DIGITAL TELEVISION |
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DTV can be used to carry more channels in the same amount of bandwidth than analog TV (6 MHz or 7 MHz in Europe) and to receive high-definition programming. The digital signal eliminates common analog broadcasting artifacts such as "ghosting", "snow", and static noises in audio. However, when the signal is transmitted at a too low data rate DTV replaces these artifacts with new MPEG compression artifacts, such as "blocking", and may fail to work entirely in situations where analog television would have produced an impaired but watchable picture. Depending on the sophistication and level of the error correction defined by the technical standard that the broadcaster complies with, DTV may either work perfectly or not work at all.
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INTERNET |
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The Internet, or simply the Net, is the publicly accessible worldwide system of interconnected computer networks that transmit data by packet switching using a standardized Internet Protocol (IP). It is made up of thousands of smaller commercial, academic, domestic, and government networks. It carries various information and services, such as electronic mail, online chat, and the interlinked Web pages and other documents of the World Wide Web.
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PHOTOGRAPHY |
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Photography is the process of making pictures by means of the action of light. It involves recording light patterns, as reflected from objects, onto a sensitive medium through a timed exposure. The process is done through mechanical, chemical or digital devices commonly known as cameras.
The word comes from the Greek words φως phos ("light"), and γραφις graphis ("stylus", "paintbrush") or γραφη graphê, together meaning "drawing with light" or "representation by means of lines" or "drawing." Traditionally, the product of photography has been called a photograph. The term photo is a convenient abbreviation. Many people also call them pictures. In digital photography, the term image has begun to replace photograph. This term is neither more nor less correct than photograph, either in film or digital photography. (The term image is traditional in geometric optics.)
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