Abstract: A hologram recording/reproducing device for recording and reproducing information to/from a hologram recording medium adapted to multiplexing and recording of a plurality of page data. The medium includes an address region and a recording region, the medium including a plurality of physical addresses each composed of a first physical address and a second physical address. The recording/reproducing device includes: a recording part; and a reproducing part, the recording part specifying the plurality of physical addresses to write user data into a specific physical address, the recording part writing the second physical address together with the user data in a specific recording unit region specified by the second physical address, the reproducing part reading page data recorded in a designated physical address.

Abstract: In a data recording apparatus, values of parity bits to be additionally provided every one predetermined length block in data obtained by demodulating the original data are determined so as to satisfy a part of or an entire the predetermined run length limitation rule in ranges of a current predetermined length block, the plurality of parity bits, and a next predetermined length block that is positioned next to the current block. The parity bits having the values are additionally provided to the current block.

Abstract: In a data recording apparatus, values of parity bits to be additionally provided every one predetermined length block in data obtained by demodulating the original data are determined so as to satisfy a part of or an entire the predetermined run length limitation rule in ranges of a current predetermined length block, the plurality of parity bits, and a next predetermined length block that is positioned next to the current block. The parity bits having the values are additionally provided to the current block.

Abstract: Crosstalk cancellation is realized more accurately than ever by considering both magnitude and a phase difference of a crosstalk signal from a recording track adjoining a target track, in comparison with magnitude and a phase of a desired signal from the target track, which is implemented by providing a crosstalk amount detection means, a phase difference measurement means, and a crosstalk component generation means that generates a crosstalk component to be subtracted from a signal obtained by an optical scanning that includes the desired signal and the crosstalk.

Abstract: An apparatus for reproducing data includes a branch metric computation unit and a plurality of parallel computation units, each of which includes path metric computation units configured to compute path metric values based on branch metric values, path metric memories operable to store the path metric values to be used in a next following path metric computation, reliability computation units configured to compute path reliability, and modified-path generating units configured to generate an inverted path that is inverse to a path indicated by an output of the reliability computation units as having low reliability, wherein if any one of the modified-path generating units generates the inverted path, a corresponding one of the path metric computation units stores a path metric value corresponding to the inverted path in a corresponding one of the path metric memories as a path metric value to be used in a next following path metric computation.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: A data recording and reproducing system is provided that adds a first error correcting code to input data to generate a first code block, encodes the first code block with a second error correcting code to generate a second code block, interleaves the second code block to generate a recording block, and records and reproduces the recording block via a partial response channel including a recording medium. This system includes an iterative decoder that iteratively decodes an output signal from the partial response channel, and thus decodes the second code block; a preliminary decision and reliability detection unit that preliminarily determines decoded data and determines reliability of the decoded data, based on likelihood information obtained in the middle of iterative decoding in the iterative decoder; and a first error correcting code decoder that decodes the first error correcting code.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: In an apparatus for reading recorded data, the apparatus, a read signal is sampled from recorded data of a recording medium by synchronizing with a first clock signal. A sample value obtained by the sampling part is stored and also the sample value from the first storing part is retrieved by synchronizing a second clock signal different from the first clock signal and maximum likelihood data is detected by processing the sample value in accordance with a predetermined algorithm. The recorded data is read based on the detected data.

Abstract: An optical disk recording method of recording data on an optical disk by applying laser light to a track of the optical disk, includes the steps of a) driving a plurality of laser light sources in sequence in a time division manner, and applying a light flux to one track of the optical disk successively, and b) producing a plurality of rows of record marks in the one track.

Abstract: An optical disk recording method of recording data on an optical disk by applying laser light to a track of the optical disk, includes the steps of a) driving a plurality of laser light sources in sequence in a time division manner, and applying a light flux to one track of the optical disk successively, and b) producing a plurality of rows of record marks in the one track.

Abstract: According to the present invention, a data reproduction apparatus sampling, at a given rate, a reproduced signal obtained from a recording medium and complying with a partial response waveform, and reproducing data from sampled values of the reproduced signal in accordance with the Viterbi decoding algorithm includes difference value calculation means for calculating a difference between compared ones of path metric values in selecting paths, alternative path selection means for selecting a path different from a corresponding one of the paths, which are selected in accordance with a given rule, as an alternative path based on the difference between the compared ones of the path metric values, and reproduced data determination means for determining data to be reproduced based on the paths selected in accordance with the given rule and the alternative path.

Abstract: A magneto-optical recording medium, a method for recording and reproducing data using the medium and a magneto-optical recording apparatus are provided in which an optical head reads the recorded data while applying a magnetic field, and the ill effect of the leakage magnetic field from the neighboring tracks can be suppressed so as to obtain a correctly read signal. The magneto-optical recording medium includes a recording layer, an intermediate layer and a reproduction layer. The signal recorded in the recording layer is read using a light beam irradiated externally and a magnetic field applied externally. The signal recorded in the recording layer is transferred to the reproduction layer via the intermediate layer. Marks are recorded so that each of leading and trailing edges of a recorded mark is substantially aligned with center portions of a recorded mark or a space of neighboring tracks, and the neighboring tracks have different polarities.

Abstract: In an apparatus for reproducing recorded data, a crosstalk signal is generated by converting adjacent data recorded on an adjacent track into a waveform of said reproduction signal and the crostalk signal is deducted from the reproduction signal. Then, the reproduction signal in which the crosstalk signal is eliminated is decoded in accordance with the predetermined algorithm and reproduced.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: In an apparatus for recording and regenerating data, a pass metric is calculated based on a likelihood converted from a previous calculation result iteratively until all pass metrics of the same data recorded many times on a recording medium are calculated, and then data recorded on the recording medium is decoded.

Abstract: An optical disk recording method of recording data on an optical disk by applying laser light to a track of the optical disk, includes the steps of a) driving a plurality of laser light sources in sequence in a time division manner, and applying a light flux to one track of the optical disk successively, and b) producing a plurality of rows of record marks in the one track.

Abstract: The present invention provides a data recording device that can restrain the low-pass component in data to be written onto a recording medium without causing a problem in decoding the data using likelihood information. This data recording device includes: a data bit string combining unit that combines, by predetermined combining rules, a plurality of predetermined parity bit strings one by one with a data bit string obtained prior to a change to the bit order in a bit order rearranging procedure, thereby generating a plurality of composite data bit strings; and a data bit string selecting unit that selects one encoded data bit string from a plurality of encoded data bit strings generated through encoding procedures including the bit order rearranging procedure carried out for each of the plurality of composite data bit strings. Based on the selected encoded data bit string, the data recording device performs a data write operation onto the recording medium.