Abstract: It is an object of the present invention to realize a data recording disk that is resistant against burst errors and capable of quick access without sacrificing recording capacity. A disk 1 is divided into zones, and the number of sectors per track is made larger by one in a more outside zone than in a more inside zone. The disk 1 is driven at a constant rotational angular velocity. The sector is composed of an address area and a data area, and it is arranged for the address recorded in the address area to complete error detection and correction processing within the address area. An error detection and correction code in the data area is completed extending over a plurality of sectors.

Abstract: In an optical recording medium on which the main information is recorded on a pre-formed recording track along the track direction and in which the recorded data are read out by optical means, frame sync signals based on the same format as the format for the main information are pre-recorded by offsetting the recording track itself along its width for each frame as an information recording unit, for facilitating frame synchronization and simplifying the construction through the use of a sole common synchronizing circuit. The information pre-recorded by offsetting the track itself along its width includes not only the frame sync signals but also any reproduce-only information for increasing the disc recording capacity.

Abstract: An optical disc, an apparatus and a method for recording/reproducing the optical disc use Gray coded address information. The hexadecimal data 0 to F correspond to the Gray codes. The Gray code consists of the upper address and the lower address. The four channels of the upper address and the four channels of the lower address are set so that one channel of each address is "1". With the change of the data from 0 to F, the channel of "1" in the lower address sequentially moves to the adjacent channel in the corresponding Gray code. Consequently, rapid seeking can be performed by detecting only the lower address.

Abstract: An optical disc, an apparatus and a method for recording/reproducing the optical disk use Gray coded address information. The hexadecimal data 0 to F correspond to the Gray codes. The Gray code consists of the upper address and the lower address. The four channels of the upper address and the four channels of the lower address are set so that one channel of each address is "1". With the change of the data from 0 to F, the channel of "1", in the lower address sequentially moves to the adjacent channel in the corresponding Gray code. Consequently, rapid seeking can be performed by detecting only the lower address.

Abstract: A data recording apparatus for recording digital data to a data recording medium is disclosed, that comprises an error correction code encoding means for interleaving a predetermined unit of data to be recorded and encoding the resultant data with an error correction code, and an identifying means for identifying whether the data to be recorded is reproduction-only data or rewritable data, wherein said error correction code encoding means is adapted for changing the interleave length corresponding to the output of said identifying means.

Abstract: An optical disc having address information recorded in a wobbling manner is arranged to record or reproduce data at correct positions. A track is previously formed as a pregroove and is wobbled in accordance with address information. The track is divided into a plurality of sectors. A plurality of sync marks S are formed in each sector, and at least one of the sync marks in one round of the track is formed as a reference mark R different from the other sync marks S. To reduce overhead and to achieve highdensity random recording and reproduction, a method may also be used in which one cluster of data is formed of a data area and a link area located between data areas and consisting of two frames, in which each of the data area and the link area has a structure formed of unit frames separated by a sync signal (frame sync), and in which data is recorded or reproduced as unit clusters.

Abstract: An optical disc having address information recorded in a wobbling manner is arranged to record or reproduce data at correct positions. The optical disc includes at least one track on which data is recorded and which is previously formed as a pregroove wobbled in accordance with an address information, where the track has a plurality of frames wobbled in accordance with the address information, and further where a plurality of sync marks is formed in each of said frames by wobbling said pregroove at a center frequency of frequencies of wobbling with the address information.

Abstract: First error-processing data are generated with respect to a predetermined amount of data, and second error-processing data are generated with respect to each of a plurality of blocks produced by dividing the predetermined amount of data. Data of record units are generated from the predetermined amount of data, the first error-processing data, and the second error-processing data. The data of record units are recorded on and reproduced from a recording medium. Errors are corrected in the predetermined amount of data in the reproduced data of record units with the first error-processing data with respect to each of the record units. If errors cannot be corrected, at least errors are detected in the predetermined amount of data in each of the blocks with the second error-processing data.

Abstract: An optical dick, an apparatus and a method for recording/reproducing the optical disk use Gray coded address information. The hexadecimal data 0 to F correspond to the Gray codes. The Gray code consists of the upper address and the lower address. The four channels of the upper address and the four channels of the lower address are set so that one channel of each address is "1". With the change of the data from 0 to F, the channel of "1" in the lower address sequentially moves to the adjacent channel in the corresponding Gray code. Consequently, rapid seeking can be performed by detecting only the lower address.

Abstract: An optical disc having address information recorded in a wobbling manner is arranged to record or reproduce data at correct positions. The optical disc includes at least one track on which data is recorded and which is previously formed as a pregroove wobbled in accordance with an address information, where the track has a plurality of frames wobbled in accordance with the address information, and further where a plurality of sync marks is formed in each of said frames by wobbling said pregroove at a center frequency of frequencies of wobbling with the address information.

