Browse Prior Art Database

Cancellation of Feedthrough between Magnetic Heads

IP.com Disclosure Number: IPCOM000083493D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Dent, RF: AUTHOR [+2]

Abstract

Shown is rotor 10 carrying write magnetic head 12 and read magnetic head 14 for a rotating head magnetic tape recorder. In operation, rotor 10 is driven at high speed and tape is wrapped about the rotor so that the path of the magnetic track on the tape is across the tape, rather than along the length of the tape.

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Cancellation of Feedthrough between Magnetic Heads

Shown is rotor 10 carrying write magnetic head 12 and read magnetic head 14 for a rotating head magnetic tape recorder. In operation, rotor 10 is driven at high speed and tape is wrapped about the rotor so that the path of the magnetic track on the tape is across the tape, rather than along the length of the tape.

To reduce feedthrough between the write head 12 and read head 14, shielding is used on the heads and, in addition, the leads to the heads are cross- coupled to further cancel feedthrough. Heads 12 and 14 are constructed of ferrite. The heads are shielded from each other by ferrite pieces located around the sides of the heads and spaced from the heads. These ferrite shields reduce coupling between the heads without distorting the coupling signals. Thereafter external conductive shields on surfaces 15 might be used to further reduce the amplitude of the coupling signals.

The inner core of the rotor 10 has been shown exploded away from the rotor. The core consists of cover plate 16, rotary section 18 attached to the cover plate 16, rotary transformer 20 and fixed section 22. Inner bearings between fixed section 22 and the rotary section 18 are not shown. Lead wires 24 and 26 from write head 12 and read head 14, respectively, pass through plastic collar 28 (transparent plastic as shown). Collar 28 fits in cylindrical slot 30 when the core is in position in the rotor 10. The core is fastened to the rotor via screws 32 (one shows), passing through holes 34 in cover plate 16 and engaging threaded holes
36.

The read and write signals...