Abstract: The disclosure relates to a recording and reading apparatus constituting a kind of video reservoir in the home of the consumer. Thanks to a large-capacity storing technique with suitable technical means, broadcasters transmit numerous programs via specific channels and the consumer may control the content of his reservoir (by recording, reading and erasing programs). The invention is applicable to on-demand video in the consumer's home with a video reservoir constituting a video-library that is regularly updated by broadcasters and/or by the consumer himself.

Abstract: The invention relates to a method and device for obtaining an adaptive selection of sets of data stored in a mass memory. The method and device use administrative information stored in a administration memory and related to the data sets, and allow to obtain a classified list of data sets. The adaptive selection may reflect habits of access to the sets of data by a user as well as momentary preferences of the user.

Abstract: The invention relates to a method and a device for obtaining an adaptive selection of sets of data stored in a mass memory (30). The method and the device use administrative information stored in an administration memory (31) and related to the data sets, and allow to obtain a classified list of data sets. The adaptive selection may reflect habits of access to the sets of data by a user (35) as well as momentary preferences of this user. The data sets may for example be songs recorded on a magnetic tape (29).

Abstract: The invention relates to a method of access to data sets stored in a bulk memory. During an access time to a data set, the method provides for reading introduction data and exploiting these. This way the method overcomes the problem of long access times in a bulk memory. The method may notably be used when data sets are arranged sequentially on a sequential data carrier, which is for example the case for songs recorded on a magnetic tape. A device for implementing the method is also defined.

Abstract: The invention relates to a method of access to data sets stored in a bulk memory. During an access time to a data set, the method provides for reading introduction data and exploiting these. This way the method overcomes the problem of long access times in a bulk memory. The method may notably be used when data sets are arranged sequentially on a sequential data carrier, which is for example the case for songs recorded on a magnetic tape. A device for implementing the method is also defined.

Abstract: The disclosure relates to a recording and reading apparatus constituting a kind of video reservoir in the home of the consumer. Thanks to a large-capacity storing technique with suitable technical means, broadcasters transmit numerous programs via specific channels and the consumer may control the content of his reservoir (by recording, reading and erasing programs). The invention is applicable to on-demand video in the consumer's home with a video reservoir constituting a video-library that is regularly updated by broadcasters and/or by the consumer himself.

Abstract: The disclosure relates to a recording and reading apparatus constituting a kind of video reservoir in the home of the consumer. Thanks to a large-capacity storing technique with suitable technical device, broadcasters transmit numerous programs via specific channels and the consumer may control the content of his reservoir (by recording, reading and erasing programs). The invention is applicable to on-demand video in the consumer's home with a video reservoir constituting a video-library that is regularly updated by broadcasters and/or by the consumer himself.

Abstract: A magnetic tape apparatus for the recording and reproduction of signals, including a magnetic tape having plural data tracks running parallel to an edge of the tape; a multi-track reading device including a multi-track playback head configured to read simultaneously plural of the tracks and output signals corresponding to data recorded on the plural tracks; and a housing in which the tape and the reading device are permanently disposed; wherein the tape is adapted for simultaneous recording of data onto plural data tracks of the tape via external recording heads upon the apparatus being connected to an external recording facility.

Abstract: A receiver/recorder for television transmissions whereby continuous recording of television transmission occurs from at least one channel onto a random-access rewritable recording medium. At each of a plurality of predetermined locations a binary code is periodically written to represent a filling of predetermined portions corresponding respectively to the predetermined locations. An indexing device responds to the binary code in order to automatically distinguish between a first in time recorded transmission on the medium from a second in time recorded transmission on the medium at a particular one of the predetermined locations.

