Magnetic recording

Magnetic recording was established in principle as early as 1898 by Valdemar Poulsen in his telegraphone. Magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetizable medium which moves with a constant speed past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetization like to the signal. A playback head can then pick up the changes in magnetic field from the tape and convert it into an electrical signal.