Abstract: A comparator includes a variable-gain amplifier circuit configured to vary an amplitude of an input signal by changing a gain in accordance with a control signal, and a comparison section configured to compare a slice level interlocked with a signal level received from the variable-gain amplifier circuit with an output signal received from the variable-gain amplifier circuit and generate an output signal in accordance with a comparison result.

Abstract: When writing on a recordable medium the recorder can encounter write errors. When a write error occurrs the record carrier is discarded. By ignoring write errors in sections of the record carrier comprising unused information, for instance sections of the lead-in or lead-out the record carrier no longer needs to be discarded.

Abstract: An optical disk drive includes a servo control unit 7 for causing an optical disk A to be driven; an optical pickup 2 for reading recorded data from the recording surface of the optical disk A after carrying out focus pulling-in of an object lens; a CPU 8 for controlling the servo control unit 7 and optical pickup 2 to perform readout operation of data recorded on the optical disk A; and a temperature detecting unit 9 for detecting temperature in the optical disk drive. The CPU 8 calculates the focus pull-in level in accordance with the temperature detected by the temperature detecting unit 9, and carries out the focus pulling-in of the optical pickup 2 using the focus pull-in level.

Abstract: In an optical disk apparatus having an exclusive RF detector plane mounted therefore, as a method of obtaining a synthesized readout signal based on band-synthesis is used in order to obtain a readout signal having a good S/N ratio, a waveform distortion easily caused by a delay time difference or a sensitivity difference in the playback at higher speeds can be prevented. In order to correct the delay time difference or a sensitivity error in two channels of RF signals to be band-synthesized according to the selection of the sensitivity or playback speed, a delay time controller, a sensitivity controller, and a selector for selecting a combination method are engaged. An information holder for such control or selection is also provided.

Abstract: A method for inspecting an optical information storage medium includes irradiating the medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.

Abstract: The present invention relates to a method for operating an optical drive system (12) capable of reproducing/recording information from/to an optical carrier (1), wherein the optical drive system includes a focus controller (PID) for controlling a focus actuator (4), and a focus memory loop (ML) for applying a stored correction signal to the focus actuator (4). The method aims at avoiding impacts between the focussing means (3) and the optical carrier (1), by gradually stopping the focus control loop in response to an event, such as a user initiated ejection of the optical carrier. The gradual stop of the focus control loop is achieved by gradually reducing a memory loop parameter of the focus memory loop (ML), and by gradually reducing a controller parameter of an integrating part (I) of the focus controller (PID). It is an advantage of the invention that the phase of the stored correction signal is synchronized with the angular position of optical carrier (1) during the gradual stopping.

Abstract: A method for inspecting an optical information storage medium includes irradiating the medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.

Abstract: A method for inspecting an optical information storage medium includes irradiating the medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.

Abstract: An optimum method for adjusting the physical position or angle of an optical pickup (a1) is automatically selected for each optical disc signal processing device so that a control target value after adjusted is included in a previous margin measurement result which is stored in a nonvolatile memory, thereby providing an optical disc signal processing device, an optical disc signal processing method, an optical disc reproduction and recording device, and an optical disc reproduction and recording method, which can reduce the start-up time and the recording start time, and enhance the user's convenience.

Abstract: A reproducing device includes a detection circuit and an integration circuit. The detection circuit detects a push-pull signal PP. The integration circuit carries out integration processing with respect to one or greater frames of the push-pull signal, and carries out binarization processing with respect to integration results thus obtained, thereby detecting sub data. In the integration circuit, the more the frames to be used for detecting sub data is, the higher the accuracy of the detected sub data is. The reproducing device further includes a control circuit for controlling the total number of the frames to be used for generating valid sub data in the integration circuit. The control circuit controls the total number of the frames in accordance with a result of an error correction made by an error correction circuit.

Abstract: To provide an optical disk recording/reproducing apparatus capable of immediately suspending recording if a recording inadequate state occurs after start of recording, confirming the recording state by using an error-correction-code word unit and restarting recording after identifying the write continuation position. A recording starting section (1) instructs a recording gate/recording data creating section (5) to create a recording gate corresponding to a desired volume of data and recording data and to perform recording. If an inadequate-recording-state determining section (2) detects a recording inadequate state, a recording suspending section (3) instructs the recording gate/recording data creating section (5) to suspend outputting the recording gate and the recording data. A SYNC detection section (9) detects a SYNC signal from reproduced data, and a PO-error-correction processing section (11) performs PI-error-correction.

