Abstract: An optical disk device which decodes data recorded on an optical disk, comprises a first measuring unit which measure a cycle of a plurality of first synchronous signal regions VFO contained in a reproduction signal from an optical pickup, a cycle comparing unit which compares the measurement result of the first measuring unit with a first predetermined cycle, a second measuring unit which measures a cycle of a plurality of second synchronous signal regions SYNC which are contained in the reproduction signal from the optical pickup and have the cycle shorter than that of the plurality of first synchronous signal regions VFO, a cycle comparing unit which compares the measurement result of the second measuring unit with a second predetermined cycle, and an oscillator which generates a clock signal CKS for sampling the reproduction signal on the basis of the comparison results of the first and second cycle comparing units.

Abstract: According to one embodiment, there is provided an optical disk apparatus including a detecting unit which reads a reflective light from an optical disk and outputs a read signal, a decoder which decodes the read signal from the detecting unit, an extracting unit which extracts from the read signal the first and second specification information of the same content recorded in first and second areas on the optical disk, a processor which compares the first specification information with the second specification information and processes the specification information based on the comparison result, and a controller which controls the detecting unit or the decoder, based on the specification information processed by the processor.

Abstract: An information reproducing apparatus according to the present invention is capable of reproducing an information storage medium storing BCA information recorded in a first area and RF information recorded in a second area on an outer side of the first area. The information reproducing apparatus includes an optical pickup to radiate laser light onto the first and second areas and detect reflected light thereof; a reproducing system unit to reproduce an RF signal and a BCA signal on the basis of the reflected light; and a focus control unit to control focusing by setting a focus position to a signal layer of the optical disc when the RF signal is to be reproduced and control defocusing by displacing the focus position from the signal layer when the BCA signal is to be reproduced, thereby equivalently suppressing a high-frequency component of the BCA signal.

Abstract: According to one embodiment, a frequency detector detects a frequency error between a frequency of a reproduction signal supplied from an analog to digital converter and a frequency of a clock for conversion. A loop filter controls an oscillation frequency of a voltage control oscillator based on the frequency error and a phase error detected by a phase comparator. An adaptive equalizer equalizes a waveform of the reproduction signal supplied from the analog to digital converter to obtain a response of a predetermined PR class. A Viterbi decoder decodes the waveform equalized signal into binary data by maximum likelihood sequence estimation. A clock supply control circuit stops supply of a clock to at least the phase comparator, the adaptive equalizer and the Viterbi decoder in a case where the frequency error is larger than a designated error.

Abstract: A subject for the invention is to provide an unshaped refractory composition having not only high thermal resistance but also improved corrosion resistance and improved unsusceptibility to slag infiltration. The invention is “an unshaped refractory composition comprising: (1) 20 to 70% by weight raw spinel material comprising an MgO—Al2O3 spinel phase and containing 2 to 20% by weight magnesia and/or raw spinel/corundum material comprising an MgO—Al2O3 spinel phase and a corundum phase and containing 2 to 20% by weight magnesia; (2) 3 to 12% by weight raw magnesia material having a particle diameter of 0.3 mm or smaller, containing particle sizes of 75 ?m or smaller in an amount of 55 to 85% by weight, and having a magnesia purity of 90% by weight or higher; (3) 3 to 10% by weight alumina cement having a calcia content lower than 20% by weight; (4) 0.3 to 1.5% by weight ultrafine powder consisting mainly of silica; and (5) a raw alumina material as the remainder”.

Abstract: A plurality of defect management areas (DMA set groups 1 to N) are used in a ring form in such a manner that defect management information of the DMA replaces and is recorded in the next spare area while the DMA is supposed to be still sufficiently rewritable (e.g., currently used DMA sets #1-1 to #4-1 are replaced with the next DMA sets #1-2 to #4-2), and a process returns to a first defect management area again at a time when transition of the defect management information ends up to a last spare area (DMA sets #1-N to #4-N).

Abstract: According to this invention, an information recording medium has the first and second sides. The information recording medium includes the first information recording layer which includes the first reflecting layer reflecting incident light with a predetermined intensity from the first side, the second information recording layer which includes a second reflecting layer reflecting incident light with a predetermined intensity from the second side, an adhesion layer which adheres the first information recording layer and the second information recording layer, and a unique information recording area which is formed by burst-cutting the first reflecting layer and the second reflecting layer in correspondence with medium unique information, using incident light with an intensity higher than the predetermined intensity from one of the first side and the second side.

