Abstract: An optical record carrier having an information track structure on a surface thereof, one or more of the tracks being pre-recorded with standard information pertaining to a particular class of information of common use to an undefined number of users. Portions of one or more tracks which are not so pre-recorded are covered with a layer of optically recordable material, for recording thereon of information of the aforesaid class which completes or updates the standard information in whole or in part.

Abstract: A record carrier for information, for example video and/or audio information, in the form of a disk-shaped carrier substrate provided with an optical structure in accordance with the information is described. By making the optical structure radiation-reflecting and the substrate radiation-transmitting, while the surface of the substrate more remote from the optical structure forms both the entrance face and the exit face for the read radiation, and by coating a surface of the optical structure more remote from the substrate with an additional layer, a simple record carrier is obtained which is well protected against dust particles and damage.

Abstract: An optical information recording and/or read system comprises an optically readable record carrier (1) and an optical read and/or recording apparatus (FIG. 2). The record carrier (1) is provided with substantially concentric tracks (2). The record carrier (1) is divided into sectors (4). In the tracks of each sector address information is recorded by means of prior recorded radially juxtaposed address information patterns (8). The read and/or recording apparatus (FIG. 2) comprises a driver (20, 21) for rotating the record carrier (1), scanner (23, 25) for scanning the tracks (3) with a radiation beam (2) for the purpose of recording and/or reading, a closed-loop tracking system (23, 26) for keeping the radiation beam (24) aimed at the track (6) to be scanned, and an angular-position-detection system (23, 26, 27) for determining the angular position of the record carrier (1).

Abstract: Apparatus and methods for remodulating digital luminance and color difference components for display as PIP information, or together with other composite video components for multi-PIP and test pattern applications are disclosed. A digital encoder is used for conducting a digital quadrature modulation on the color difference components and for digitally adding the luminance signal thereto prior to the converting of the remodulated information into an analog format. Preferably, the digital video information output by the encoder is in the form Y1+(R-Y)1, Y1 +(B-Y)1, Y2-(R-Y)1, Y2-(B-Y)1, Y3+(R-Y)2. Y3+(b-Y)2, Y4 -(R-Y)2, . . . , where Y is the luminance component, R-Y and B-Y are color difference components, and where the numbers index received samples of the video components with the luminance component being sampled at twice the frequency of the color difference components.

Abstract: Apparatus is described for pre-forming a relief structure of optically detectable servo-track portions and sector addresses on the recording layer of a record-carrier body, the maximum transverse width of the servo-track portions and sector addresses being the same and exceeding approximately 1/2 the track period P.sub.r but being less than approximately 3/4 P.sub.r. This enables the servo-track portions to be tracked in an optimum manner by a radiation beam and the sector-addresses and the information recorded by the user produce a read-out signal of high amplitude.

Abstract: An optical scanning device which includes a radiation source, a mirror objective an a radiation-sensitive detection system, the mirror objective being a transparent body having a radiation window and a reflector symmetrical therewith on each of two opposed surfaces of such body. First diffraction elements are respectively arranged on the first and second radiation window and the second reflector, whereby radiation directed through the first window is focussed to a scanning spot on an information plane and radiation from such plane after a second passage through the mirror objective includes a number of diffracted beams directed on the radiation detection system. The diffracted beams enable detection of tracking errors and focussing errors of the scanning spot relative to tracks on the information plane.

Abstract: A method of longitudinally severing a longitudinally symmetrical annular core of ferromagnetic material into two parts. By means of a laser, two lines of recesses are inscribed in the surface of the annular core substantially in the longitudinal direction. The recesses are shaped so that the resulting weakening of the annular core along the lines of recesses causes it to spontaneously fracture into two parts along such lines.

Abstract: A record carrier is described having an optically readable information structure comprising information areas arranged in information tracks and spaced from each other by intermediate areas. The information areas have a first, comparatively large, phase depth and the intermediate areas have a second, comparatively small, phase depth thereby providing an optimum information signal and an optimal tracking signal during reading.

Abstract: A telecommunication exchange which provides secure access by only authorized terminals to a computer connected to the exchange. The control processor in the central control unit of the exchange is programmed to provide a "call-back" procedure in respone to a request from a terminal for access to the computer. The calling terminal enters by tone or pulse dialing, the address (such as a telephone number) of the computer together with an identification code. The control processor compares such identification code with a list stored therein of authorized identification codes and authorized terminals addresses corresponding thereto. If the identification code is authorized, the control processor causes a confirm signal to be transmitted from the exchange to the requesting terminal signifying to the user of such terminal to release its line, after which a ringing signal is transmitted to the authorized terminal address corresponding to the authorized code.

Abstract: A method of, and a device for, reducing the magnetic stray field generated in the vicinity of the faceplate of a cathode ray tube by the deflection current in the deflection coils of the tube. A current loop (4) is arranged at a distance from the deflection coils and is supplied with current having a time function substantially coinciding with the time function of the deflection current. The stray field is thereby neutralized to a large extent in a region extending beyond the position of the current conductor (4) in a direction away from the faceplate.

Abstract: Optical record carrier scanning apparatus including a source of radiation which is tunable to produce different wavelengths of a radiation beam and an optical assembly for forming the radiation beam into a spot for scanning information tracks on the record carrier. The optical assembly includes a diffraction grating which diffracts the beam so that only a selected diffraction order sub-beam thereof is formed into the scanning spot, the diffraction angle of such sub-beam and consequently the position of the scanning spot relative to the track being scanned being variable by variation of the wavelength of the radiation beam. A periodic transverse variation of spot position can thus be produced entirely optoelectronically, for producing a tracking error signal to control the scanning spot to remain centered on the information track.