Abstract: In an optical disk apparatus according to an exemplary embodiment of the invention, a management information retaining unit retains an information group which should regularly be recorded as disk management information. The disk management information is obtained from a disk loaded in the optical disk apparatus, and the obtained disk management information and the information group retained by the management information retaining unit are compared with each other to detect an error in the disk management information obtained from the disk. The detected error of the disk management information is corrected into regular information, and recording and reproducing operations are performed to the disk based on the corrected disk management information.

Abstract: According to one embodiment, a disk drive configured to write data to a disk being rotated by a spindle motor has a synchronous clock generator that generates a synchronous clock to use during the write operation. The synchronous clock generator inputs the rotational acceleration of the spindle motor, as feed-forward control value, to the feedback control system provided in the drive disk, thereby generating a clock that is synchronous with the rotational speed of the disk.

Abstract: Respective demodulated outputs from a plurality of branches 11a to 11d are fed to corresponding error correction units 13a to 13d and error-corrected. The error correction units 13a to 13d feed error signals to error determination units 14a to 14d. The error determination units 14a to 14d determine the error-incidence situations of the respective branches 11a to 11d and then output the determination results to a coefficient generation unit 15. Based on the results of determination by the error determination units 14a to 14d, the coefficient generation unit 15 obtains the synthesis coefficients for the respective branch outputs. The synthesis coefficients correspond to the error-incidence situations of the respective branch outputs and are appropriate values including no errors. By synthesizing the respective branch outputs by use of the synthesis coefficients, error-free data can be reproduced.

Abstract: A reproduction data recording method for an optical storage medium. The method comprises storing additional data to a first temporary region of a memory device; reading the first recorded data from the optical storage medium and storing the first recorded data to the first temporary region; reading a data segment of the second recorded data from the optical storage medium and storing the data segment to a second temporary region of the memory device; reading the first recorded data from the first temporary region and the data segment from the second temporary region, and decoding the first recorded data and the data segment to confirm accuracy of the first recorded data; reading the first recorded data and the additional data from the first temporary region, and encoding the first recorded data and the additional data to generate encoded data; and writing the encoded data to the optical storage medium.

Abstract: A read circuit of a disk drive system that adaptively reduces signal-dependent noise including a sequence detector, a signal-dependent adaptive engine and a signal-dependent post-processor. The sequence detector recovers a data sequence from equalized data. The signal-dependent adaptive engine generates signal-dependent coefficients, a mean value and a standard deviation of a signal-dependent error. The signal-dependent post-processor corrects the signal-dependent error.

Abstract: A waveform shaping portion receives a digital reproduced signal generated from an analog reproduced signal reproduced from an information recording medium and shapes the waveform of the digital reproduced signal. A maximum likelihood decoding portion applies maximum likelihood decoding to the digital reproduced signal in the shaped waveform and generates a binarized signal indicating the result of the maximum likelihood decoding. A phase detection portion extracts, during the maximum likelihood decoding/a phase error using state transition patterns having only a single zero cross point among differential metrics at a plurality of merging points at which a set of paths branched from a given state merges. A synchronization detection portion generates a reproduction clock signal using the phase error that has been detected and brings the digital reproduced signal into synchronization with the reproduction clock signal that has been generated.

Abstract: The present invention provides an optical information reproducing method of detecting a record mark formed in an optical information recording medium and generating a reproduced signal, comprising the steps of: detecting a mark length of each record mark on basis of a reproduced signal, and correcting the reproduced signal by a correction amount corresponding to the detected mark length, and an optical information reproducing apparatus for detecting a record mark formed in an optical information recording medium and generating a reproduced signal, comprising: a detection circuit for detecting a mark length of each record mark on basis of a reproduced signal, and a correction circuit for correcting the reproduced signal by a correction amount corresponding to the detected mark length.

Abstract: According to one embodiment, an optical disk apparatus is provided with a read section which reads data from an optical disk to output read information, a determination section which determines presence/absence of an error of the read information to output an error presence/absence signal, a transfer processing section which receives the error presence/absence signal and receives a hash request signal and transfers the hash request signal when the error presence/absence signal indicates the absence of an error, and does not transfer the hash request signal when the error presence/absence signal indicates the presence of an error, and a processing section which performs hash processing to the read information upon reception of the hash request signal.

