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|magnetic recording |
The recording of a signal, such as sound or computer instructions, in the form of a magnetic pattern on a magnetizable surface, such as tape or a disk coated with metal oxides. In the recording process, small electromagnets are used to convert an electrical signal into a magnetic one that magnetizes that surface. The value of the signal at any given point corresponds to the degree and polarity of magnetization of the surface at a corresponding point. During playback, the opposite process occurs, and the magnetic fields along the surface are converted into electrical signals for further processing.
method of preserving sounds, pictures, and data in the form of electrical signals through the selective magnetization of portions of a magnetic material. The principle of magnetic recording was first demonstrated by the Danish engineer Valdemar Poulsen in 1900, when he introduced a machine called the telegraphone that recorded speech magnetically on steel wire.