Abstract: A positioning control system for performing recording/reproducing operations by irradiating an optical beam to predertermined position on an optically recording medium, e.g., magneto-optical disk, includes a photo-detector constituted by at least two-divisional units; and a servo-error signal generating circuit which can generate at least one servo-error signal in accordance with a difference between the detection currents.

Abstract: An optical information recording/reproducing apparatus records information on and/or reproduces information from an optical recording medium and detects a focal error based on a reflected light beam from the optical recording medium. The apparatus includes a composite prism which deflects a part of the reflected light beam to at least two positions excluding a central part of the reflected light beam, and a photodetector device having a plurality of photodetectors which respectively detect the deflected parts of the reflected light beam and output detection outputs. The focal error is detected based on the detection outputs of the photodetector device.

Abstract: A semiconductor memory is installed in a magnetic tape cassette so as to enable electric signals transmitted from the outside of the magnetic tape cassette to be recorded therein or reproduced therefrom. In addition, the magnetic tape cassette includes an output/input terminal by way of which the semiconductor memory is electrically connected to a recording/reproducing unit. With this construction, when the direction of running of a magnetic tape is reversed during a recording or reproducing operation, the recording/reproducing function of the semiconductor memory can be utilized in place of the recording/reproducing function of the magnetic tape with the aid of a changeover signal previously inputted into the magnetic tape at a position, e.g., in the proximity of the end of the magnetic tape. Thus, the occurrence of interruption the recorded/reproduced signals can be prevented by virtue of the substitutive recording/reproducing function of the semiconductor memory.

Abstract: A write-once read-many (WORM) optical disk recorder automatically calibrates its laser to emit a laser beam of a desired power level. While writing data to the WORM disk, a laser test signal is written to a laser checking area termed Automatic Laser Power Correction (ALPC) field. If the emitted laser test signal has a power level outside an acceptable power level window, then inappropriate laser power is indicated. Then, in an error recovery procedure (ERP) the laser power is calibrated in the data sector to be written to using short spaced-apart laser test signals. After successful calibration, data are written to the sector. The test signals appear as burst errors that can be corrected by a suitable error correction code. If such calibration is not successful then a write calibrate sector, WCS, is created and used for an extensive automatic calibration. In the WCS both laser power level is calibrated. The calibration result information is written to WCS for later use.

Abstract: This high-density optical data storage unit comprises a storage medium supported on a mechanically stable substrate, and a read/write arrangement employing a plurality of laser light sources and an interrogation light source. The laser light sources are designed as laser diodes attached to a substrate and optically aligned with an equal plurality of microlenses integrated in a first transparent layer. The read/write arrangement further comprises at least one second transparent layer, and an optional semitransparent conductive coating, said layer or said coating carrying a plurality of particulate protrusions which are also aligned with said diodes and said microlenses, said storage medium and said read/write arrangement being maintained in a mutually parallel alignment with a gap in between having a width of less than 100 nm. The protrusions in combination with the laser light sources produce dints in the medium which are representative of the data to be stored.

Abstract: A data reproducing apparatus reproduces a data recorded or medium which has auxiliary data added to main data subjected to an error correction coding process. The data reproducing apparatus includes a signal processor, a memory, a comparator and a controller. The signal processor separates the main data from the recording data read out from the recording medium to implement an error correction decoding process thereto. The memory means stores the decoded main data from the signal processor. The comparator compares the last data stored in the memory with the inputted main data to the memory. The controller controls write and read operations of the memory and controls the comparison condition of the comparator according to the main data from the signal processor.

Abstract: An optical device has an optical array detector with an array of optical receptors (each receptor is an individual photo detector) that has a greater cross-sectional extent than an impinging light beam. The receptors have respective light receiving areas smaller than the a cross-sectional area of the impinging light beam. A ring lens passes a received light beam to the receptor array. A ring lens refracts a defocused and off-track impinging light beam whereby the optical refractive properties of the ring lens change the cross-sectional form of the received light beam in accordance with status of the light beam. Refraction of the received light beam in the ring lens distorts the beam cross-sectional shape for indicating focus and location errors. Provisions are made for automatic calibration of the impinging beam to a current position of the array detector physical position by the optical device. Optical detection and re-calibration is effected by a digital signal processor.

Abstract: A positioning control system for performing recording/reproducing operations by irradiating an optical beam to predetermined position on an optically recording medium, e,g., magneto-optical disk, includes a photo-detector constituted by at least two-divisional units; and a servo-error signal generating circuit which can generate at least one servo-error signal in accordance with a difference between the detection currents.

Abstract: An optical recording apparatus includes a memory, a recording device, a detector and a controller. The memory stores input data in sequence at a first transmission rate, reads out the stored input data at a second transmission rate which is faster than the first transmission rate, and outputs the data read at the second transmission rate as a recording data in predetermined data units. The recording device adds a cluster connecting sector with a data length long enough to cover a distance to rearrange data through interleaving before and after the recording data in the predetermined data unit and or recording the interleaved data on an optical disc. The detector detects an abnormality of the recording operation and outputs an output signal as an abnormality detected result.

