Abstract: According to one embodiment, a data reproducing device according to the invention includes a frequency difference detector, a phase comparator, a loop filter, an integrator, a first conversion part for converting a value of the integrator into a first conversion value, a second conversion part for converting the value of the integrator into a second conversion value, a first conversion table, a second conversion table, a first D/A converter (DAC), a second D/A converter (DAC), a voltage controlled oscillator (VCO), and a prediction table. The value of the integrator and the first conversion value are associated with each other and stored in the first conversion table in consideration of the characteristics of the VCO. Meanwhile, the value of the integrator and the second conversion value are associated with each other and stored in the second conversion table in consideration of the characteristics of the VCO.

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: According to one embodiment, a phase-locked loop circuit comprises a phase difference detection unit which detects a phase error between a reproduced binary data and extracted clock and generates phase error pulse signals each having an amplitude corresponding to the phase error, a phase sifter sensitivity adjusting unit which generates a first adjustment pulse signal produced by adjusting the phase error pulse signal, and a loop filter unit which generates a pulse train signal for feedback control to generate the extracted clock from the first adjustment signal, wherein the phase shifter sensitivity adjusting unit comprises a first pulse doubler unit which generates an expanded pulse signal which doubles a time width of the phase error pulse signal, and a first amplifying unit which amplifies the amplitude of the expanded pulse signal and generates the first adjustment pulse 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: An optical-disc recording/playback apparatus performs recording/playback to/from an optical-disc having a data area serving as a recordable area and a header area in which address information of the data area is pre-recorded by embossing. The apparatus includes an area determining unit for determining the data area and the header area based on a playback signal from the optical-disc, an AD converter for converting the playback signal from an analog signal to a digital signal, and a playback decoding unit for reading information of the data area and the header area from the digital signal output from the AD converter. During playback of the data area, the playback decoding unit performs first playback decoding processing. During playback of the header area, the playback decoding unit performs second playback decoding processing without making changes to a basic configuration of the playback decoding unit.

Abstract: An optical disc recording and reproducing apparatus includes a maximum likelihood detection unit for decoding binary data from a reproduced multivalued signal from an optical disc, an equalization error generation unit for obtaining an equalization error signal from an input signal and an output signal to and from the maximum likelihood detection unit, a convolution processing unit for performing a convolution operation between the equalization error signal and plural values determined by the partial response class, a pattern detection unit for detecting plural predetermined data sequence patterns from the binary data output from the maximum likelihood detection unit, and a grouping and averaging processing unit for calculating a recording compensation amount for each type of the data sequence patterns by grouping convolution output signals output from the convolution processing unit in accordance with the type of the data sequence patterns and by averaging each of the grouped convolution output signals.

Abstract: An optical disc recording and reproducing apparatus which reproduces data by the PRML scheme includes a recording waveform generating unit for generating a recording waveform, a reproducing unit for reproducing the recorded data to generate reproduction data, a defect determining unit for determining whether or not a defect is included in a reproduction signal, a reproduction state determining unit for determining whether or not the reproduction state is stable, and a recording learning unit for performing recording learning for determining a parameter of a recording waveform on the basis of the reproduction data. The recording learning unit performs the recording learning on the basis of the reproduction data acquired when the reproduction state is stable.

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: According to one embodiment, a data recording and reproducing apparatus includes: a reproduced signal output device reading data recorded on an optical recording medium to output a reproduced signal; and a waveform compensation amount data generating device generating waveform compensation amount data of a recording waveform corresponding to recording data which is to be recorded to the optical recording medium. At the time of recording learning, this data recording and reproducing apparatus integrates, for each pattern, waveform error data which are used as a basis of the generation of the waveform compensation amount data by the waveform compensation amount data generating device, and adjusts output of a pattern instruction signal for instructing which of the patterns is an integration target, so as to integrate, for each pattern, the waveform error data in a target test write area corresponding to an integer number of rotations of the optical recording medium.

Abstract: A sync pattern detection apparatus includes a sync pattern detection unit configured to detect a sync pattern from an input signal, a plurality of sync pattern protection units configured to protect the sync pattern detected by the sync pattern detection unit, a reliability evaluation unit configured to evaluate the reliabilities of a plurality of sync pattern protection situations by the plurality of sync pattern protection units, and a selection unit configured to select a sync pattern protected by a predetermined sync pattern protection unit, on the basis of the reliability evaluation of the plurality of sync pattern protection situations by the reliability evaluation unit.

Abstract: An apparatus for reproducing digital data recorded on a recording medium by a Partial Response Maximum Likelihood method, the digital data being recorded in a code pattern in which the same code continuously appears at least two times, includes an analog-to-digital converting unit that samples an analog reproduction signal recorded on the recording medium and converts the sampled analog reproduction signal into a digital signal; a sampling rate switching unit that adaptively switches the sampling rate in the analog-to-digital converting unit from a higher rate to a lower rate; and a data demodulating unit that reproduces and demodulates the digital signal subjected to the analog-to-digital conversion in the analog-to-digital converting unit by the Partial Response Maximum Likelihood method in accordance with the switching between the higher rate and the lower rate.

Abstract: There is provided a recording apparatus which modulates record data by a predetermined modulation method and records record patterns corresponding to the record data on an optical disk, including a random data generator which generates random data as the record data, a data exchange processor which performs exchange processing on the random data so as to equalize a frequency of appearance of each of the record patterns relative to the entire record patterns on the optical disk corresponding to the respective random data, a modulator which modulates the random data subjected to the exchange processing by the predetermined modulation method, an optical head which records record patterns corresponding to the modulated random data on the optical disk, and reproduces the modulated random data from the recorded record patterns, and a record learning unit which calculates correction amounts for recorded positions of the respective record patterns based on the reproduced random data.

Abstract: According to one embodiment, in an information recording and reproducing apparatus, a record data correction unit generates correction data for correcting a record waveform generated according to record data. Further, the information recording and reproducing apparatus generates discrimination data for use in pattern discrimination performed to generate the correction data, using decoded data outputted from a PRML signal processing unit and the record data, and outputs the generated discrimination data to the record data correction unit.

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, 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: 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, 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: 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: 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.