Abstract: When ld0 denotes an initial optical path length that is a length of an optical path, along which the signal light travels, as converted using a refractive index in vacuum, lm0 denotes an initial optical path length that is a length of an optical path, along which the reference light travels, as converted using a refractive index in vacuum, ?l denotes a fluctuation width of a difference in optical path lengths between the signal light and the reference light as converted using a refractive index in vacuum, ?0 denotes a central oscillation wavelength of the wavelength-variable laser, and ?? denotes an oscillation wavelength variable range of the wavelength-variable laser, then an initial optical path difference |ld0?lm0| satisfies |ld0?lm0|>(?l/??)?0.

Abstract: An optical drive device includes first and second light sources, an objective lens configured to receive a first light emitted from the first light source and a second light emitted from the second light source and to irradiate both the first light and the second light to an optical disc recording medium, a first focus mechanism configured to drive the objective lens in a focus direction, a second focus mechanism configured to change collimation of the second light incident to the objective lens and changing the focusing position of the second light independently of the first light, a first focus servo control unit configured to drive the first focus mechanism, an error signal subtraction unit configured to subtract the first focus error signal from a second focus error signal, and a second focus servo control unit configured to drive the second focus mechanism.

Abstract: An optical disk playback device comprises first and second lasers, an optical assembly, first and second optical detectors, and controller circuitry coupled to the optical detectors. The optical assembly is configured to direct incident light from the first and second lasers so as to form respective leading and trailing scanning spots on a surface of an optical disk, and is further configured to direct corresponding reflected light from the leading and trailing scanning spots on the surface of the optical disk to respective ones of the optical detectors. The controller circuitry is configured to identify a surface imperfection of the optical disk by processing the reflected light associated with the leading scanning spot prior to the trailing scanning spot reaching that surface imperfection.

Abstract: In one embodiment the present invention includes a qualification circuit that controls a read channel in a data storage device. The qualification circuit includes a first circuit and a second circuit. The first circuit receives a first signal and generates a second signal based on a signal quality of the first signal. The second circuit receives the second signal, an envelope-derived error signal resulting from performing envelope derived error detection, and a decision-aided error signal resulting from performing decision aided error detection. The second circuit modifies the envelope-derived error signal and the decision aided error signal according to the second signal. The second circuit generates a control signal that controls the read channel according to the envelope-derived error signal and the decision-aided error signal having been modified.

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: An optical pickup device includes an astigmatism element which imparts astigmatism to laser light reflected on a disc, a spectral element which changes propagating directions of four light fluxes obtained by dividing a light flux of the laser light reflected on the disc to disperse the four light fluxes from each other, and a photodetector having a sensor group which receives the four light fluxes. The optical pickup device is further provided with a memory which holds a correction value for suppressing a DC component in a tracking error signal resulting from a positional displacement of the spectral element. The tracking error signal is corrected by the correction value to thereby suppress the DC component.

Abstract: Provided is an objective lens including a diffraction portion provided on a laser beam incident plane or output plane. The diffraction portion includes first second, and third diffraction regions, wherein first laser beams corresponding to a first optical disc having a first transmissive layer are condensed on a data recording portion of the first optical disc, second laser beams corresponding to a second optical disc having a second transmissive layer thicker than the first transmissive layer are condensed on a data recording portion of the second optical disc, and third laser beams corresponding to a third optical disc having a third transmissive layer thicker than the second transmissive layer are condensed on a data recording portion of the third optical disc. An evaluation parameter calculated on the basis of an in-plane efficiency distribution function has a value corresponding to a symbol error rate that is less than a predetermined value.

Abstract: A data recovery device including a filter, a tilt detection unit, a tilt cancellation unit and a data conversion unit is provided. The filter filters a radio-frequency data stream to generate an original data stream. The tilt detection unit synthesizes a tangential push-pull data stream by employing a first to a fourth data streams, and generates a tilt direction signal according to symmetry of a curve composed by the tangential push-pull data stream. The tilt cancellation unit detects a plurality of rising areas and falling areas of the original data stream, and reconstructs a plurality of data points corresponding to the rising areas or falling areas in the original data stream so as to generate a tilt repair data stream. The data conversion unit recovers the tilt repair data stream to a modulation signal.

