Abstract: An optical disk according to the present invention has data recording tracks of lands and grooves. Each of the data recording tracks has a length corresponding to a revolution of the disk and includes a plurality of track sectors. The data recording tracks of lands and grooves are connected alternately to each other so as to form a continuous data recording spiral. Each of the track sectors has a preformatted identification signal part for representing sector address data and has a data recording part for recording data. The identification signal part has the first address data region and the second address region. The first address data region and the second address data region are shifted by the same predetermined distance from the center of a groove track oppositely in the radial direction of the disk.

Abstract: An object of this invention is to provide a method for processing signals for an optical disc device and an optical disc device for immediately determining the on-track state of a main beam light impinging on an optical disc including land areas on which information is recorded, said optical disc being track-formatted to have a double spiral structure. In recording or reproducing information on or from the land areas while track-controlling a first reflected light (MB) based on a second reflect light (SB1) and a third reflect light (SB2), the phases of a sum signal (SUM) and a difference signal (DIFF) between a first push-pull signal (PP1) obtained from an output from a first split photo conductor (21) and a second push-pull signal (PP2) obtained from an output from a second split photo conductor (23) are compared to determine from the mutual phase relationship which land area is providing the first reflected light (MB).

Abstract: An optical recording/reproducing apparatus for recording/reproducing information on a medium including a light source, an optical system for focusing and irradiating a light beam generated by the light source on the medium, a photodetector for detecting a reflected beam from the medium, and a circuit for reproducing information by using a signal from the photodetector. The medium includes a substrate with grooves and lands alternately formed on the substrate in a radial direction. The grooves and the lands both serve as recording tracks with the recording tracks being divided into recording units in the circumferential direction. Each recording unit has a prepit area in a non-groove portion of the substrate with a first prepit being represented as VFO information in the prepit area and a second prepit being represented as address information in the prepit area.

Abstract: In a memory control device for controlling the write-in/read-out operation for a memory of a recording/reproducing apparatus, a sector data storing area and an additive area are set in each sector-based data storing area in the memory. A prescribed data is stored in the additive area associated with the sector-based data stored in the sector data storing areas. The access addresses for the additive area are generated on the basis of the sector count value when the sector data write-in or read-out is carried out in the memory. The access addresses are calculated by the memory control device.

Abstract: A beam is irradiated to an information recording medium having land tracks and groove tracks alternately formed on a track formed in turn on an information recording surface thereof and pre-pits so pre-formatted as to deviate from the center of the track, a return beam of the irradiated beam is received by detectors split into two parts in a track direction to obtain a differential signal, the pre-pit is detected from this differential signal and control of recording and reproducing processings is executed by using the pre-pit detection signal so obtained as the reference.

Abstract: An optical recording/reproducing apparatus for recording/reproducing information on a medium including a light source, an optical system for focusing and irradiating a light beam generated by the light source on the medium, a photodetector for detecting a reflected beam from the medium, and a circuit for reproducing information by using a signal from the photodetector. The medium includes a substrate with grooves and lands alternately formed on the substrate in a radial direction. The grooves and the lands both serve as recording tracks with the recording tracks being divided into recording units in the circumferential direction. Each recording unit has a prepit area in a non-groove portion of the substrate with a first prepit being represented as VFO information in the prepit area and a second prepit being represented as address information in the prepit area.

Abstract: A method for recording audio data onto a compact disc so as to discourage unauthorized copying thereof, the method including sampling a source audio data stream to determine at least one source audio data portion thereof the a derivative function of a sequence of samples of the source audio data portion is substantially constant, modifying the source audio data stream by substituting the source audio data portion with a substitute audio data portion, recording the modified audio data stream into at least one frame of the compact disc the frame has a P-channel, and setting the value of the P-channel that corresponds to the substitute audio data portion to 1.

Abstract: A beam is irradiated to an information recording medium having land tracks and groove tracks alternately formed on a track formed in turn on an information recording surface thereof and pre-pits so pre-formatted as to deviate from the center of the track, a return beam of the irradiated beam is received by detectors split into two parts in a track direction to obtain a differential signal, the pre-pit is detected from this differential signal and control of recording and reproducing processings is executed by using the pre-pit detection signal so obtained as the reference.