Abstract: Either one of the fields of an interlaced television signal is designated as top field as indicated by a first selector signal. The presence of a second selector signal indicates bottom field. A regenerated vertical synchronization signal is furnished for the first horizontal synchronization signal following vertical synchronization in top field. This regenerated vertical synchronization signal resets a counter which counts horizontal synchronization signals repetitively to a count of five. A second regenerated vertical synchronization signal is furnished when the count of five is reached following the vertical synchronization signal of bottom field. The counter is reset by each first regenerated vertical synchronization signal. When a synchronization signal which would normally be designated top field occurs within a predetermined window around horizontal synchronization, the subsequent field is designated top field, i.e. a field switch takes place.

Abstract: A method and apparatus are described for recording a binary information signal (FIG. 2a) on a record carrier (1) having an information layer (2) whose optical properties are modified upon heating. An information pattern corresponding to this information signal (FIG. 2a) is obtained in that the record carrier 1 is moved relative to an optical system (3) for focussing a radiation beam (4) on the information layer (2), a subsequent recording mark (5) being written on the information layer (2) in selected time intervals (.tau.) by locally heating the information layer by means of the radiation beam (4). The amount of radiation energy (E) applied in a selected time interval depends on the position of the selected time interval (.tau.) in the sequence of consecutive selected time intervals (.tau.). This provides compensation for the influence of the radiation energy (E) applied in the preceding time interval (.tau.) on the temperature at the location of the recording mark (5) to be written in the time interval (.

Abstract: Finite audio and video signals are subjected to some digitalizing encoding format and converted into blocks of audio and video words, respectively. For transmission of these blocks via a compact disc, the words are arranged in packets. Each packet has a packet header and a data field. Such a data field comprises either only audio words or only video words. The packet heater indicates whether the associated data field comprises audio or video words. In order to transmit only changes in the picture in the case of, inter alia, quasi-stationary pictures, each block of video words is divided into a number of sub-blocks and an operational code is added to the beginning of each sub-block. This defines, inter alia, picture elements and the sub-block itself gives video words for these pictures elements.

Abstract: A system for recording and/or reading an information signal (V.sub.i) on an elongated track (4) of an optically readable record carrier (1). A position-identifying signal (V.sub.p) which is synchronous with a clock signal is recorded on the track 4 by modulating the transverse excursion of the track, the signal V.sub.p indicating the instantaneous position along the track at which the information signal V.sub.i is located. The frequency band of the position-identifying signal V.sub.p is situated substantially outside the frequency band of the information signal V.sub.i. In manufacturing such a record carrier, the deflection of a recording beam of radiation in a direction substantially transverse to the track is modulated by the position-information signal V.sub.p.

Abstract: A mobile radio facility for installation in a motor vehicle which already includes a junction cable extending from a location in the trunk to a location in the passenger compartment, terminating at each end in a plug connector. The facility includes a radio unit which can be installed in the trunk and plug connected to the vehicular cable, and one or more peripheral units in the passenger compartment such as a micro-telephone, control panel and/or portable telephone. Each peripheral unit has at least a pair of identical plug-in terminals providing identical connections thereto. The facility also includes a plurality of additional junction cables, one of which is plug-connected at one end to the vehicular cable and at the other end to a plug-in terminal of one of the peripheral units. Each of the remaining cables is plug-connected at each end to a plug-in terminal of different peripheral units so as to establish a sequential order of interconnection of all such units to the vehicular cable.

Abstract: Upon receipt of an interlaced television signal, the field generator generates a first selector signal arbitrarily selecting one of the fields as top field and a second field selector signal selecting the other as bottom field. The received television signal is entered into memory under control of the field selector signals. When readout from the memory occurs on the same line that is currently being recorded, the same field selector signal is maintained for another field, effectively switching the top and bottom assignments.

Abstract: A method of and apparatus (FIG. 4) for recording an information signal (Vi), in particular an EFM-modulated signal, are revealed, which information signal comprises time-code signals which alternate with first time-synchronization signals. The record carrier (1) which is employed is provided with a preformed servo track (4) which exhibits a periodic track modulation whose frequency is modulated in conformity with the position-information signal (FIG. 2). The position-information signal (FIG. 2) comprises position-code signals (12) which alternate with position-synchronization signals (11). During recording a fixed phase relationship between the time-synchronization signals and the position-synchronization signals (11) is maintained, so that the portion (141) of the servo track (4) in which the time-synchronization signals are recorded are situated at fixed positions relative to the servo-track portions (140) which represent the position-synchronization signals (11).

Abstract: For a wide aspect ratio display, the main panel component and augmentation panel component at the transmitting end into which the horizontal line signals of hte source were decomposed are reconstituted at the receiving end by joining the previously separated components together at stitch points. In order to decrease the visibility of the stitch points in the reconstituted wide aspect ratio display, the location of the stitch point in each line is varied. The variation may be on a frame-to-frame bais or on aline-to-line basis. The latter is the preferred form, the line-to-line variation being, preferably, a random variation.

Abstract: In an optical disc playback unit a focused laser beam recovers audio and video information recorded on a spiral track on the disc surface for display. A pivotably mounted mirror in optical communication with the beam is actuated to assist the beam in radially following the spiral track during normal playback. Upon command of an external controller, the mirror actuator mechanism is actuated by a rapid track access circuit to cause the beam to be radially relocated from a present playback position on the disc to an alternate predetermined branch location, causing the display to change. A tracking circuit, responsive to movement of the beam over intervening tracks, causes the rapid track access circuit to decelerate the mirror as the beam approaches the branch location to provide accurate repositioning to the branch location.