Abstract: A phase error detection device detects a phase error, based on an output from an A/D conversion section that performs A/D conversion on an analog input signal in accordance with a sampling clock to generate a digital reproduction signal. The phase error detection device includes a phase error generation section that generates the phase error from the output from the A/D conversion section, and a phase error correction section that corrects the phase error. Herein, the phase error correction section determines a phase error detection range from past phase errors and, when the phase error generated by the phase error generation section is out of the phase error detection range, corrects the phase error.

Abstract: An optical disk apparatus according to the present invention includes: a sub-data forming section for forming, from data to be recorded into an optical disk (3), element data (42a, 42b) constituting the data and parity data (42c) for reconstructing the data in a case where the element data (42a, 42b) becomes unreadable; and a recording position determining section for determining respective recording positions for the element data (42a, 42b) and the parity data (42c). The recording position determining section determines the respective recording positions for the element data (42a, 42b) and the parity data (42c) such that they do not overlap each other in a projection plane of the optical disk viewed in a light-irradiation direction. The arrangement makes it possible to improve reliability of data reconstruction in a case where data loss occurs in data recorded in the optical disk (3) in which data is recordable in a plurality of layers.

Abstract: A method for inspecting an optical information storage medium includes the steps of: irradiating the storage 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 that include a first linear velocity Lv1 and a second linear velocity Lv2 higher than the first linear velocity Lv1; 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 that irradiates the medium 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 for the focus and/or tracking error signal(s) to obtain residual errors

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: An audio/video information recording/reproducing device capable of easily implementing a post-recording function on an optical disk by using even a low-cost disk drive having a comparatively low-speed seek time. When recording a video file, it is recorded on an optical disk continuously for a duration equivalent to more than three times a seek time. When recording dubbing audio, it is recorded continuously only with constant data size at the same time with the reproducing of the recorded video file, thereby enabling concurrent real-time continuous reproducing and recording. Accordingly, concurrent reproductions of a video file and an audio file are ensured when reproducing dubbing audio.

Abstract: Aspects of the disclosure provide an apparatus. The apparatus includes a pick-up unit, such as an optical pick-up unit, a wobble channel and a defect detector. The pick-up unit generates a push-pull signal corresponding to a wobbled track of a storage medium. The wobble channel includes circuits to receive the push-pull signal, obtain a wobble signal from the push-pull signal, and calculate a wobble amplitude metric based on the wobble signal. The defect detector compares the wobble amplitude metric to a threshold to detect wobble defects.

Abstract: An optical disk apparatus includes an optical pickup and a signal processor. The optical pickup includes an actuator for driving an objective lens, and a detected light intensity signal output part for outputting a detected light intensity signal to the processor. The signal processor includes a servo signal generator for generating a main push-pull signal and a sub push-pull signal on the basis of the detected light intensity signal supplied from the detected light intensity signal output part, a signal generator for generating a differential push-pull signal and a lens error signal by conducting addition/subtraction on the main push-pull signal and the sub push-pull signal, and a tracking offset correction signal generator which is input with the lens error signal to output a tracking offset correction signal. The differential push-pull signal correction is conducted by conducting addition/subtraction between the differential push-pull signal and the tracking offset correction signal.

Abstract: Detecting a defect on a storage device is disclosed. Detecting includes receiving a signal read from a storage device, sampling the signal to obtain a set of signal samples, wherein the sampling starts at an arbitrary time, computing a defect value for a defect type using the set of signal samples, comparing the defect value with a threshold associated with the defect type, determining whether there is a defect of the defect type based at least in part on the comparison, and in the event that a defect is detected, outputting an indication associated with the defect.

Abstract: A semiconductor integrated circuit is equipped with a reproduction ECC circuit, a recording ECC circuit, a host interface circuit, and a memory control circuit. The memory control circuit includes an arbitration circuit and a count circuit. The arbitration circuit arbitrates ECC access with a priority order higher than the access of a host interface with a host apparatus. The count circuit counts the number of output times of the ECC request, and, when the count reaches a prescribed number, the count circuit generates a count termination signal. The arbitration circuit performs switching of priority orders to arbitrate the host with a priority order higher than that of ECC. The prescribed number corresponds to number of output times of the ECC access request necessary for accessing a semiconductor memory in relation to data of one ECC block or of an integral multiple of the one ECC block.

