Abstract: A CD subcode transfer system includes a means for receiving a CD signal and outputting, along with a subcode, digital data derived from the CD signal after the digital data is error corrected and demodulated. The CD subcode transfer system also includes a means for determining whether a CRC check bit for Q channel data of the subcode is correct and for determining whether the Q channel data is correct upon comparison of the Q channel data with preceding Q channel data. In addition, the CD subcode transfer system includes a means for transferring the subcode and attaching the subcode to the digital data when the CRC check bit is determined to be correct and the Q channel data is determined to be correct.

Abstract: The present invention provides an optical information reproducing method of detecting a record mark formed in an optical information recording medium and generating a reproduced signal, comprising the steps of: detecting a mark length of each record mark on basis of a reproduced signal, and correcting the reproduced signal by a correction amount corresponding to the detected mark length, and an optical information reproducing apparatus for detecting a record mark formed in an optical information recording medium and generating a reproduced signal, comprising: a detection circuit for detecting a mark length of each record mark on basis of a reproduced signal, and a correction circuit for correcting the reproduced signal by a correction amount corresponding to the detected mark length.

Abstract: An optical recording medium for accurately deriving the address information or the disc rotation control information despite narrow track pitch and for recording signals to a high density, and a method and apparatus for recording and/or reproducing such optical recording medium. The optical recording medium has a wobbled groove and pits formed at a pre-set interval in an area between turns of the wobbled groove. The recording/reproducing method includes controlling rotation of the optical recording medium by a wobbled signal from the groove and detecting the position on the optical recording medium of a recording signal by pit signals detected from the pits. The recording/reproducing apparatus includes a detection device for detecting the wobbled signal from the groove and a detection device for detecting pit signals from the pits.

Abstract: The present invention provides digital read channel circuitry for an optical disk reader. An RF signal corresponding to a track on the optical disk is sampled to provide digital samples corresponding to the RF signal. The samples are taken at a rate that may differ from the channel bit rate of the RF signal. The digital samples are then processed to provide data at the channel bit rate. Multiple digital read channels may be used to read multiple tracks of an optical disk simultaneously. The multiple RF signals may be sampled based on a sample clock common to the multiple digital read channels.

Abstract: In providing a system that can manage access to data to effectively prevent illegal access to the data or the like, there is provided a system for embedding access management information that prepares management information for managing access to the data, and embeds the management information in the data through data transformation without changing amount of data. In managing access to data, there is provided a method that extracts management information embedded in the data through data deformation without changing amount of data, and manages access to the data according to the extracted management information. There is also provided a method for changing management of access to the data according to the type of medium in which the data is stored (RAM or ROM).

Abstract: The present invention relates to an optical disk, an optical disk device, and an optical disk recording method. When it is applied to, for example, a compact disk. It attempts to reduce a jitter at the time of reproduction, and reproduce surely the recorded data. A change pattern of a modulation signal (S2) is detected, and the timing of a modulation signal (S1) is corrected according to this change pattern, to irradiate a laser beam L.

Abstract: A data reproduction apparatus for an optical disc system is provided. Included is an analog-to-digital converter (ADC) for sampling an input RF signal and outputting the sampled result, an adder for adding the sampled signal and an asymmetry correction signal. The added signal is output. A blank/defect detector is provided for generating a blank detection signal if no change in data is detected from the added signal during a predetermined interval of time. A correction signal generator is provided for calculating a digital sum value (DSV) from the received added signal, generating an asymmetry correction signal based on the calculated DSV, and outputting the generated asymmetry correction signal to the adder. A waveform equalizer is provided for waveform-equalizing the added signal. A decoder is provided for decoding the waveform-equalized signal and outputting the result.

Abstract: A frame number correction signal generating circuit generates a control signal for correcting a frame number counter in the unit of two frames based on an out-of-sync. signal output from an out-of-sync. detection circuit and the least significant bit of a frame number output from a frame number detection circuit. The frame number counter corrects the frame number in the unit of two frames according to a control signal supplied from the frame number correction signal generating circuit. Therefore, the continuity of two frames constituting one row of ECC block can be maintained and a lowering in the correction ability of the error correction circuit can be prevented.

Abstract: The demodulated signal from the optical disk, containing a plurality of addresses is supplied to the address decoder which sets error detection flags when address decoding fails. If all addresses fail to decode, an address interpolator performs address interpolation up to a stored maximum number of iterations, thereby allowing data to be continuously read out from the demodulated signal. The maximum number is stored in memory. If at least one address is decoded, the address interpolator selectively updates the stored maximum number to achieve higher performance in reproducing data items from the optical disk.