Kabushiki Kaisha Toshiba

Koichi Otake

Toshihiko Kaneshige

Yukiyasu Tatsuzawa

Hiroyuki Moro

Hideyuki Yamakawa

Tadashi Kojima

Yoshiyuki Ishizawa

A disk device includes a reading section which reads reflected light and outputs a read signal according to the read reflected light, a processing section which calculates an adjustment value from the read signal, performs predetermined processing on the read signal based on the adjustment value, and outputs a process signal, a detecting section which detects a reading defect in the reading section based on the read signal, a determining section which determines signal quality of the process signal output from the processing section, a storage section which stores the adjustment value calculated by the processing section, in a memory area, based on a result output from the determining section, and a controller which, when the detecting section detects the reading defect, performs control so that the adjustment value is read out of the storage section and is supplied to the processing section.

Disk device and disk reproduction method that prevents a wrong reproducing operation when a defect on the disk is determined

A recorded stream generator generates a data block stream in synchronism with the phase of a recording clock, from the input data. The recorded stream generator further generates, for each predetermined data unit constituting the data block stream, a data phase reference pulse indicative of the phase of the data unit. An inserting section inserts a VFO signal into a predetermined amount (32 sectors) of the data block stream, the VFO signal having a length of time corresponding to a difference in phase between an wobble address phase signal and a data phase reference pulse. The inserting section thus provides a data stream DST consisting of the VFO signals and the data block streams. An LD uses light beams to record the data stream on an optical disk.

Optical disk apparatus, method of recording information, and information recording medium

A disk apparatus has an equalizing unit which performs PR equalization for the read signal from the disk based on a plurality of tap coefficients, a decoding unit which performs a decoding process for the equalized read signal, a calculating unit which obtains an ideal signal of the decoded read signal, and compares the ideal signal with the decoded read signal, thereby calculating an error signal E, and a control unit which groups the tap coefficients into at least a first and second coefficient groups which are groups of tap coefficients at symmetrical locations each, and determines tap coefficients of the first coefficient group in a range of a first limit value Kaccording to the calculated error signal, determines tap coefficients of the second coefficient group in a range of a second limit value and supplies the determined tap coefficients to the equalizing unit.

Disk apparatus and method using plural tap coefficient equalization

A sync pattern detection apparatus includes a sync pattern detection unit configured to detect a sync pattern from an input signal, a plurality of sync pattern protection units configured to protect the sync pattern detected by the sync pattern detection unit, a reliability evaluation unit configured to evaluate the reliabilities of a plurality of sync pattern protection situations by the plurality of sync pattern protection units, and a selection unit configured to select a sync pattern protected by a predetermined sync pattern protection unit, on the basis of the reliability evaluation of the plurality of sync pattern protection situations by the reliability evaluation unit.

Sync pattern detection method and apparatus

When an error-correcting code is created for the data stored in a memory and added to the data, even if an error occurs in the data on the memory, the adverse effect of the error will be eliminated. In the present invention, when the data is stored in the memory, an error-correcting code PI is created beforehand using another memory, such as an S-RAM. The error-correcting code PI, together with the data, is written into the memory. After 16 sectors of data and PI have been stored, an error-correcting code PO is created for the data and PI and added to them. When the data is read from the memory, a PI correcting process is carried out each time a PI series is read out. This makes it possible to restore the original data, even if the data is destroyed (or an error occurs) on the memory.

Data processing method using error-correcting code and an apparatus using the same method

A disk apparatus has a reading unit which reads reflection light from a disk and outputting a read signal, an identifying unit which identifies whether the read signal has been modified in accordance with a first modulation rule or has been modulated in accordance with a second modulation rule and outputs an identification signal, an equalizing unit which applies a waveform equalizing process to the read signal, and a decoding unit which carries out likelihood decoding of the waveform equalized read signal according to the modulation rule indicated by the identification signal from the identifying unit, and outputs a reproduction signal.

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Yokohama, Japan

Koichi Otake