Abstract: [Object] A recoding playback apparatus and an optical disk are provided that allows reduction of a low frequency noise at a time of playback of a super resolution optical disk including small record marks whose size is below the diffractive limitation, to enhance quality of a playback signal. [Means for Solution] The reflective beams from the optical disk are received by dividing into outer portion beams and a center portion beam, and a playback signal is created by combining such beams based on respective different gains. Based on received amounts of light or amounts of low frequency noise in respective light receiving regions, adjustment or determination of gain values is made, or the optical head apparatus is optically adjusted, whereby the low frequency noise is optimally suppressed. Further, a specific region is provided on the optical disk for making the foregoing adjustment.

Abstract: According to the present invention, of all beams of light reflected from the optical disc, only light in a peripheral region excluding a push-pull region is used to generate a DPD signal. In this method of signal generation that optimizes internal light-receiving surface interconnections in a photodetector, the lens error signal required for the generation of a tracking error signal in the DPP scheme is amplified at a lower amplification factor. In addition, the light reflected from the multilayered optical disc will be divided into a plurality of regions and the divided beam of light will be focused at different positions on the photodetector. When the beam is focused upon a desired layer, stray light from recording layers other than those to be subjected to information reproduction will not enter the photodetector light-receiving surfaces used for servo signals.

Abstract: An optical article for playback in a player, the optical article including at least one sector having data, and a mark disposed in a predetermined relationship with the at least one sector, wherein the mark renders a portion of the data generally unreadable. The optical article further includes error correction code associated with the at least one sector, wherein data within the error correction code is configured as partially corrupted. The inclusion of partially corrupted error correction code reduces the size of the mark or spot required to render the data sector uncorrectable.

Abstract: A technique capable of realizing a power saving in a device for reproducing/recording digital signals by properly controlling a frequency of a clock. The device for reproducing/recording digital signals (device for reproducing an optical disk) includes: a difference comparing circuit for comparing a first parameter (demodulating block counter) updated each time a process for one correcting block is done in a demodulating circuit with a second parameter (error correcting block counter) updated each time a process of one correcting block is done in an error correcting circuit; and a circuit (clock controlling circuit etc.) for switching a frequency of a master clock (MCLK) depending on a comparison result of the difference comparing circuit. Thereby, the frequency of the clock can be switched both of when the demodulation for one correcting block is ended and when the correcting process for one correcting block is ended by using the switched master clock.

Abstract: Proposed is an optical disk device capable of appropriately performing focus control. In an optical disk device, an objective lens is moved in the thickness direction of an optical disk by controlling an actuator and a time interval in which each of the recording layers was detected is measured while moving the objective lens, a first time interval from the first detection of the recording layer to the second detection of the recording layer is compared with a second time interval from the second detection of the recording layer to the third detection of the recording layer, and a focal position of the objective lens is determined based on the comparative result.

Abstract: The present techniques provide methods and systems for more reliable reading of optical data disks. In embodiments, a multi-pixel detector that is segmented into multiple areas, or detector segments, may be used to detect a pattern in the light reflected from an optical data disk. The pattern may include light scattered from a single bit that may be under a center detector, as well as light scattered from proximate bits. The detector system may then combine the quantized values from each of the detector segments mathematically to determine the presence or absence of a bit or bits of data. The mathematical combination may also use data that is known about the status of adjacent data bits (such as previously read bits, or bit patterns which are allowed or not allowed by specific data encoding schemes) to improve the accuracy of the bit prediction.

Abstract: A device and method for reducing power consumption of an optical drive are proposed. The present invention samples a carrier control signal and then compares the samples of the signals with predetermined threshold signals. According to the comparison result, the present invention produces at least one diphase excitation control signal. The diphase excitation control signal comprises at least one impulse signal, and a negative edge of the impulse signal is adjusted to a predetermined level during the period of the diphase excitation control signal. The present invention reduces the time for outputting the control signals and greatly reduces the power consumption of the optical drive thereby.

Abstract: An optical disc reader comprising a controller that controls a read operation to read data recorded on an optical disc and a counter that counts the number of zero crossings in a tracking error signal. Between the completion of focusing operation and the start of tracking operation, the controller determines whether or not the light beam is properly focused on a data recording layer in the optical disc based on the number of zero crossings in the tracking error signal counted by the counter. If it is determined that the light beam is not properly focused, the controller causes the focusing operation to be performed again. Otherwise, if it is determined that the light beam is properly focused on the data recording layer, the controller causes the tracking operation to be performed and then starts the read operation.