Abstract: An information recording medium in which bottoms of a guide groove and a pit array formed on a disc substrate are allocated on a same flat plane and shaped in flat. Further, in a transition area from a pit array to a guide groove or from a guide groove to a pit array, the information recording medium is provided with an intermediate area composed of a pit array of which height changes from a height between a bottom and a side of a groove to another height between the bottom and a side of the pit array.

Abstract: A reproducing device includes: a laser light irradiating section; a correction coefficient information retaining section; a correction coefficient obtaining section; a laser power setting section; and a driving signal outputting section.

Abstract: A method for calibrating signal offsets on a lightscribe disc is provided. Spoke signals of an inner ring are utilized as a counter in order to read information pattern signals of an outer ring in a predetermined marked area. Measure the signal offsets of the information pattern signals. Check whether the number of the spoke signals of the inner ring exceeds a predetermined value. When the number of the spoke signals does not exceed the predetermined value, continue to measure the signal offsets; and when the number of the spoke signals reaches the predetermined value, calculate an average signal offset. The signal offsets of the information pattern signals of the outer ring can be calibrated by utilizing the average signal offset during a radial calibration or a decoding calibration.

Abstract: An optical disc apparatus includes: a rotation section to rotate an optical disc including a spiral or concentric track with a predetermined track center, with a rotational center of the optical disc as the center; a light source to emit a light beam; an objective lens to collect the light beam on the optical disc; a lens drive section to drive the objective lens in a tracking direction; a light-receiving section to receive a reflected light beam and generate a light-receiving signal; a tracking error signal generation section to generate a first tracking error signal based on the light-receiving signal; an eccentric-state acquisition section to acquire an eccentric state of the track center; a correction section to generate a corrected tracking error signal; and a drive control section to drive the objective lens in the tracking direction by the lens drive section based on the corrected tracking error signal.

Abstract: A waveform shaping portion receives a digital reproduced signal generated from an analog reproduced signal reproduced from an information recording medium and shapes the waveform of the digital reproduced signal. A maximum likelihood decoding portion applies maximum likelihood decoding to the digital reproduced signal in the shaped waveform and generates a binarized signal indicating the result of the maximum likelihood decoding. A phase detection portion extracts, during the maximum likelihood decoding, a phase error using state transition patterns having only a single zero cross point among differential metrics at a plurality of merging points at which a set of paths branched from a given state merges. A synchronization detection portion generates a reproduction clock signal using the phase error that has been detected and brings the digital reproduced signal into synchronization with the reproduction clock signal that has been generated.

Abstract: The invention concerns a method and a device for scanning data stored on a recording medium. The device comprises a reading head and further comprises: means to calculate an error rate of the data read by said reading head, said data being arranged as groups of data, means to align the reading head in respect with the next data to be read according to said error rate of the data read, the reading head reads at least twice some of said groups, changing position in respect with the group of data from one reading to the other, means to compare the calculated error rate corresponding to each position of the said reading head, means to align the reading head with the relative position in respect with the groups of data giving the lowest error rate in order to read the following groups of data, and the means to align the reading head adjust the frequency of the groups of data read at least twice.

Abstract: The present invention provides an optical information recording apparatus and method capable of effectively determining appropriate recording parameters in a short time with favorable efficiency, when recording information onto an optical disk having different information recording conditions and information recording characteristics. An information recording condition or an information recording characteristic of an optical disk 1 is identified, and a recording pulse position is corrected at a correction accuracy according to the identifies information recording condition or information recording characteristic, such that a recording mark is formed in a predetermined position.

Abstract: The invention provides a tracking control device, a tracking control method, and an optical disc apparatus that enable to stably perform the tracking control, and reduce an influence of stray light from the other layer on the tracking control. A sub push-pull signal correcting section corrects a sub push-pull signal to be generated from returning light of a sub beam in such a manner that a track crossing component of a main push-pull signal to be generated from returning light of a main beam, and a track crossing component of the sub push-pull signal to be generated from the returning light of the sub beam are canceled. A low pass filter reduces a high frequency component of the sub push-pull signal corrected by the sub push-pull signal correcting section. A subtractor subtracts a sub push-pull signal passing the low pass filter from the main push-pull signal to thereby generate a tracking error signal.