Abstract: Disclosed is a system for the recording of data on optic disks. Presently used optic disks, which can be read with lasers working in wavelengths of the visible region (between 0.5 and 0.8 microns), have a maximum surface storage density of the order of one data bit per elementary zone having an area of about one square micrometer. Beyond this limit, the diffraction does not allow the neighboring zones to be distinguished. A means is proposed to considerably increase the storage capacities: in an elementary zone of a layer, an information bit is written not in the form of a point of absorption of a laser light but in the form of a diffraction grating with a determined pitch. Several diffraction gratings, having pitches different from one another, may be superimposed at the same position, enabling the recording, in one and the same zone, of several information bits. The diffraction gratings are made by a periodic local variation of the optic index of the layer.

Abstract: A receiver/recorder of television transmissions is disclosed which operates automatically on a stand-by basis to record continuously television transmissions from at least one channel onto a reusable large capacity recording medium such as a magnetooptic disk. The recording is accomplished without user intervention and the system includes an indexing for distinguishing a recent recording from an older recording which is partially overlapped by the recent recording.

Abstract: A device for the display or projection of images, which has an external output face covered with an abrasion-resistant and transparent coating, said coating constituted in part of an abrasion-resistant layer formed from at least one material selected from the group consisting of adamantane carbon, Y.sub.2 O.sub.3, and indium-tin oxide implanted with oxygen. A display or projection device can be a television tube designed for the display of high-definition transmissions.

Abstract: A magnetic head and a method for producing the magnetic head comprising the steps of:producing a groove in a first face of a substrate;depositing a material having good magnetic characteristics on the walls of the groove;depositing a non-magnetic material in the groove over the material having good magnetic characteristics;machining a second face of the substrate until the non-magnetic material is reached, so as to create a magnetic gap; andbonding a part carrying a magnetic layer onto the first face of the substrate so as to form a magnetic circuit.

Abstract: A method of making a multitrack head consisting in making a first network of grooves in a block of ferrite, filling the grooves with glass, planing down the surface, making a second network of grooves in a second block of ferrite, bonding these two blocks, trueing the base of the first block, depositing poles and making the winding wires go through.

Abstract: A method of simultaneous manufacture of a plurality of planar magnetic heads on a wafer or a slab made of non-magnetic material designed to be cut out to separate each head. The method can be applied to magnetic heads of the type including a micro-gap formed between two magnetic poles, facing a gap defined between two wire-wound ferrite cores. The method consists in depositing said thin layer magnetic poles on a first face of a wafer made of non-magnetic material and in hollowing out, in the face opposite to said wafer, at least one cavity for housing said wire-wound cores so as to obtain a calibrated spacing or a junction between the upper part of each of said wire-wound cores and said thin layer magnetic poles.

Abstract: Integrated single-mode isolator waveguide having a heating means (3) making it possible to increase the efficiency of the isolator (1). The invention also provides for an intermediate layer (5) located between the guide layer (1) and the substrate (2). Application: coupling of laser diodes to operation circuits.

Abstract: Video recording/play-back heads concerning rotating heads subjected to wear are disclosed. The structure of this head is such that the active part of the magnetic head as well as the drum are coated with a wear-resistant layer.

Abstract: A method for achieving the planar surface of an active face for magnetic recording/reading heads. The planar surface of the active face is obtained by grinding, the active face being of the type where, before the grinding operation, the level of the material forming the gap is recessed with respect to the magnetic poles, the method comprising depositing over the recess a thin layer of non-magnetic material with a thickness at least equal to the recess of the gap. The non-magnetive thin layer may then be ground to obtain the planar surface of the active face.

Abstract: A method for fabricating magnetic recording/reading heads. A substrate made of magnetic material is provided with a groove of a predetermined width. The surface of the substrate bearing the groove becomes the active face for the magnetic head. The face of the substrate having the groove is ground, and then filled with a non-magnetic material to form a gap. The filling causes the non-magnetic material to jut out of the groove. The material which juts out is ground off until the level of the substance is reached.

Abstract: In a method for making a thin-film magnetic head, there are stages for depositing hardening material in the plane of the magnetic films and in the neighbourhood of the active surface of the magnetic head. The invention also relates to a magnetic head made according to this method. The invention can be applied to thin-film magnetic heads for magnetic tape read/write devices.