Definição do conceito
ENG] wire recording or magnetic wire recording was the first magnetic recording technology, an analog type of audio storage in which a magnetic recording is made on a thin steel wire. The first crude magnetic recorder was invented in 1898 by Valdemar Poulsen. The first magnetic recorder to be made commercially available anywhere was the Telegraphone, manufactured by the American Telegraphone Company, Springfield, Massachusetts. | 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. | The first wire recorder was invented in 1898 by Danish engineer Valdemar Poulsen, who gave his product the trade name Telegraphone. Wire recorders for dictation and telephone recording were made almost continuously by multiple 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. | Characteristics - Magnetic format - German Reichhalter Reporter W102 wire recorder (c. 1950). Poulsen´s original telegraphone and other very early recorders placed the two poles of the record/replay head on opposite sides of the wire. The wire is thus magnetised transversely to the direction of travel. This method of magnetization was quickly found to have the limitation that as the wire twisted during playback, there were times when the magnetization of the wire was at right angles to the position of the two poles of the head and the output from the head fell to almost zero. | The recorder was improved by placing the two poles on the same side of the wire so that the wire was magnetised along its length or longitudinally. Additionally, the poles were shaped into a "V" so that the head wrapped around the wire to some extent. This increased the magnetising effect and also increased the sensitivity of the head on replay because it collected more of the magnetic flux from the wire. This system was not entirely immune to twisting but the effects were far less marked. | Characteristics - Media capacity and speed - Compared to tape recorders, wire recording devices have a high media speed, made necessary because of the use of the solid metal medium. Standard postwar wire recorders use a nominal speed of 24 inches per second (610 mm/s), making a typical one-hour spool of wire 7,200 feet (approx. 2200 m) long. This enormous length is possible on a spool less than 3 inches (76 mm) in diameter because the wire was very fine, having a diameter of .004 to .006 in (0.10 to 0.15 mm) for later models, an improvement over Poulsen´s Telegraphone of 1898 which used .01-inch (0.25 mm) wire.[9] Smaller 30- and 15-minute lengths of wire were employed by the majority of recorders made after 1945. Some heavy-duty recorders use the larger Armour spools, which can contain enough wire to record continuously for several hours. Because the wire is pulled past the head by the take-up spool, the actual wire speed slowly increases as the effective diameter of the take-up spool increases. Standardization prevented this peculiarity from having any impact on the playback of a spool recorded on a different machine, but audible consequences can result from substantially altering the original length of a recorded wire by excisions or by dividing it up onto multiple spools. | SOURCE: https://en.wikipedia.org/wiki/Wire_recording
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