Abstract: The present invention comprises generating sections which generate intermediate information for error correction processing in units of surfaces from an error correction block stored in a first storage section, the error correction block having A/B surfaces, second storage sections which store intermediate information, a processing section which generates correction information that carries out error correction processing in several units divided within units of surfaces for the error correction block stored in the first storage section on the basis of the intermediate information, and control sections which correlate position information of the error correction block with position information in units of surfaces for use in the generating sections, the second storage sections, and the processing section.

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 data processing apparatus may include a memory unit which stores information including sync frame data, a preceding calculation system circuit which makes a syndrome calculation from the information including sync frame data, a retry calculation system circuit which makes a syndrome calculation from information stored in the memory unit, a buffer group which stores a calculation result of the preceding calculation system circuit or that of the retry calculation system circuit, and a correction execution process system circuit which executes error correction for the information including sync frame data according to the calculation result stored in the buffer group.

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 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 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: 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 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.

Abstract: A disk apparatus has a reading portion which reads out a plurality of frames stored in a disk and outputs a read signal, a detecting portion which determines that part of the read signal is identical to a frame synchronization code signal or determines that a deviation between a symbol of part of the read signal and a symbol of the frame synchronization code signal is within a certain time range to detect the frame synchronization code signals from the read signal, and a reproducing portion which reproduces the read signal in synchronization with the detected frame synchronization code signals.

Abstract: A data processing apparatus according an aspect of this invention has a syndrome calculation unit configured to calculate the syndrome of a demodulated data sequence. The syndrome calculation unit includes a calculation unit configured to make the calculation required to realize syndrome calculation of demodulated data for each frame obtained by removing the sync code from one sync frame.