U.S. Philips Corporation

Other

Willem Frederik Druyvesteyn

Jan Willem Dorleijn

Antonius G Verhulst

Gerrit J Koel

Ulrich E Enz

Frederik Ate De Jonge

Ronaldus Maria Aarts

Jan Haisma

Leon Maria Van De Kerkhof

Jacobus J Ruigrok

Raymond N Veldhuis

Abraham Hoogendoorn

Edmond De Niet

Victor Zieren

Evert H Dekker

Adrianus Wilhelmus Van Den Enden

Franciscus Antonius Kuijpers

Franciscus Antonius Kuipers

Coenraad Jozef Rooijmans

Harm Marinus Booij

An audio-visual arrangement, more particularly, a multi-media terminal, includes a picture screen on which pictures can be displayed. The arrangement further includes a plurality of electro-acoustic converters for reproducing sound that corresponds to audio information generated by the audio signal source. The converters are positioned at regular mutual distances along one side of the picture screen. The ratio of the strength of the control signals applied to the converters has values for which a sound wave concentration is obtained in a listening/viewing area situated dead opposite to the picture screen. With the audio-visual arrangement the nuisance of noise experienced in a living space and/or working space by persons other than the user of the arrangement remains limited. A further reduction of the nuisance can be obtained by a system in which the audio-visual arrangement is combined with means for active noise abatement.

Audio-visual arrangement and system in which such an arrangement is used

The audio signal is divided into frequency sub-bands, the sub-band samples are quantized according to a predetermined quantizing criterion, and the quantized samples in one or more sub-bands are summed with samples of the auxiliary signal in such sub-bands, the auxiliary signal sample in a sub-band having a maximum amplitude less than half the quantization step used in such sub-band. The combined signal, covering the entire frequency band of the audio signal, can be transmitted or recorded on a record carrier. Upon audio reproduction at a receiver only the audio signal will be audible, the auxiliary signal being masked due to the psychoacoustic characteristics of the human auditory system which are unresponsive to low-level noise in the presence of high amplitude sound. The receiver includes a decoder which analyzes the combined signal into the original frequency sub-bands and re-quantizes the sub-band signals using the same quantizing criterion as at the coder. The auxiliary signal is reconstructed by subtracting the quantized signal sample in each sub-band from the non-quantized signal sample therein and combining the non-quantized sub-band signal sample. The auxiliary signal may be a copy inhibit code which serves to inhibit a recorder from recording the audio signal, thus protecting against unauthorized copying.

Coder for incorporating an auxiliary information signal in a digital

Device is provided for reading information from a magnetic recording medium, comprising a SQUID (15), a magnetic yoke formed from two flux guides (3 and 5) and a face (13) for magnetic flux coupling of the SQUID with the magnetic recording medium. The SQUID is provided with connection means (33) for a detection circuit (35).

Superconducting device for reading information from a magnetic recording

A thin-film magnetic head in which the electrically conductive magnetic material of the core is wound directly a number of times around an electrical conductor which ensures the energization of the head presents the advantage that the manufacture can take place by means of exclusively electroplating methods, since in this configuration no insulating layers are necessary between the material of the core and the conductor.

Magnetic head having a core provided on a substrate by means of

A magnetic bubble domain memory system having a first bubble domain path composed of Permalloy pattern elements, and a second bubble domain path composed of a current conductor is disclosed. Separate drives are associated with each of the paths, so the advantages of both types of domain propagation can be combined on a single memory chip. The first and second paths are interconnected, so transfer of domains between paths is possible.

Magnetic domain device

The invention relates to a device for magnetic recording which is provided with a layer of a magnetizable material which is provided on a support and has an easy axis of magnetization which is at least substantially perpendicular to the plane of the layer, which layer is suitable to support magnetic domains having a direction of magnetization which is opposite to the direction of magnetization of the remainder of the layer, the device also comprising a device for producing a magnetization field having a field direction perpendicular to the plane of the layer, said layer being destined to cooperate with a recording medium which is relatively movable with respect to the layer.

Device for the magnetic recording by means of a magnetic strip domain as

A magnetic device comprising at least one thin layer of a magnetizable material having a preferred direction of magnetization which is approximately perpendicular to the surface of the layer in which magnetic domains are generated, maintained and possibly annihilated in the layer. A domain guiding structure which with a given magnetic field substantially in the preferred direction enables the occurrence of two types of magnetic domains. The area of the largest domain is at least 15% and at most 125% larger than that of the other domains. The device also has means which convert one type of domain into the other type of domain.

Magnetic device having domains of two different sizes in a single layer

The invention relates to a plate of magnetic material wherein magnetic domains can be formed and driven along guide structures consisting of discrete elements of magnetizable material, for example, vapor-deposited permalloy. The plate is used as a memory, a number of mainly parallel extending input structures forming paths for the domains between relevant outputs of the memory and relevant inputs of a decoding device. The decoding device comprises delay elements which can each be activated by a specific rotary field sequence. The output of the decoder device has connected thereto a detection element which can thus selectively detect a domain from a predetermined input structure, because exactly for the relevant domain a synchronization exists between a part of the rotary field sequence and the arrival of the relevant domain at a delay element. Therefore, neither further current wires are required for activating the decoding device, nor separate detection lines for detectors which are selective per input structure. A number of simple delay elements which have a compact construction and which can be readily activated are described.

Memory device

A method of manufacturing a magnetizable layer having domains with at most two Bloch walls for a magnetic domain device in which a monocrystalline layer of Y.sub.3.sub.-x La.sub.x Fe.sub.5.sub.-Y Ga.sub.Y O.sub.12, wherein 0.1 .ltoreq. .times. .ltoreq. 0.2 and 1.0 .ltoreq. Y .ltoreq. 1.5 is provided on a monocrystalline substrate and is covered with an SiO-containing layer after which the monocrystalline layer is maintained at a temperature between 300.degree. C and 600.degree. C for some time.

Method of manufacturing a magnetizable layer for a magnetic domain device

A magnetic device comprising a first and a second plate of a magnetic material between which domains are situated. An interaction force occurs between the domains in the two plates. Stable domain positions in a second plate define equally stable domain positions in a first plate. One or both plates can be provided with domain guiding structures. Domain displacement in one plate can control a domain displacement in the other so that a variation in the interaction force is produced.

Magnetic domain logic device

Magnetic device comprising at least one thin layer of a magnetisable material which has a preferred direction of magnetisation substantially at right angles to the surface of the layer. Magnetic domains are produced by a magnetic field which is situated substantially in the plane of the layer and does not change direction and enables similar domains to be produced. The domains are there after maintained by a field normal to the layer. A domain guide structure may also be provided on the layer to move the domains.

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Eindhoven, Netherlands

Willem Frederik Druyvesteyn