Abstract: A signal quality evaluation method is provided that can objectively evaluate signal quality regardless of a PRML detection method used. The signal quality evaluation method is used when recording and reading is performed by irradiating a medium with a laser beam having a wavelength of ? through an objective lens having a numerical aperture of NA. In the signal quality evaluation method, information of the difference between an ideal signal recoded in the medium and a real signal obtained by irradiating the medium with the laser beam is statistically analyzed for each signal level of the ideal signal. The evaluation of the quality of the real signal is made using the statistics obtained by the statistical analysis.

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: A method for controlling the quality of storage media, and more specifically a method for determining if the quality of a storage medium decreases. The method includes: determining one or more quality parameters of the storage medium; and comparing one or more of the determined quality parameters with previously determined quality parameters of the storage medium stored in a memory in case the quality of the storage medium has been determined before.

Abstract: An optical recording/reproducing apparatus and a data recording method thereof. The optical recording and/or reproducing apparatus includes: an encoder which encodes a data for recording in a specified format; an optical pickup which records the encoded data onto a data record area of an optical recording medium which is loaded in the optical recording/reproducing apparatus; and a controller which allocates a specified area of the optical recording medium as a management information record area, controls the optical pickup to record the management information regarding the data being recorded in the data record area to be recorded in the management information record area, and controls the optical pickup to periodically record the management information of the management information record area onto a file information record area of the optical recording medium.

Abstract: A filter, including a direct-current (DC) tracking unit, a subtracter and a control unit, is provided. The DC tracking unit extracts a DC component of a radio-frequency (RF) signal and accordingly generates a level signal. The subtracter subtracts the level signal from the RF signal to generate a RF coupling signal. The control unit determines whether to transmit a setting signal to the DC tracking unit according to the level variation of the RF coupling signal, so as to adjust a characteristic parameter of the DC tracking unit.

Abstract: Various embodiments of the present invention provide systems, methods and media formats for processing user data derived from a storage medium. As an example, a system is described that includes a storage medium with a series of data. The series of data includes a servo data and a user data region. The user data region includes a first synchronization pattern and a second synchronization pattern located a distance from the first synchronization pattern. A storage buffer is provided that is operable to receive at least a portion of the series of data. A retiming circuit calculates an initial phase offset and frequency offset for a defined bit within the storage buffer using a first location of the first synchronization pattern and a second location of the second synchronization pattern. An error correction loop circuit re-samples the series of data from the storage buffer based at least in part on the initial phase offset and a frequency offset.

Abstract: A reproduction signal evaluation method evaluates the quality of a reproduction signal reproduced from an information recording medium based on a binary signal generated from the reproduction signal using a PRML signal processing system. The method includes a pattern extraction step of extracting, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step of computing a differential metric based on the binary signal; an extraction step of extracting the differential metric which is not greater than a predetermined signal processing threshold; a step of determining a mean value of the differential metrics which are not greater than the signal processing threshold and extracted in the extraction step; a standard deviation computing step of determining a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step of evaluating a quality of the reproduction signal using the standard deviation.

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: An information reproducing apparatus (1) is provided with: an offset adding device (19-1, 19-2) for adding an offset value (OFS) which can be set to be variable, to a read signal (RRF) read from a recording medium (100); a correcting device (18) for correcting waveform distortion occurring in a read signal corresponding to a long mark, of the read signal to which the offset value is added; and a waveform equalizing device (18) for performing a waveform equalization process on the read signal in which the waveform distortion is corrected.

Abstract: A communications node can receive a plurality of communication signals, each including a block of data estimates with respective quality metrics. Each block of data estimates can be derived from an original block of data sent over different wireless paths, or from a derived block of data estimates sent over a different wireless path. A data combining circuit can be used to combines the blocks of data estimates as a function of the respective quality metrics to produce an output set of data estimates with a derived quality metric.

Abstract: To adjust the parameters of a write strategy for recording data on an optical recording medium, the jitter value of a reproduced signal obtained from recorded data is detected. If the jitter value exceeds a prescribed threshold, a write strategy parameter having a comparatively small effect on the jitter value is adjusted, and subsequent data are written on the recording medium using the adjusted parameter. Parameters are selected for adjustment in ascending order of their effect on the jitter value. Stable data recording can thereby be carried out without significant jitter degradation.