Abstract: An optical recording medium driving device includes an optical head, an evaluation signal generating section, a focus servo section, a spherical aberration correction section, a focus bias adjuster, and a system controller. The optical head has a focus servo mechanism and a spherical aberration correction mechanism, irradiates a laser light, and detects a reflected light. The evaluation signal generating section generates, based on the reflected light, an evaluation signal. The focus servo section drives the focus servo mechanism according to a focus error signal to perform focus servo. The spherical aberration correction section drives the spherical aberration correction mechanism to perform spherical aberration correction. The focus bias adjuster adds focus bias to a focus loop. The system controller performs an operation for setting an adjustment spherical aberration correction value.

Abstract: A CD-Audio System includes a CD-module and a host unit. The CD-module reads audio data from a disc, checks the audio data for errors, and provides the checked audio data to the host unit at greater than 1 times CD audio rate. The host unit stores the received audio data in an electronic shock protection memory included in the host unit. When the CD-module determines an error in the audio data, the CD-module notifies the host unit of the position in the audio data of the error and when notified of a position in the audio data of an error, the host unit replaces stored audio data at that position and all subsequently already received data with retransmitted audio data. Then the host outputs only validated audio data via speakers.

Abstract: The invention provides a reading method of an optical disc drive, which includes setting, reading, and decoding data, accumulating the error amount of the decoded data, setting to re-read the data when a reading failure occurs, adding one to the error amount, setting a low number of retry attempts for a high error amount and a high number of retry attempts for a low error amount based on the error amount, retrying to re-read the data if the number of retry attempts does not reach the predetermined number of retry attempts, and determining that the reading fails if the number of retry attempts reaches the predetermined number of retry attempts.

Abstract: A series of marks on an optical disc are sampled to yield a series of data pulses. The marks are at least substantially angularly equidistant to one another on the optical disc. A function is performed on the series of data pulses to yield an error-corrected series of data pulses. The function is one of: frequency domain filtering, signal averaging, and signal integration.

Abstract: The object of the present invention is to curtail the time required from the receipt of a demand for certification processing of a rewritable optical disk from an apparatus of the higher order to the receipt of a demand for recording processing. In order to achieve this object, a digital data recording method for recording on a rewritable optical disk includes certification processing including a first step of recording certification data for the certification processing on the optical disk, a second step of recording user data different from the certification data on the optical disk after the first step, and a third step of reproducing the data recorded in the first step or the second step after the second step, and switches the certification processing based on the result reproduced in the third step.

Abstract: In an optical information recording device and optical information recording method for angularly multiplexing and recording data on pages on the same recording region on a hologram disk, data on each page is sequentially generated by sequentially dividing input data in predetermined units, the pages to be recorded on the same recording region are divided into page groups so that pages to be recorded adjacently by the angular multiplexing may not belong to the same group, each page group is individually subjected to inter-page coding processing for computing an error-correcting code and adding the computed error-correcting code, and data on the pages subjected to the inter-page coding processing is angularly multiplexed and recorded on the hologram disk.

Abstract: An optical information recording/reproducing apparatus is adapted to record and/or reproduce multilevel information on/or from an optical information recording medium. The multilevel information is recorded in the form of pits in cells virtually formed at regular intervals on a track. The respective levels are represented by varying the length or the area of information pits such that a reproduced signal has a different amplitude level depending on the length or the area of information pits. A reproduced signal correction circuit corrects a reproduced signal obtained by performing sampling at the center of each cell. An error power calculation circuit calculates error power on the basis of the difference between the corrected reproduced signal and an ideal value of each level of the cell. A decoder performs decoding on the basis of the calculated error power values.

Abstract: The present invention discloses a method for dynamically detecting writing quality of a recordable optical disc. According to the method, firstly a current detecting position located on a program area of the recordable optical disc is set. Then the recordable disc drive proceeds data recording in the program area with an optimal write power. The recordable disc drive paused data recording when a recording position exceeds or is equal to the current detecting position. Then the recordable disc drive reproduces pre-recorded data in the tracks of the recordable optical disc to perform OPC for modifying the optimal write power and calculating a jitter value. Thereafter a following detecting position is modified based on the jitter value and data recording is restarted in the program area with the modified optimal write power until the recording position exceeds or is equal to the modified following detecting position.

