Abstract: An information system according to the invention comprises a record carrier (1) and a playback apparatus (20). The record carrier has information marks along a track (11) thereof and exhibits first variations caused by existence and nonexistence of the information marks along the track. The first variations represent an information signal recorded on said record carrier. The record carrier further exhibits second variations (W) caused by variations associated with the information marks. The phase of the second variations is coupled to the phase of the first variations.

Abstract: A device for demodulating position information that is recorded as track wobbling in a record medium by a BPSK scheme includes a carrier-wave-generation circuit which derives a carrier wave from a wobbling signal obtained from the record medium, a phase-adjustment circuit which generates a phase-comparison signal having a 90° phase difference relative to the carrier wave, a multiplier which multiplies the wobbling signal and the phase-comparison signal to supply a product signal, and a detection circuit which detects a phase error of the carrier wave introduced by the carrier-wave-generation circuit by detecting the phase error between the wobbling signal and the phase-comparison signal based on the product signal.

Abstract: Information reproduction apparatus of the present invention is directed to realize data reproduction properly and reliably from an optical disk, including a wobble detection circuit (130) to detect a wobble signal read out by an optical head (500), a PLL circuit (150) to frequency-multiply the wobble signal to generate a synchronizing signal (SS0), a delay circuit (170) delaying a synchronizing signal (SS0) sequentially to generate a plurality of synchronizing signals (SS0-SS10) of different phases, a particular pattern detection circuit (190) to detect a particular pattern in a reproduced signal, and a switching unit (210) to select one synchronizing signal having a phase difference preset by a preset circuit (180) with respect to a detected particular pattern and supplying the selected synchronizing signal to a laser drive circuit (230) and to a signal demodulation circuit (90).

Abstract: In an optical information reproduction device for reproducing information from an optical disk medium on which an identification information area including first identification information shifted radially outward with respect to the center of a recording track by a specified distance and second identification information shifted radially inward with respect to the center of a recording track by a specified distance, and a user information area disposed along the center of a recording track are disposed, information is reproduced using a sum signal and a difference signal of the outputs from a split photodetector having at least two light-receiving parts disposed on opposite sides of a track tangential line. The first or second identification information signal is inverted and the direct-current component in the identification information signal and the user information signal are removed.

Abstract: A data recording medium suitable for an optical disk such as DVD is disclosed. The data recording medium has a plurality of sectors. The sector comprises a header area to store address information of the sector, a gap area for power calibration of a laser beam used for data recording, a data recording area to store a plurality of modulated codes obtained by modulating the data, a postamble area located immediately after the data recording area, and a buffer area to separate sectors. The modulated code includes information to demodulate a modulated code located immediately before the each modulated code. The postamble area stores information to demodulate the final demodulated code in the data recording area. Data pattern stored in the postamble area includes synchronization pattern, is determined based on DSV of the data pattern, or satisfies the run length limitation.

Abstract: In an optical disk drive apparatus for recording data on and reproducing data from an optical disk using both of data recording tracks formed of grooves and lands, is divided into an integer number of sectors, and the address data area of each sector is shifted in the radial direction. When a first sector is scanned, a data from the address data area of the first sector is read as a first direct address data, and a data from the address data area of an adjacent sector is read as a second direct address data. A first modified address data of the first sector is produced by modifying the second direct address data with an inter-track address difference, and a correct address value of the first sector is produced using the first direct address data and the first modified address data.

Abstract: Provided are an optical information medium, an optical information recording method and an optical information recording apparatus in which an accurate cross talk can be predicted with a simple structure in a recording mode such as CLV so that a disk having a cross talk reduced can be created.

Abstract: A disk reproducing apparatus is provided which can cope with the intermittent access due to track jump in the conventional CD reproducing system and which can reproduce data at N times the normal speed and produce the reproduced data at the normal speed. The disk reproducing apparatus includes a memory for storing the data and time information reproduced from the disk to match with each other, another external memory, a detection circuit detecting the time difference between the finally produced output data and the data which is being accessed, and a control circuit detecting the overflow/underflow of the external memory and controlling it to be written. The construction can absorb the time difference between the system operation speed and data output speed even during an intermittent access so that continuous data can be produced.

Abstract: An information recording/reproducing apparatus includes first and second data demodulators having different data discriminating capabilities. The first data demodulator has a lower data discriminating capability and the second data demodulator has a higher data discriminating capability. When the reliability of reliability information for demodulation data generated by the first data demodulator, the second data demodulator is operated so that demodulation data generated by the first data demodulator is replaced by demodulation data generated by the second data demodulator during a period of time when the reliability of the reliability information is deteriorated.

