Hitachi, Ltd.

Hitachi Video Engineering, Incorporated

Takuya Mizokami

Atsushi Saito

Shinichi Arai

Takeshi Maeda

Takehiko Sekine

Naozane Yoshida

Naoto Matsunami

Eisaku Saiki

Satoshi Kawamura

Kikuo Shimizu

Kazuo Isaka

Hiroshi Suzuki

Kazuo Shigematsu

Masahiro Takasago

Hisataka Sugiyama

Toshimitsu Kaku

Toru Kawashima

Masanori Matsuzaki

Osami Kushizaki

Noritaka Narita

Fumiaki Ikeda

Akira Takagishi

Toshiharu Kon

Histaka Sugiyama

A reproducing apparatus including a reading apparatus for reading signals recorded on a recording medium, a reproducing apparatus for reproducing data from read-out signals from the reading apparatus, an error detector for detecting an error in the data reproduced by the reproducing apparatus, a phase-synchronizing apparatus for synchronizing signals, for the reproducing apparatus, a characteristic changing apparatus for changing reproduction characteristics of the reproducing apparatus of loop characteristics of the phase-synchronizing apparatus, when the error detector detects an error on any one of a track on the recording medium, and a retry apparatus for retrying reading of a track on which the error is detected, under changed reproduction characteristics.

Reading/reproducing apparatus having retry arrangement upon failed reading/writing of a signal

An information recording/reproducing method is disclosed for an information recording/reproducing apparatus including a recording medium having a disk-like shape, a unit for rotating the recording medium at a constant angular velocity, a unit for recording code information so that the bit length of the code information becomes approximately constant with respect to a radial position on the recording medium, a unit for modulating the code information to be recorded to form a modulated signal, and a recording unit for forming in the recording medium a localized recording region having a different physical property with respect to an unrecorded region, the recording unit being controlled by the modulated signal so that the code information is recorded to correspond to the edge of the recording region, wherein the bit rate of the code information to be recorded changes depending on a location on the recording medium, and a part of each of a recording characteristic of the apparatus and a reproducing characteristic of the apparatus is changed in accordance with a location on the recording medium.

Optical recording method employing pit edge recording on recording

If information is to be recorded on and reproduced from a recording medium in correspondence between a code train in the form of a run-length-limited code and the positions of the leading edge and the trailing edge data of a status transition pattern such as pits, recording domains, a sync signal is inserted at regular intervals in the information converted in the form of the run-length-limited code. The sync signal is constituted by a code train capable of deciding that the sync signal includes a code not existing in the conversion rule into a run-length-limited code during reproduction using a leading edge data or trailing edge data relative to the transition pattern.

Data recording/reproducing device

In recording and/or reproducing data into and from a disk record medium having a record medium in which a plurality of tracks are arranged radially, the record area is divided into a plurality of zones, and a clock frequency is assigned to each zone. The data recording and/or reproducing are performed according to the clock of the frequency assigned to the respective zone. Each zone is subdivided to include a plurality of tracks, and a clock having a different frequency is assigned to each zone. Each frequency is set in such a manner that the record capacity of the track gradually becomes larger as the zone is nearer to the outer zone.

Disk record medium, and method and apparatus for recording and

Information recording/reproducing device and method in which a

A recording and reproducing apparatus is provided with a recording circuit to record information on a recording medium rotated and a reproducing circuit to reproduce the information from the recording medium rotated. In the mode of reproducing the information from the recording medium, the reproducing circuit retries reproduction if any error has occurred to the data reproduced. The reproducing circuit is provided with a characteristic changing circuit to change its reproduction characteristic. In the mode of reproducing information from the recording medium, the reproducing characteristic of the reproducing circuit is changed by the characteristic changing circuit if any error has occurred to the reproduced data. The reproducing circuit uses the changed reproducing characteristic to retry the reproduction.

Recording and reproducing apparatus having arrangement for recovery of

A PLL circuit produces a synchronous signal by utilizing a regenerative clock signal in a VFO portion in a regenerative signal which was read out from a recording medium in sections. When a defective portion is present in a regenerative clock signal, the same sector is read out again from the recording medium to obtain the regenerative signal. A loop gain of the PLL circuit is made to be low in the defective portion of the regenerative signal which was read out again, thereby to prevent the synchronous fault of the PLL circuit due to the defective portion.

Apparatus for reproducing data from a regenerative signal using a PLH

Optical information recording/reproducing apparatus using pit edge

Recording and reproducing apparatus including changing a reproduction

Information recording/reproducing device and method for

A recording/reproducing apparatus detecting a starting position of each data recording block or sector on a data recording medium, such as an optical disk. A VFO pattern and a CRC code are recorded at a starting position of each of the sectors. The VFO pattern and the CRC code are utilized for detecting a starting position of each sector with no predetermined pattern or sector mark, on the recording medium, which is dedicated for the starting position detection. This improves data formatting efficiency of the recording medium while maintaining the accuracies of automatic focusing and tracking even in a system employing pit-edge recording/reproducing.

Reproducing apparatus reproducing data from a recording medium having a

An optical information memory apparatus in which after a coarse seeking operation to position an optical head to a position near a seeking target address at a high speed has been executed, only at a time point when a light spot has reached a predetermined region from the center of a track near a seeking target address, the pull-in control of the light spot to the track center is executed. The optical information memory apparatus has: a zero-cross pulse generator for receiving a tracking error signal and for producing tracking error zero-cross pulses; and a window comparator for receiving the tracking error signal and for producing tracking error window pulses which are obtained by slicing the tracking error signal by predetermined binary slice levels of an upper limit and a lower limit. Further, at a time point when a period of time of the low level of the tracking error zero-cross pulse is equal to or larger than a predetermined time interval T.sub.0 and the tracking error window pulse has been set to the low level, the tracking control to pull the light spot into the track near the desired seeking target address is executed.

Track servo pull-in method and apparatus for an optical disc

A method for detecting a starting position of each data recording block or sector on a data recording medium, such as an optical disk. A VFO pattern and a CRC code are recorded at a starting position of each of the sectors. The VFO pattern and the CRC code are utilized for detecting a starting position of each sector with no predetermined pattern or sector mark, on the recording medium, which is dedicated for the starting position detection. This improves data formatting efficiency of the recording medium while maintaining the accuracies of automatic focusing and tracking even in a system employing pit-edge recording/reproducing.

Method for detecting starting position of data recording block

In a method for recording/reproducing information, a reference pattern is recorded in a certain predetermined domain so that the leading-edge and the tailing-edge of a certain recorded portion are positioned in a predetermined relationship, when coded bits of data are recorded on a recording medium by forming recorded portions physically different from not recorded portions, while making them correspond to leading-edges and tailing-edges of the recorded portions. A first and a second reproduced signal indicating the leading-edge and the tailing-edge of the recorded portion, respectively, are detected independently from each other from a reproduced waveform corresponding to the recorded portion, which has been thus recorded; and the first and the second reproduced signal are reconstructed while correcting edge shifts produced at recording data by storing the first and second reproduced signal in a memory, so that the first and the second reproduced signal indicate the leading-edge and the tailing-edge of the recorded portion corresponding to the reference pattern, respectively, in the predetermined relationship.

Method for recording/reproducing information having a function of

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Odawara, Japan

Takuya Mizokami