Abstract: When user data fails to be recorded in an address of a user data area, the same data is recorded in an address of a spare area. Information indicating that the data for the address of the user data area is recorded in the address of the spare area is registered in a DL that is loaded in a buffer memory, and the information is recorded in a currently-valid DL area of DMA1. As similar thereto, the information is recorded in a currently-valid DL area of DMA2. If the recording fails, the DL is alternatively recorded in another DL area of the same DMA2. Thereafter, DDSs of DMA2 are deleted, and then, without changing information of the number of times of updating the DDSs, only the staring address of the DL of the DDSs is updated. According to the updating method, it is possible to shorten the time required for updating management information of a medium in an information recording/reproducing apparatus.

Abstract: A data processing apparatus for outputting a plurality of picture data forming reproduced data to a reproduction apparatus for reproduction, the data processing apparatus having a processing circuit for judging if the reproduction rate of the picture data by the reproduction apparatus is slower than a transfer rate for transferring the picture data to the reproduction apparatus and outputting all of the picture data forming the reproduced data to the reproduction apparatus when judging as a result of the judgment that the reproduction rate is slower than the transfer rate.

Abstract: Embodiments of the invention control a recovery procedure effectively in accordance with write conditions. In one embodiment, the data to be written into a sector includes not only user data but also recording condition data, which indicates the temperature prevalent during a write. If a data read is not accurately performed, a recovery procedure is executed. If a data read is accomplished by a retry and the temperature prevalent during a write is lower than predetermined, it is concluded that the employed medium is nondefective. Thus, the read data is rewritten into the same sector without being stored in a spare area. This prevents the spare area from being unnecessarily consumed.

Abstract: A recording and/or reproducing method, a recording and/or reproducing apparatus, and a computer readable recording medium storing a program for performing the method. A recording unit block in which invalid data is partially padded is written on an information storage medium along with padding information indicating that the invalid data is included in the recording unit block. The padding information is useful in determining whether the recording unit block includes the padding data. Accordingly, unnecessary retrial processes of a drive system are reduced such that the performance of the drive system is improved and error correction capability is enhanced.

Abstract: This optical disk device includes a pickup head, a spindle motor, a signal generation unit, a runout amount calculation unit, and an out of balance disk detection unit. The signal generation unit generates a tracking error signal. The runout amount calculation unit controls the rotational speed of the spindle motor to first and second disk rotational speeds, and obtains, at these rotational speeds, runout amounts TE1 and TE2 of a tracking error signal, and runout amounts FE1 and FE2 of a focus error signal. And an out of balance disk detection unit detects that this optical disk is an out of balance disk, if the absolute value of (TE2×FE2)/(TE1×FE1) is greater than or equal to a threshold value.

Abstract: A disk drive apparatus includes: head means for performing laser irradiation to and detection of reflected light from an optical disk recording medium and having a focus bias mechanism and a spherical aberration correction mechanism; focus bias means for driving the focus bias mechanism to add a focus bias to a focus servo loop; spherical aberration correction means for driving the spherical aberration correction mechanism based on a spherical aberration correction value; evaluation value creating means for creating an evaluation value based on reflected light information obtained by the head means; adjustment means for adjusting the focus bias and the spherical aberration correction value; and control means for determining whether data is written on at least one track of the tracks adjacent to an adjustment use range on the recording medium and controlling an adjustment operation on the focus bias and the spherical aberration correction value by the adjustment means based on the determination result.

Abstract: A method for correcting write strategy data of an optical disc may include setting initial values, measuring and storing the width of a generated write enable signal, and calculating an offset correction value. The initial values may include a data write rate, a number of write strategy data, a maximum number of steps of a time parameter to be applied to the write strategy data, step sizes of the steps in the time parameter, and a generated modulated signal. A write enable signal may be generated whenever the time parameter is varied by a step size, and a width thereof may be measured and stored. The offset correction may be determined by calculating an offset correction value corresponding to a difference between the stored width of the write enable signal and a predetermined value of the write enable signal.

