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: 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: A data reproduction device in conformity to Viterbi decoding includes an inverted-selected path generation part for receiving a selected path and an inverted candidate, selecting and modifying the selected path corresponding to the inverted candidate so as to produce a inverted-selected path that is an inverted version of the selected path, and outputting a number of the inverted-selected paths in parallel, the number corresponding to a number of the inverted candidates selected for the selected path of a predetermined data length and a second candidate data generation part for generating second candidate data from the inverted candidate. The device further includes a data selection part for selecting between the first and the second candidate data based on error detecting results.

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 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 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: 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: 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: Acrylic fibers with high physical properties particularly suitable as material for cement reinforcement are provided by spinning a spinning solution of an acrylonitrile polymer at a particular linear velocity ratio of extrusion, thereby forming gel fibers; regulating the internal water content of the gel fibers, subjecting the fibers to dry-heat treatment under tension or dry-heat stretching under a particular temperature condition; and cooling the fibers under tension.