Abstract: An apparatus for recording data signals onto an optical recording medium is disclosed. The apparatus includes a unit for radiating a laser beam onto the optical recording medium, a photo-electric converting unit for converting the laser beam reflected from the optical recording medium into an electrical signal, a first detection unit for detecting whether or not the data signals are recorded on the optical recording medium, a second detection unit for detecting a value of asymmetry based upon an output of the photo-electric converting unit, and a control unit for detecting, prior to recording of the data signals on the optical recording medium, whether or not the data signals are recorded in a region proximate to a region of the optical recording medium in which the data signals are to be recorded.

Abstract: An optical composite unit is provided to receive a light focused by a focusing lens for receiving a light reflected from an optical disc. The optical composite unit comprises a cylindrical lens and side-wedge prisms or side-cylindrical lenses which are provided on both sides of the cylindrical lens. The cylindrical lens has a height including a diameter of the focused light and a width narrower than the diameter, and an axis which is rotated by 45.degree. relative to a long axis of a cylindrical beam formed by the cylindrical lens. The side-wedge prisms or side-cylindrical lenses form side beams separated from the cylindrical beam. The cylindrical beam is for detecting a focus error, and the side beams are for detecting a tracking error.

Abstract: Audio data is stored as a plurality of events on a hard disk, and further header data, i.e., leading portion of the audio data is stored in a header memory prior to reproducing operation. When an event is specified, the header data is read out from the header memory at first. In the meantime, an audio data following the header data is transferred from the hard disk to a buffer memory. The contents of the buffer memory are being read out, even after the header data has been read out from the header memory. With use of an access data table is performed address control for reading out data from the header memory and the hard disk.

Abstract: A recording film of a recording medium has tracks with a track pitch of 1.6 .mu.m. Each track has a land and a groove, and the width of each of the land and groove is about 0.8 .mu.m. The groove and land differ relatively in height by a degree corresponding to (2n-1)/4 (n: a natural number) times the wavelength of the irradiated beam. At the time of reproduction, reflected diffraction beam components reflected from the land and groove are provided with a phase difference .pi.. Thus, a peak of the diffraction beam is concentrated within the range of the NA of an objective lens, with high intensity. As a result, the presence/absence of pits located at a distance less than a diffraction limit, which have not been detected in the prior art, can be detected.

Abstract: An optical head assembly for an optical information reading and reproducing apparatus including a laser for emitting a laser beam directed so as to impinge upon an information carrier disc. Rays of light reflected from the information carrier disc is separated into a reproduction signal detecting beam and two servo signal detecting beams by a path separator prism. The reproduction signal detecting beam enters a reproduction signal detector while the servo signal detecting beams enter an image sensor. The image sensor is so positioned as to cause images of the light beams to assume a substantially equal size. By selecting pixels effective to properly detect focusing and tracking errors, various servo signals can be obtained in dependence on outputs from those pixels selected.

Abstract: An optical pickup is adapted for recording and/or reproducing signals by radiating a light beam from a light source on an optical recording medium via an object lens. The optical pickup includes a light receiving device for receiving a return light from the optical recording medium, and a focusing error detecting unit for detecting an amount of deviation of the focal point along the optical axis. The measurement of a focusing error is based on signals from the light receiving device. The optical pickup further includes an electrostriction device arranged on a path of light outgoing from the light source to the optical recording medium and having a central section and a peripheral section exhibiting a phase difference from each other depending on an applied voltage.Focusing errors may be detected with high accuracy with the optical pickup. A focusing servo device compensates for the focusing error detected by controlling the focal point along the optical axis using a focusing servo device.

Abstract: An optical disc includes a signal recording track spirally formed on the surface of the optical disc, information pits formed on the signal recording track, and a plurality of non-signal regions periodically formed on the signal recording track, wherein no information pit is formed on the non-signal region.

Abstract: The present invention is directed to a magnetic recording and/or reproducing apparatus, in which a reference electrostatic capacity is formed by a wide pattern (23) radially formed over a plurality of recording tracks (22) and a calculation is performed by utilizing this reference electrostatic capacity so as to eliminate the fluctuation of stray capacitance in each of the electrodes (63a) and (63b) of a recording and reproducing head. Thus, the change of stray capacitance occuring due to the drift of temperature, the vibration of interconnection or the like can be eliminated.

Abstract: A recording method and apparatus for an optical disk employs a data format having a fixed pattern sync portion in which a minimum run length of zeros and a maximum run length of zeros are not adjacent to each other. As such, temperature difference caused during recording the optical disk may be made smaller, thermal stress applied upon the medium may be reduced, the deterioration thereof may be restrained, and the repetitive frequency of the medium may be improved.

Abstract: An integrated circuit adapted for use in a data path of a disk storage system of a type wherein data is recorded at different rates depending upon the storage track of the data and includes servo bursts of head positioning signals disbursed throughout the data on all of the tracks. The circuit includes a variable cut off low pass filter that is adjusted both for the rate of data being read and for the rate of the servo bursts when being read. An automatic gain control and a pulse detector are similarly dynamically adjusted in characteristics to fit that of the data and servo bursts when each is being read from the disk. An output of the filter provides both read data and head positioning signals. A write data path is also provided as part of the circuit.

Abstract: A PCM digital audio signal playback apparatus is provided for multiplying a PCM digital audio signal to n times the sampling rate, interpolating extra sampling points with zero signals, and spline-function interpolating with an FIR digital filter. Accordingly, a sound reproduced from the output audio signal of the apparatus will be more natural as compared with common high-cut filtering with a high-cut filter.