Abstract: A processing circuit for an optical reproduction signal provided with a signal generating unit for dividing an optical reproduction signal output from a photo detector and including a plurality of signal components into a plurality of signals having frequency regions corresponding to the respective plurality of signal components and performing current/voltage conversion on the divided optical reproduction signals and a correcting unit for adding the results of the current/voltage conversion of the signal components to correct the results of the current/voltage conversion.

Abstract: A device for recording/reproducing a digital pattern as a sound track of a cinefilm is disclosed. The device includes a cinefilm 1 having an image recording area 2 in which an image is recorded, a perforation section 3 for film feed and digital pattern data recording areas 5 and 6 provided in the vicinity of the perforation section 3. Plural channels of audio data are recorded as the digital patterns in the digital pattern data recording areas.

Abstract: An apparatus for reproducing an optical disc in which a light beam radiated from a light source in an optical pickup is radiated to an optical disc and the return light from the disc is detected by a photodetector provided within the optical pickup for reproducing the information signal recorded on the optical disc. A detection output of the return light from the optical disc as detected by the optical pickup is supplied to a waveform equalizer and to a quantity of skew-calculating circuit for detecting the quantity of skew of the optical disc. An output of the waveform equalizer is further supplied to a demodulating circuit. An output of the quantity of skew calculating circuit is inverted in polarity by a polarity inverting circuit and thence supplied to an integrating circuit an output of which is supplied to a control circuit for controlling a correction device for correcting the disc skew.

Abstract: An optical recording apparatus for recording a pulse signal on a recording medium by using a laser light beam, wherein, as shown in FIG. 4 , for example, a pattern detecting circuit (31) is provided to detect a pulse pattern of a recording signal, and an amplitude of a succeeding signal pulse is decreased in accordance with a control signal from a memory (33) when a pulse interval is not more than a predetermined value to thereby decrease a radiation energy of a laser light pulse, whereby the influence of remaining heat of the recording medium due to a laser light pulse corresponding to a preceding laser light pulse is cancelled to make it possible to record a high-density pulse signal accurately.

Abstract: An optical recording medium has a multi-layer film including a reproducing layer and a recording holding layer magnetically coupled to each other as a recording film. While a readout light is radiated to the optical recording medium for erasing the recording holding layer and the reproducing layer or transcribing signals magnetically recorded in the recording holding layer to the reproducing layer, the signals are converted by photomagnetic effects into optical signals which are read, or an optical recording medium having phase pits changed in reflectance with temperature. While a readout light beam is radiated to the optical recording medium and the reflectance is changed partially within a scanning spot of the readout light beam, the phase pits are read. The minimum pit interval of the recording signals along the scanning direction of the readout light beam is selected to be not more than .lambda./2NA, where .lambda.

Abstract: A method for reproducing a magneto-optical recording medium the recording pits of which are erased or relieved with rise in temperature of the recording medium caused by radiation of a readout light beam or an optical recording medium the reflectance of which is changed with rise in temperature of the recording medium caused by radiation of the readout light beam, in which changes in the size of an effective reproducing region due to the temperature of the recording medium may be inhibited. To this end, when the magneto-optical disc 11, for example, is rotated at a constant angular velocity, a detecting unit 17 is provided for detecting the radial position of the magneto-optical disc 11 and the laser power as well as the external magnetic field is controlled depending on an output of the detecting unit 17 for controlling the size of an effective reproducing region to be constant without regard to the linear velocity at each reproducing position.

Abstract: An optical recording medium has a multi-layer film including a reproducing layer and a recording holding layer, in which, while a readout light is radiated to the optical recording medium for transcribing signals magnetically recorded in the recording holding layer to the reproducing layer, the signals are converted by photomagnetic effects into optical signals which are read. Alternately, an optical recording medium has phase pits formed thereon in accordance with signals and changed in reflectance with temperature, in which, while a readout light beam is radiated to the optical recording medium and the reflectance is changed partially within a scanning spot the readout light beam, the phase pits are read. The track pitch p of pits RP of recording signals in a direction at right angles to the scanning direction of the laser light is set to not more than one-half the spot diameter of the laser light to raise the track density to improve the recording capacity of the recording medium.

Abstract: Disclosed is a method for recording and reproducing sector control information to and from a novel magneto-optical disk to which the so-called erasure type data reproduction method or data-embossed type reproduction method applies. On the magneto-optical disk, sector control information is recorded onto a sector control information recording region at a track recording density lower than that of a data recording region. When data is recorded on the disk at a high track density, the sector control information is recorded in such a manner that the information will not exist on adjacent tracks along the same radials of the disk.

Abstract: This invention is directed to an improvement in a novel magneto-optical disc reproducing method of the record information erasing type or the record information raised or transfer type wherein a technique is employed to prevent the dimension of an actual reproduction region from varying by a change of temperature or linear velocity of a magneto-optical disc. To realize this, reference information is recorded on a magneto-optical disc to reproduce this reference information prior to actual data reproduction to detect the regenerative RF signal level to control a laser power or an external magnetic field so that the regenerative RF signal level becomes equal to a level optimum for reproduction, thus allowing the dimension of an actual reproduction region to be an optimum fixed dimension at all times. At the time of actual reproduction, control is made so that the controlled laser power or external magnetic field is maintained.

Abstract: A method for reproducing a magneto-optical recording medium the recording pits of which are erased or relieved with rise in temperature of the recording medium caused by radiation of a readout beam, or an optical recording medium the reflectance of which is changed with rise in temperature of the recording medium caused by radiation of the readout beam, in which, when the line recording density of the recording medium is changed, the size of the effective reproducing region is controlled to an optimum value conforming to the line recording density to assure a stable reproducing state.

Abstract: A method for reproducing a magneto-optical recording medium the recording pits of which are erased or relieved with rise in temperature of the recording medium caused by radiation of a readout beam, or an optical recording medium the reflectance of which is changed with rise in temperature of the recording medium caused by radiation of the readout beam, in which changes in the size of an effective reproducing region due to the temperature of the magneto-optical or optical recording medium may be inhibited. To this end, a temperature sensor 20 for sensing the temperature of the magneto-optical disc 11, for example, is provided and the laser power or the external magnetic field is controlled depending on the detected temperature by the temperature sensor 20 to maintain a constant size of the effective reproducing region at all times.

Abstract: A method and apparatus for recording and reproducing information onto and from a magneto-optic recording medium is disclosed. The magneto-optic recording medium has at least a reproducing layer and a recording layer. A recording optical head records information on the magneto-optic recording medium. A reproducing optical head has a reading light beam for reading information recorded in a region within a spot of the reading light beam by magneto-optic effect by changing a state of magnetization of the reproducing layer and at the same time irradiating the recording medium with the light beam. A wavelength of the recording light beam emitted by the recording optical head is substantially smaller than a wavelength of the reading light beam emitted by the reading optical head. A minimum ratio of the wavelength of the recording light beam to that of the reproducing light beam is 1:3.

Abstract: The method of the present invention comprises detecting a recording pattern, which is different for each tract, in each of track groups consisting of a predetermined number N or tracks recorded in advance on an optical disk(1), generating a tracking signal S.sub.ET whose signal level changes on the positive and negative sides of a target track T.sub.0 as the center, and moving the optical spot to the target track T.sub.0 on the basis of this tracking signal S.sub.ET. In this manner, it becomes possible to prevent uncontrollable movement of the optical spot and align the optical spot to a desired recording track within a short period of time.