Abstract: An optical disc having address information recorded in a wobbling manner is arranged to record or reproduce data at correct positions. A track is previously formed as a pregroove and is wobbled in accordance with address information. The track is divided into a plurality of sectors. A plurality of sync marks S are formed in each sector, and at least one of the sync marks in one round of the track is formed as a reference mark R different from the other sync marks S. To reduce overhead and to achieve high-density random recording and reproduction, a method may also be used in which one cluster of data is formed of a data area and a link area located between data areas and consisting of two frames, in which each of the data area and the link area has a structure formed of unit frames separated by a sync signal (frame sync), and in which data is recorded or reproduced as unit clusters.

Abstract: A data recording apparatus is constructed by: an input unit for receiving first and second digital data in which a ratio of sector sizes is not equal to an integer ratio; a block segmenting unit for inserting first data nA and second data mB (n and m are integers of 2 or more and n.noteq.m) when it is assumed that a sector size of first data is set to A and a sector size of second data is set to B and for forming data of a block structure; a recording processing unit for performing an error correction encoding and a digital modulation to the data of the block structure; and a recording unit for recording the recording data from the recording processing unit to a data recording medium.

Abstract: A data recording region of a disc is divided into a plurality of zones, the plurality of zones comprising a plurality of bands, and with a range from an innermost radius to an outermost radius being divided into four bands by four radii, with the rotational velocity of the disc at each of the bands being fixed in such a manner as to increase disc capacity.

Abstract: An optical disk, an apparatus and a method for recording/reproducing the optical disk use Gray coded address information. The hexadecimal data 0 to F correspond to the Gray codes. The Gray code consists of the upper address and the lower address. The four channels of the upper address and the four channels of the lower address are set so that one channel of each address is "1". With the change of the data from 0 to F, the channel of "1" in the lower address sequentially moves to the adjacent channel in the corresponding Gray code. Consequently, rapid seeking can be performed by detecting only the lower address.

Abstract: It is an object of the present invention to realize a data recording disk that is resistant against burst errors and capable of quick access without sacrificing recording capacity. A disk 1 is divided into zones, and the number of sectors per track is made larger by one in a more outside zone than in a more inside zone. The disk 1 is driven at a constant rotational angular velocity. The sector is composed of an address area and a data area, and it is arranged for the address recorded in the address area to complete error detection and correction processing within the address area. An error detection and correction code in the data area is completed extending over a plurality of sectors.

Abstract: A magneto-optical recording and/or reproducing apparatus having a magnetic head and first and second optical systems for recording on and/or reproducing from first and second magneto-optical media. The first optical system has a first objective lens, and the second optical system has a second objective lens whose numerical aperture differs from that of the first objective lens. The magnetic head is arranged near the second objective lens. The first and second optical systems are arranged such that the respective one of the first and second magneto-optical media which is currently being subject to recording or reproducing is positioned between the first and second optical systems.

Abstract: A method of recording data on a disc on a disc pre-recorded with servo control data, with the servo control data being pre-recorded in the form of convex and concave pits at intervals along substantially concentric tracks, the servo control data recorded in alignment in a diametrical direction of the disc. The method includes the steps of dividing the disc into a plurality of zones in the radial direction, dividing the tracks into a plurality segments such that there is an equal number of segments in each interval between adjacent pre-recorded servo control data. The method further includes the step of recording reference data on at least one segment of the plurality of segments in each interval between adjacent servo control data, with the reference data being utilized to adjust a gain and a phase of a read-out clock upon reproduction of the disc.

Abstract: Error-correcting apparatus and method for detecting and correcting a burst error affecting a plurality of reproduced signals representing adjacent data words groups the signals, calculates syndromes, determines the positions of errors in the reproduced signals and detects burst errors.

Abstract: When data is recorded on a recording medium such as an optical disk and reproduced, if burst error occurs, the processing can be carried out efficiently and satisfactory reproduction can be carried out without lessening a data recording capacity. When data is recorded, a first error-correcting code is generated with respect to a series of data of a predetermined amount. The first error-correcting code is added to data of the predetermined amount from which the first error-correcting code is generated. A second error-correcting code is generated with respect to a series of data of the predetermined amount. The second error-correcting code is added to data other than data of the predetermined amount from which the second error-correcting code is generated and then recorded on a recording medium. Upon reproduction, data of a certain recording unit is reproduced from a recording medium on which data of respective recording units are recorded.

Abstract: A system of recording/reproducing data on and from a spiral or concentric track formed on a magneto-optical disc, in which a data recording area of the track is divided into a predetermined number of blocks. A reference data recording area is provided at a predetermined position of each of the blocks, in which continuous several bit data each of a high or low level is recorded, and, upon reproducing, a reproduced radio frequency signal is clamped at a signal level serving as a clamping level which is obtained by reproducing the data on the reference data recording area.