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Wire recording is a type of analog audio storage in which a magnetic recording is made on thin steel or stainless steel wire.〔 The wire is pulled rapidly across a recording head which magnetizes each point along the wire in accordance with the intensity and polarity of the electrical audio signal being supplied to the recording head at that instant. By later drawing the wire across the same or a similar head while the head is ''not'' being supplied with an electrical signal, the varying magnetic field presented by the passing wire induces a similarly varying electric current in the head, recreating the original signal at a reduced level. Magnetic wire recording was replaced by magnetic tape recording, but devices employing one or the other of these media had been more or less simultaneously under development for many years before either came into widespread use. The principles and electronics involved are nearly identical. Wire recording initially had the advantage that the recording medium itself was already fully developed, while tape recording was held back by the need to improve the materials and methods used to manufacture the tape. ==History== The first wire recorder was a Valdemar Poulsen Telegraphone of the late 1890s. Wire recorders for dictation and telephone recording were made almost continuously by various companies (mainly the American Telegraphone Company) through the 1920s and 1930s, but use of this new technology was extremely limited. Dictaphone and Ediphone recorders, which still employed wax cylinders as the recording medium, were the devices normally used for these applications during this period. The brief heyday of wire recording lasted from approximately 1946 to 1954. It resulted from technical improvements and the development of inexpensive designs licensed internationally by the Brush Development Company of Cleveland, Ohio and the Armour Research Foundation〔Morton (1998) (journal article), p. 213.〕 of the Armour Institute of Technology (the IIT Research Institute of the Illinois Institute of Technology ). The two organizations (Brush and Armour) licensed dozens of manufacturers in the U.S., Japan, and Europe. Examples are Wilcox-Gray,〔 Pierce,〔 Webcor,〔 and Air King.〔 The popularity even encouraged Sears to provide a model,〔Sears (circa 1949) (pamphlet manual).〕 and some authors to prepare specialized manuals.〔Sams (1947) (book).〕〔Hickman (1958) (book).〕〔Judge (1950) (manual).〕 These improved wire recorders were not only marketed for office use, but also as home entertainment devices that offered advantages over the home disc recorders which were becoming increasingly popular for making short recordings of family and friends and for recording excerpts from radio broadcasts. Unlike home-cut phonograph records, which can accommodate only a few minutes of audio on each side, the steel wire can be repeatedly rerecorded and allowed much longer uninterrupted recordings to be made. The earliest magnetic tape recorders, not commercially available in the U.S. until 1948, were too expensive, complicated, and bulky to compete with these consumer-level wire recorders.〔Morton (1998) (journal article).〕 During the first half of the 1950s, however, tape recorders which were sufficiently affordable, simple, and compact to be suitable for home and office use started appearing and they rapidly drove wire recorders from the market.〔〔〔The Morton (1998) article, p. 213, states: "But the decline of the wire recorder was as sharp as its rise, and by the early 1950s, the device had been completely displaced by the tape recorder, a machine with similar operating principles but a different recording medium."〕 Exceptionally, the use of wire for sound recording continued into the 1960s in Protona's Minifon miniature recorders, in which the importance of maximizing recording time in a minimum of space outweighed other considerations. For any given level of audio quality, the nearly hair-thin wire had the advantage that it was a much more compact storage medium than tape. The Minifon wire recorder was designed for stealth use and its accessories included a microphone disguised as a wristwatch.〔(cryptomuseum.com ) Retrieved 2011-07-15.〕〔Description and photos of the late-model transistorized Minifon Special miniature wire recorder, introduced in 1961, can be found at www.cryptomuseum.com.〕 Wire recording was also used in some aircraft cockpit voice recorders and flight data recorders beginning in the early 1940s, mainly for recording radio conversations between crewmen or with ground stations. Because steel wire was more compact, robust, and heat-resistant than magnetic tape (which is plastic-based), wire recorders continued to be manufactured for this purpose through the 1950s and remained in use somewhat later than that. There were also wire recorders made to record data in satellites and other unmanned spacecraft of the 1950s to perhaps the 1970s. 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「Wire recording」の詳細全文を読む スポンサード リンク
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