Reduction of distortion in electromagnetic recording - uses difference current from an extra head without tape passing

摘要

The circuit achieves reduction of distortion like ringing, intermodulation and magnetic material noise due to tape passing over a head, by feedback of a current derived by subtracting the current through a separate head without tape passing over it from that through the head with the tape passing. A potential may be used in the same way with high impedance heads. The method may be used with magnetic tape magnetic discs or magnetic drums. The extra head may be dispensed with an equivalent impedance used instead. The feedback signal may also be used for delayed correction on a separate track.