Abstract: A disk recording medium which can implement a recording method having a high degree of reliability for additional information is disclosed. The disk recording medium has a recording and reproduction region into and from which first data can be recorded and reproduced in accordance with a rewritable or write-once-read-many recording method and from which second data recorded in the form of wobbling of a groove can be reproduced. The second data includes address information and additional information. The additional information of the second data is coded in accordance with a first error correction method, and the coded additional information and the address information are recorded in a state coded in accordance with a second error correction method.

Abstract: A technique to detect defects when reading a defect scan pattern stored on a disk in which the detected defects are processed differently depending on which region of a sector the defect is resident. In one implementation, a mask is used to identify the defects of different regions. By differentiating different regions within the sector for defect scan, sync mark and preamble fields may be treated as critical regions so that different defect scan properties may be attributed when performing the defect scan.

Abstract: A write-once optical recording medium, a method for allocating a defect management area of the write-once optical recording medium, and a method for allocating a spare area of the write-once optical recording medium are provided. A method of managing defects on a write-once optical recording medium having at least one recording layer includes the steps of allocating at least one temporary defect management area having a fixed size and at least one temporary defect management area having a variable size to said optical recording medium, respectively, recording defect management information on the at least one temporary defect management area having a fixed size and the at least one temporary defect management area having a variable size; and using the at least one temporary defect management area having a fixed size and the at least one temporary defect management area having a variable size is provided herein.

Abstract: An apparatus includes a first circuit and a second circuit. The first circuit may be configured to generate status signals and an error signal in response to accessing a storage medium. The error signal provides a first value based on an accuracy of accessing the storage medium. The second circuit may be configured to offset the first value of the error signal to a second value to increase the accuracy of accessing said storage medium. The status signals include one or more of a data signal and a differential signal. In a first mode, an offset signal is generated in response to the data signal. In a second mode, the offset signal is generated in response to the differential signal.

Abstract: A DPD tracking error signal detection apparatus includes the following. Four differentiators remove DC components and differentiate four signal with varying differential phases. The signals are then sampled and quantized by four A/D converters, and output to a non-inverting unit and an inverting unit. A phase inverter/compositor then leaves as-is or phase-inverts the output signals, according to a control signal. The non-inverting and the inverting unit each include two Hilbert transformers that phase-shift the output from the A/D converters, two delay units that delay the output of the other A/D converters to match the delay of the Hilbert transformers, two cross-correlators that calculate the cross-correlation between pairs of Hilbert transformers and delay units, and an adding unit that combines the cross-correlator results and outputs the combined result to the phase inverter/compositor.

Abstract: An information reproducing apparatus (1) is provided with: a judging device (20) for judging whether or not a read signal (RRF) read from a recording medium (100) satisfies a desired reproduction property; a correcting device (18) for correcting waveform distortion occurring in a read signal corresponding to a long mark, of the read signal if it is judged that the read signal does not satisfy the desired reproduction property; and a waveform equalizing device (15) for performing a waveform equalization process on the read signal in which the waveform distortion is corrected.

Abstract: An optical disk drive includes a servo control unit 7 for causing an optical disk A to be driven; an optical pickup 2 for reading recorded data from the recording surface of the optical disk A after carrying out focus pulling-in of an object lens; a CPU 8 for controlling the servo control unit 7 and optical pickup 2 to perform readout operation of data recorded on the optical disk A; and a temperature detecting unit 9 for detecting temperature in the optical disk drive. The CPU 8 calculates the focus pull-in level in accordance with the temperature detected by the temperature detecting unit 9, and carries out the focus pulling-in of the optical pickup 2 using the focus pull-in level.

Abstract: An optical disc drive for recording and playing back a recordable-type optical disc includes a driving mechanism for rotating the optical disc, an optical pick-up for writing and reading data to and from the optical disc, signal processor for processing signals read out from the optical disc by means of the optical pick-up, a CPU for controlling the driving mechanism, the optical pick-up and the signal processor. The optical disc drive is further equipped with a detecting device for detecting an ATIP error and a counter for counting the number of ATIP errors. The optical disc drive counts the number of ATIP errors caused in a predetermined time based on the synchronization signal (SUBCODE-SYNC) produced by a clock provided in the optical disc drive after the synchronization signal (SUBCODE-SYNC) has been synchronized with a synchronization signal (ATIP-SYNC) obtained from a reference optical disc.