Abstract: A disk of the present invention includes a first storage area for reproducing data and a second storage area for recording and reproducing data, the number of sectors in each track in the first and second storage areas close to each other is larger in the first storage area than in the second storage area, and leading edges of sectors in each track in the first storage area are aligned in at least one line in a radius direction.

Abstract: Disclosed is an optical disk barcode forming method wherein, as information to be barcoded, position information for piracy prevention, which is a form of ID, is coded as a barcode and is recorded by laser trimming on a reflective film in a PCA area of an optical disk. When playing back the thus manufactured optical disk on a reproduction apparatus, the barcode data can be played back using the same optical pickup.

Abstract: A data recording and reproducing method for an optical disk data storage system to record data compressed at different data compression rate according to an operator's specification, and to reproduce the recorded data by decompressing. According to the operator's indication, the data is recorded at certain data compression rate in indicated area. The information of the data compression rate and the recorded area is stored as a table of contents (TOC) data. The TOC data is reproduced and stored in a memory after the optical disk is loaded. The recorded data is reproduced by selecting a decoding circuit to decompress the data. The decoding circuit is selected by referring the TOC data to identify data compression rate of the recorded data. Also the TOC data is referred to identify read-in and read-out region of the recorded data. The position of a pick-up when the data recording is started and ended, is recorded as the TOC data to provide random access capability for the data reproduction.

Abstract: The present invention is aimed at providing an optical disk, an optical disk device, and an optical disk reproduction method, for allowing for stable and efficient reading of address information. The optical disk includes a plurality of tracks each divided into a plurality of recording sectors. Each of the recording sectors includes a header region. The header region includes address information for identifying the position of the corresponding recording sector and address synchronous information for identifying the recording position of the address information for bit synchronization. The address information has been modulated using a run length limit code of a maximum inversion interval of Tmax bits (Tmax is a natural number), and the address synchronous information includes two patterns of which inversion interval is (Tmax′+3) bits or more, so that the reproduced signal of the address synchronous information is distinguished from the reproduced signal of other information.

Abstract: The present invention is aimed at providing an optical disk, an optical disk device, and an optical disk reproduction method, for allowing for stable and efficient reading of address information. The optical disk includes a plurality of tracks each divided into a plurality of recording sectors. Each of the recording sectors includes a header region. The header region includes address information for identifying the position of the corresponding recording sector and address synchronous information for identifying the recording position of the address information for bit synchronization. The address information has been modulated using a run length limit code of a maximum inversion interval of Tmax bits (Tmax is a natural number), and the address synchronous information includes two patterns of which inversion interval is (Tmax+3) bits or more, so that the reproduced signal of the address synchronous information is distinguished from the reproduced signal of other information.

Abstract: The present invention is aimed at providing an optical disk, an optical disk device, and an optical disk reproduction method, for allowing for stable and efficient reading of address information. The optical disk includes a plurality of tracks each divided into a plurality of recording sectors. Each of the recording sectors includes a header region. The header region includes address information for identifying the position of the corresponding recording sector and address synchronous information for identifying the recording position of the address information for bit synchronization. The address information has been modulated using a run length limit code of a maximum inversion interval of Tmax bits (Tmax is a natural number), and the address synchronous information includes two patterns of which inversion interval is (Tmax+3) bits or more, so that the reproduced signal of the address synchronous information is distinguished from the reproduced signal of other information.

Abstract: The present invention is aimed at providing an optical disk, an optical disk device, and an optical disk reproduction method, for allowing for stable and efficient reading of address information. The optical disk includes a plurality of tracks each divided into a plurality of recording sectors. Each of the recording sectors includes a header region. The header region includes address information for identifying the position of the corresponding recording sector and address synchronous information for identifying the recording position of the address information for bit synchronization. The address information has been modulated using a run length limit code of a maximum inversion interval of Tmax bits (Tmax is a natural number), and the address synchronous information includes two patterns of which inversion interval is (Tmax′+3) bits or more, so that the reproduced signal of the address synchronous information is distinguished from the reproduced signal of other information.

Abstract: An optical disc has a plurality of tracks for recording information represented as marks and spaces between the marks. The marks are formed by an optical beam modulated by a plurality of drive pulses (202) where a number of the drive pulses is determined according to a length of a mark part in the original signal to be recorded to the track. The optical disc has a control information recording area (2504) for storing a first pulse position Tu value indicative of rising edge of the first drive pulse for determining a start position of a mark to be recorded, and a last pulse position Td value indicative of falling edge of the last drive pulse for determining an end position of a mark to be recorded.