Compagnie Internationale Pour L'informatique Cii-honeywell Bull (societe

Compagnie Internationale Pour L'informatique

Michel Helle

Jean-Pierre Lazzari

Jacques Desserre

Jean P Lazzari

A magnetoresistant transducer for reading data present on the tracks of a multitrack magnetic carrier, comprises at least one magnetoresistant element perpendicular to the direction of travel of the data, and first and second magnetic screening means situated at either side of the element. The magnetoresistant transducer comprises deflecting means for deflecting the magnetic field generated by the current flowing through the element. The deflecting means are situated between the latter and the first and second screening means to intercept and deflect the magnetic field lines transmitted by the data items on the track. The deflecting means includes a plurality of mutually parallel thin magnetic blades separated from each other by thin non-magnetic laminations the thickness of which is such that the magnetic coupling between two adjacent laminations is weak. The laminations and magnetoresistances are of anisotropic material and have their axes of easy and difficult magnetization parallel to each other.

Magnetoresistant transducer

A magnetoresistant transduction device for reading coded data comprises a plurality of magnetoresistances (MRI.sub.1 to MRI.sub.5), which are placed in alignment and spaced from a magnetization device (DAI) by means of a grid (GMI) of non-remanent magnetic material, having parallel elements (EFI.sub.1 to EFI.sub.5) situated between the magnetization device and the magnetoresistances and to which the magnetoresistances are secured either directly or by means of a substrate. The parallel elements serve to focus the magnetic field generated by the magnetization device, which may be in the form of a permanent magnet, such that a plurality of n mutually independent magnetic fields is formed, each field being associated with a corresponding magnetoresistance. The transduction device is applicable to the reading of coded data of very low density, utilized more particularly in franking machines.

Magnetoresistant transduction device for reading low density coded data

A magnetic transducer for reading magnetic information from a magnetic support such as a disc or tape which moves before it, comprises a magnetic circuit formed of two thin layer polar pieces having a gap at one end and means coupled magnetically to the circuit for transformation of magnetic flux loss of information into an electric signal. The pole pieces comprise at the level of the gap a central part bounded by two lateral parts spaced such that the magnetic coupling between the central parts is very much less than the magnetic coupling between the corresponding lateral parts of the pieces. The gap disposed between the central parts is larger than the gap of the lateral parts. There is a substantial reduction in Barkhausen noise and parasitic edge effects over conventional transducer constructions which is obtained by making the thickness of the pole pieces of the transducer substantially greater in the area of the geometric path Lpm than at the lateral portions beyond Lpm.

Integrated magnetic transducer

Transducer intended for read/write functions on a magnetic data carrier wherein the data is contained within a plurality of tracks. The transducer includes a magnetic circuit formed by two pole pieces separated by a gap parallel to the carrier, having its larger dimensions perpendicular to the direction of travel of the data of a track and a winding coupled magnetically to this circuit. The larger dimension of the gap varies depending on the nature of the function performed by the transducer. At least one thin layer of magnetic material is deposited across the pole pieces at each outer edge thereof and spaced from each other. The magnetic layers may be deposited in recesses formed in the pole pieces. The pole pieces may be constricted and include thin magnetic layers deposited on the lateral surfaces to channel magnetic flux lines.

Magnetic transducer comprising a gap of variable larger dimension for

Transducer intended for read and/or write functions on a magnetic data carrier wherein the data is contained within a plurality of tracks. The transducer includes a magnetic circuit formed by two pole pieces separated by a gap parallel to the carrier, having its larger dimension perpendicular to the direction of travel of data on a track and a winding coupled magnetically to this circuit. The transducer is characterized in that it comprises means associated with the pole pieces situated at either side of the gap as seen in the direction of its larger dimension, for channelling the magnetic flux emitted by the immediate magnetic surroundings of the track of the carrier read by the transducer.

Magnetic transducer for reading and/or recording of data contained on a

A device for reading an item of information defined by a plurality of different intervals between consecutive elements on a data carrier, and corresponding methods of recognizing an item of information defined by a plurality of different intervals between consecutive pulses of a first pulsed signal. The device includes first and second element detectors arranged for motion relative to the elements on the data carrier, which detectors generate responses to the elements. The element detectors are spaced from each other by a distance e such that the responses to each element generated by said second element detector have a time delay e corresponding to the physical distance e with respect to the responses generated by said first element detector. The device further includes means for comparing the response of said first and second element detectors to produce an output signal representing the item of information. The distance e is selected and the comparison is such that a first interval a is identified when the beginning of a response by said second element detector occurs during a response by said first element detector, and a second interval b is identified when the end of a response by said first element detector occurs during a response by said first element detector.

Method and device for reading coded information in the form of intervals

A magnetic transducer and method of operation is disclosed for removing the effect of interference magnetic fields present when detecting information magnetically coded on a carrier. The transducer is provided with a magnetoresistive compensating element disposed to develop a voltage in response to the interference magnetic fields equal to that developed across a magnetoresistive detecting element; however, the compensating element is positioned out of the magnetic leakage field of the coded information.

Apparatus and method for removing the effect of interference magnetic

Method of producing a magnetic transducer device

A localized-field static magnetizing device consists of a non-magnetic substrate having a magnetic layer thereon that contains a succession of adjoining zones of alternately differing lengths and having magnetic inductions of alternately opposing directions. One of the lengths is much greater than the other and the magnetic layer has a high coercive field.

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Marcq, France

Michel Helle