Abstract: A pre-learning section pre-learns whether or not a signal characteristic has been changed by use of at least data in a plurality of data areas, and obtains an optimum equalization coefficient of an adaptive equalizer for the data areas after the signal characteristic has been changed, and then stores the optimum equalization coefficient in a optimum equalization coefficient storage section. On the basis of detection information from a reference information (VFO) area detection section, the optimum equalization coefficient pre-learned in a reference information (VFO) area is preset in the adaptive equalizer, and equalization coefficient learning processing for the adaptive equalizer is started after entering a next data area.

Abstract: A signal processing circuit on a stage previous to a maximum likelihood decoder is more stably automatically controlled to have an optimum characteristic. A pre-equalizer, an offset control unit, an asymmetry control unit, an amplitude control unit, an analog digital converter, an adaptive equalizer, and a maximum likelihood decoder are sequentially arranged. A frequency control device and a phase control device are arranged. A sequencer feeds back error information obtained by the maximum likelihood decoder to any two of the offset control unit, the asymmetry control unit, the amplitude control unit, the analog digital converter, and the adaptive equalizer when at least the frequency control and phase control are set in predetermined control ranges, respectively.

Abstract: There is provided an apparatus which can flexibly cope with both of a signal reproduction process for a region with high recording density and a signal reproduction process for a region with low recording density. The apparatus includes a waveform equalizing circuit which subjects data read out from an optical disk to a waveform equalizing process, a plurality of PRML processors of different classes supplied with an output signal of the waveform equalizing circuit, a switch which selects one of output signals of the plurality of PRML processors and supplies the selected output signal to a decoder, and a controller which controls the switch according to high-density and low-density regions with different recording densities of the optical disk to set a selection state in which a corresponding one of the output signals of the plurality of PRML processors is selected.

Abstract: 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.

Abstract: A subject for the invention is to provide an unshaped refractory composition having not only high thermal resistance but also improved corrosion resistance and improved unsusceptibility to slag infiltration. The invention is “an unshaped refractory composition comprising: (1) 20 to 70% by weight raw spinel material comprising an MgO—Al2O3 spinel phase and containing 2 to 20% by weight magnesia and/or raw spinel/corundum material comprising an MgO—Al2O3 spinel phase and a corundum phase and containing 2 to 20% by weight magnesia; (2) 3 to 12% by weight raw magnesia material having a particle diameter of 0.3 mm or smaller, containing particle sizes of 75 ?m or smaller in an amount of 55 to 85% by weight, and having a magnesia purity of 90% by weight or higher; (3) 3 to 10% by weight alumina cement having a calcia content lower than 20% by weight; (4) 0.3 to 1.5% by weight ultrafine powder consisting mainly of silica; and (5) a raw alumina material as the remainder”.

Abstract: Error correction codes are generated by the respective components of an ECC block, then the codes are added so as to generate an error correction code of the ECC block as a whole. Because error correction codes have linearity, the same results can be obtained by adding the error correction codes after they are calculated separately, as the error correction code calculated as a whole ECC block. The error correction code is calculated by separating the ECC block, thereby the number of times to read/write from/to a memory can be restricted as a whole ECC block, and the amount of data to write/read to/from a memory can be reduced.

Abstract: A digital RF signal resulting from A/D conversion of an RF signal reproduced from an optical disk is compared with a plurality of set values, so that a predetermined waveform is detected from the digital RF signal. The wavelength of the detected waveform is measured, and the A/D conversion is controlled based on this wavelength. Comparing the digital RF signal with the plural set values enables high-accuracy waveform detection.

Abstract: 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.

Abstract: 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 K1 according 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.

Abstract: 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.

Abstract: An optical disk drive apparatus is provided has a reading section which reads the reflection of a laser beam from a disk to produce a read signal, a filter section which filters the read signal with the use of three or more different cutoff frequencies upon receiving a control signal from a two or more bits control line, a reproducing section which playbacks the read signal filtered by the filter, and a control section which provides the filter with the control signal along the two or more bits control line so that the filtering action with the three or more different cutoff frequencies of the filter is carried out throughout three or more consecutive periods respectively.

Abstract: An information storage medium has a system lead-in area and a data lead-in area, and an area identifying circuit identifies whether a light beam irradiation area of an optical pickup head is at the system lead-in area or at the data lead-in area based on a reproduction signal provided from the optical pickup head. The area identifying circuit identifies the respective areas by using the number of zero crossings obtained from a signal, for example, into which the reproduction signal is binarized. An information reproducing circuit reproduces information from the reproduction signal based on the identified result by the area identifying circuit.

Abstract: 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.