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Scanning Tapped Magnetoresistive Sensor

IP.com Disclosure Number: IPCOM000083468D
Original Publication Date: 1975-May-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Lean, EG: AUTHOR [+2]

Abstract

A magnetoresistive sensor of the type discussed in an article entitled Scanned Magnetoresistive Sensors" by E. G. Lean et al, appearing in the IBM Technical Disclosure Bulletin, Vol. 17, No. 12, May 1975 Pages 3751 and 3752, is provided, wherein scanning is achieved through a control circuit (a delay line) which sequentially switches on successive regions of the magnetoresistive sensor.

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Scanning Tapped Magnetoresistive Sensor

A magnetoresistive sensor of the type discussed in an article entitled Scanned Magnetoresistive Sensors" by E. G. Lean et al, appearing in the IBM Technical Disclosure Bulletin, Vol. 17, No. 12, May 1975 Pages 3751 and 3752, is provided, wherein scanning is achieved through a control circuit (a delay line) which sequentially switches on successive regions of the magnetoresistive sensor.

Circuitry, similar to that proposed in the referenced article, is proposed with an additional control gate to sequentially read out the resistive changes. The scheme can be referred to as a scanned, tapped magnetoresistive sensor. The basic geometry is shown in Fig. 1.

A tapped magnetoresistive stripe is fabricated on a proper substrate. The taps are connected, alternately, to the appropriate outputs of a shift register and ground, i.e., even numbered electrodes are connected to the tapped delay line (shift register etc.), while the odd numbered ones are grounded. The even numbered electrodes are also connected, through gates controlled by the shift register, to a common resistance readout display. The output signal is compared with the signal from a set of reference electrodes through a difference amplifier or a bridge. This results in increased sensitivity since aside from the magnetically induced signal, the signal from the reference electrodes is identical to the scanning signal.

The system can be viewed as an array of leaky capacitors,...