Showing papers by "Akiyoshi Uchida published in 2004"

Optical disk recording method, optical disk reproducing method, optical recording medium using the method, and optical disk drive

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.

Development of Signal Interpolated Phase Timing Recovery System for High Density Magneto-Optical Disks

Abstract: We developed a new timing recovery system for magneto-optical disks (MO) with a higher recording density and higher transfer rate but it is difficult to achieve these without signal to noise ratio (SNR) degradation in the MO readout signal Therefore, for signal processing, we have developed a turbo code technology, [rf1] which can obtain a high enough coding gain However, as optimal phase to obtain the optimum performance of the turbo code must be detected, we developed a very precise phase timing recovery system that works under a degraded SNR in the MO readout signal Moreover, as the turbo code is a kind of block code, which requires decoding by a turbo block unit, we also developed a system for detecting the start point for turbo decoding We developed a new timing recovery system and, in this paper, we report architecture and performance evaluations of this system

Data recording/reproducing system and method

Abstract: It is possible to provide a data recording/reproducing system capable of decoding the original data with a high accuracy when an error has occurred in the reproduced data In order to achieve this object, in the data recording/reproducing system, input data is added by a first error correction code to generate a first code block, the first code block is added by a second error correction code to generate a second code block, and the second code block is interleaved to generate a record block, so that recording and reproduction are performed via a partial response channel containing a recording medium The system includes a repeated demodulation unit for repeatedly demodulating an output signal of the partial response channel so as to demodulate the second code block, a temporary decision/reliability detection unit for temporarily deciding the decoded data from the likelihood information of the mid flow of the repeated decoding in the repeated decoding unit and deciding reliability of the decoded data which has been decided temporarily, and a first error correction code decoding unit for decoding the first error correction code The temporary decision/reliability detection unit supplies the decoded data which has been decided temporarily and the reliability information on the decoded data to the first error correction code decoding unit

Magneto-optical storage medium capable of recording plural rows of marks on each 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.