shape of motion pictures, with a 16:9 aspect ratio, and is capable of broadcasting audio in 5.1-channel surround sound.
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How is HDTV different from standard TV?
HDTV (high-definition television) is a digital broadcasting standard that provides superior picture and audio quality compared to traditional SDTV (standard-definition television).
HDTV offers video resolutions as high as 1,920 by 1,080 pixels, far greater than SDTV. The lowest high-resolution standard is 720p (1,280 by 720), while the next higher is 1080i (1,920 by 1,080). The highest is 1080p, which combines the progressive scan of 720p with the greater pixel count of 1080i.
HDTV's picture mimics the wide-screen shape of motion pictures, with a rectangular aspect ratio of 16:9, whereas SDTV typically appears in the nearly square 4:3 aspect ratio. Because it is digital, HD allows multicasting, so a single television station can broadcast different programs on several channels simultaneously. HDTV can broadcast audio in 5.1-channel surround sound, which is more nuanced than conventional stereo.
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Why is picture and sound quality better with HDTV broadcasting?
HDTV broadcasting offers superior picture and audio quality compared to traditional standard-definition television (SDTV) due to its digital broadcasting standard. HDTV uses digital transmission instead of analog radio waves, allowing for higher video resolutions, up to 1,920 by 1,080 pixels, far exceeding SDTV. HDTV has a rectangular aspect ratio of 16:9, mimicking widescreen motion pictures, and is capable of broadcasting audio in 5.1-channel surround sound, providing a more nuanced audio experience than conventional stereo. Digital transmission enables multicasting, allowing a single station to broadcast multiple programs simultaneously.
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What equipment do you need to watch HDTV broadcasts?
To watch HDTV broadcasts, you'll need specific equipment to receive and display the high-definition signal.
First, you need an HDTV set with a digital display screen, such as an LCD (LED) TV, as traditional cathode-ray tube (CRT) televisions have become obsolete.
To receive the broadcast, you'll need either a cable or satellite connection or an antenna for over-the-air broadcasts. If you subscribe to a premium cable service, a cable converter box might be required to decrypt the signal.
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How does digital broadcasting help deliver HDTV signals?
Digital broadcasting helps deliver HDTV signals through digital transmission, which emerged in the 1990s. Digital broadcasting compresses the bit rates to fit digital broadcasts into existing channels by eliminating redundant picture information from the signal. This compression uses the MPEG-2 standard for digital video signals. HDTV offers video resolutions up to 1,920 by 1,080 pixels, significantly higher than standard-definition TV (SDTV). Digital signals also allow multicasting, where multiple programs can be broadcast on a single channel simultaneously.
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What changes did TV stations have to make to broadcast in HDTV?
To broadcast in HDTV, TV stations had to switch from analog to digital signals, a change mandated by the U.S. government, with a final deadline of June 12, 2009. This conversion, coupled with HDTV's need for digital display screens, rendered traditional cathode-ray tube (CRT) television sets obsolete.
Broadcasters also had the option to transmit multiple standard-definition programs over a single channel, a process known as multicasting. Furthermore, digital transmission opened the door for smart TV capabilities, potentially transforming home receivers into computers.
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HDTV, a digital broadcasting standard that offers picture and audio superior to that of traditional standard-definition television (SDTV).
By the early 1990s, long-running international development efforts aimed at creating a higher-quality television signal had converged on digital transmission in place of traditional analog radio waves. In 1998 John Glenn, a former astronaut and then U.S. senator, went on a spaceflight with the launch broadcast live in high definition to specially equipped museums, electronics stores, and other locations. By the middle of the next decade, many broadcast networks and cable outlets offered HDTV channels, and HDTV sets were widely available to consumers.
HDTVâbroadcast by cable or satellite or over the ultrahigh frequency (UHF) portion of public airwaves at a bandwidth of 6 megahertz (MHz)âoffers video resolutions as high as 1,920 by 1,080 pixels (1,920 columns by 1,080 rows), many times greater than that of SDTV. The lowest high-resolution standard is 720p, or 720 progressive scan, for resolutions of 1,280 by 720 in which all the rows are refreshed together in each display cycle (typically 50 or 60 Hz, depending on country, though televisions with faster display cycles have been introduced). The next higher resolution is 1080i, or 1080 interlaced scan, for resolutions of 1,920 by 1,080 in which only alternate rows are refreshed in each cycle. While 720p gives slightly better images than 1080i for scenes with a great deal of motion, 1080i gives slightly greater details, which result in crisper static images. Finally, 1080p combines the progressive scan of 720p with the greater pixel count of 1080i.
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HDTVâs picture mimics the âwide-screenâ shape of motion pictures, with a rectangular aspect ratio of 16:9; SDTV typically appears in the nearly square 4:3 aspect ratio. Because it is digital, HD allows multicasting, whereby a single television station may broadcast different programs on several channels simultaneously. HDTV is capable of broadcasting audio in 5.1-channel âsurround sound,â which is more nuanced than conventional stereo.
The U.S. government mandated that all full-power over-the-air television stations switch completely from analog to digitalâthough not necessarily HDâsignals on February 17, 2009, but in early February the deadline was extended to June 12, 2009. This conversion, along with HDTVâs requirement of a digital display screen, drove traditional cathode-ray tube (CRT) television sets into obsolescence. The most common type of HDTV is a liquid crystal display (LCD) backlit by light-emitting diodes, called an LED TV.