Browse Prior Art Database

Magnetoresistive Type Hand Scanning Magnetic Transducer

IP.com Disclosure Number: IPCOM000076192D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Hagopian, JJ: AUTHOR

Abstract

This electromagnetic transducer 10 affords higher sensitivity and signal-to-noise ratio.

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Magnetoresistive Type Hand Scanning Magnetic Transducer

This electromagnetic transducer 10 affords higher sensitivity and signal-to- noise ratio.

Only the internal components and wiring are shown. Conventional casing structure is contemplated for packaging a hand-held probe unit. A substrate 12 of nonmagnetic material has a plurality of thin magnetoresistive film strips 14-17 deposited thereon. The material may be conventional and comprise 81% nickel and 19% iron. One strip 14 is arranged for sensing the vertical field component the magnetic flux of a record medium 20, for example, a recorded magnetic stripe, or printed magnetic bar coded information. Another strip 17 is arranged for sensing any ambient magnetic field which is also acting on the strip 14. The other two strips 15, 16 are used to make up an electric bridge circuit; they may be replaced by a pair of matched resistors which are not magnetoresistive.

Either alternating or direct exciting current is applied between terminal 22 and terminal 24, across one diagonal of the bridge circuit. If alternating current is used, the frequency should be at least twice the bit rate resulting from the scanning operation.

The output signal is derived across the other diagonal of the bridge circuit between terminals 26 and 28.

The horizontal field component of the recording may be sensed with a magnetic core structure of generally H-shape (as for two ring-heads arranged back-to-back). The legs of the core are interrupt...