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A video tape recorder (VTR) is a tape recorder designed to record video material on magnetic tape. The first practical video tape recorder, using transverse tape head scanning, was developed by Ampex Corporation in 1956. The early VTRs were reel to reel devices which recorded on individual reels of 2 inch (5.08 cm) wide magnetic tape. They were used in television studios, serving as a replacement for motion picture film stock and making recording for television applications cheaper and quicker. Beginning in 1963, videotape machines made instant replay during televised sporting events possible. Improved formats, in which the tape was contained inside a videocassette, were introduced around 1969; the machines which play them are called videocassette recorders. Agreement by Japanese manufacturers on a common standard recording format, so cassettes recorded on one manufacturer's machine would play on another's, made a consumer market possible, and the first consumer videocassette recorder was introduced by Sony in 1971. == History == One of the first efforts at video recording was the Vision Electronic Recording Apparatus, a high speed multi-track machine developed by the BBC in 1952. This machine used a thin steel tape on a 21-inch (53.5 cm) reel traveling at over 200 inches (510 cm) per second. Despite 10 years of research and improvements, it was never widely used due to the immense length of tape required for each minute of recorded video. Many other fixed-head recording systems were tried but all required impractically high tape speed. It became clear a practical video recording technology depended on finding some way of recording the wide-bandwidth video signal without the high tape speed required by linear-scan machines. The solution was the transverse-scan technology invented by Ampex around 1954, in which the recording heads are mounted on a spinning drum and record tracks in the transverse direction, across the tape. This technique recorded a much higher density of data per centimeter of tape, allowing a lower tape speed of 15 inches per sec. to be used. The Ampex VRX-1000 became the world's first commercially successful videotape recorder in 1956. It used the 2" Quadruplex format, using two-inch (5.1 cm) tape. Because of its price, the Ampex VRX-1000 could be afforded only by the television networks and the largest individual stations. In 1963, Philips introduced its EL3400 1" helical scan recorder (aimed at the business and domestic user) and Sony marketed the 2" PV-100, its first reel-to-reel VTR intended for business, medical, airline and educational use. The Telcan, produced by the Nottingham Electronic Valve Company and demonstrated on June 24, 1963,〔Albert Abramson, ''The History of Television, 1942 to 2000'' (McFarland, 2003) p99〕 was the first home video recorder. It could be bought as a unit or in kit form for £60. However, there were several drawbacks: it was expensive, not easy to put together, and could record only 20 minutes' output at a time in black and white. The Sony model CV-2000, first marketed in 1965, was its first VTR intended for home use and was based on half-inch tape. Ampex and RCA followed in 1965 with its own reel-to-reel monochrome VTRs priced under US $1,000 for the home consumer market. The EIAJ format was a standard half-inch format used by various manufacturers. EIAJ-1 was an open-reel format. EIAJ-2 used a cartridge that contained a supply reel, but not the take-up reel. Since the take-up reel was part of the recorder, the tape had to be fully rewound before removing the cartridge, a slow procedure. The development of the videocassette followed the replacement by cassette of other open-reel systems in consumer items: the Stereo-Pak 4-track audio cartridge in 1962, the compact audio cassette and Instamatic film cartridge in 1963, the 8-track cartridge in 1965, and the Super 8 home movie cartridge in 1966. Before the invention of the video tape recorder, live video was recorded onto motion picture film stock in a process known as telerecording. Although the first Quadruplex VTRs recorded with good quality, the recordings could not be slowed or freeze framed, so telerecording processes continued to be used for about a decade after the development of the first VTRs. 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「video tape recorder」の詳細全文を読む スポンサード リンク
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