Abstract: An information processing device includes: a correction coefficient holding unit configured to hold a correction coefficient which is a ratio between the position of a control target at a start time of control operation, and a detection signal indicating the control result of the control target; an initial-value-compensation matrix holding unit configured to hold an initial-value-compensation matrix for performing compensation of the initial value of a control computing unit for computing control output for controlling the control target from the detection signal based on the position and speed of the control target; and an initial-value generating unit configured to correct the position and speed of the control target at a start time of control operation with the correction coefficient, and employ the position and speed of the control target after correction, and the initial-value-compensation matrix to generate an initial-value-compensation value for compensating the initial value of the control computing u

Abstract: An evaluation apparatus obtains an evaluation value of a signal read from an optical recording medium includes a reading device reading a signal recorded on the optical recording medium. Edge positions are detected of the read signal acquired by the reading device. A frequency distribution table is generated of the edge positions on the basis of an accumulation result of information of the edge positions detected by the edge position detection device. A first calculation of a T degree value is represented as [{?fi×(xi?A)(2m+1)}/F]{1/(2m+1)}??Formula 1 (wherein m is a natural number excluding zero) The variables xi, fi, F, and A represent the value of each of the classes, the frequency of each of the classes, the sum of the frequencies, and the weighted average value, respectively.

Abstract: A device and method for reducing power consumption of an optical drive are proposed. The present invention samples a carrier control signal and then compares the samples of the signals with predetermined threshold signals. According to the comparison result, the present invention increases or decreases an output signal index. The variation of the output signal index is used to control phases of diphase excitation control signals so as to control the rotation direction of a motor or make it stop. The present invention need not output the diphase excitation control signals continuously. It only needs to output a predetermined number of the diphase excitation control signals after the output signal index is increased or decreased. Hence, the present invention reduces the time for outputting the control signals and greatly reduces the power consumption of the optical drive thereby.

Abstract: A method of detecting defects of a recording medium comprises detecting a number of error-corrected error correction code symbols in each of a plurality of sectors in the recording medium, classifying sectors having a number of error-corrected ECC symbols greater than a first threshold value as first type defect sectors, calculating moving averages of the numbers of error-corrected ECC symbols in units of a predetermined number of sectors, and classifying sectors that are used to calculate a moving average greater than a second threshold value as second type defect sectors.

Abstract: A phase error detection apparatus capable of performing offset correction of a tracking error signal accurately even when there is a defect or a non-recorded position on an optical disc. There are provided a phase difference detection circuit (107) which receives two sequences of digital signals, performs phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputs a phase comparison result PCR and a phase comparison completion signal PCC, and an offset control circuit (11) which outputs an offset correction amount for each phase comparison completion signal PCC from the phase difference detection circuit (107), and the offset correction amount ?? is added to the phase comparison result PCR to avoid offset correction in a position where phase comparison is not carried out.

Abstract: Provided is an optical disc device capable of correcting a value of a control parameter during an operation of reading information from an optical disc medium. The optical disc device for reading the information recorded on the optical disc medium under an operation condition corresponding to a value set with respect to a predetermined control parameter corrects the value of the predetermined control parameter by repeatedly executing, while an operation of reading the information from the optical disc medium is being performed, processing of: acquiring, with respect to two values of the predetermined control parameter, evaluation values indicating accuracy of the reading of the information from the optical disc medium, respectively; and updating the value of the predetermined control parameter based on the two acquired evaluation values.

Abstract: An A/D converter samples a read signal in synchrony with a system clock sclk having a fixed frequency, to perform an A/D conversion. A fluctuation compensator is configured as an internal-feedback-type compensation filter, and suppresses fluctuation of a digital signal output from the A/D converter. A digital PLL uses an interpolator to generate, by interpolation, a sampled value of the read signal at a timing in synchrony with a channel frequency, and uses NCO to generate a synchronizing clock and an interpolated-phase signal that is fed back to the interpolator. A binarization circuit binarizes the read signal based on the interpolated value output from the interpolator. The frequency characteristic of the fluctuation compensator is controlled based on the frequency value output from the loop filter.

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: Detecting a defect on a storage device is disclosed. Detecting includes receiving a signal read from a storage device, sampling the signal to obtain a set of signal samples, wherein the sampling starts at an arbitrary time, computing a defect value for a defect type using the set of signal samples, comparing the defect value with a threshold associated with the defect type, determining whether there is a defect of the defect type based at least in part on the comparison, and in the event that a defect is detected, outputting an indication associated with the defect.

Abstract: A system includes a sampling module and a correction module. The sampling module is configured to sample an input signal at sampling points and to output samples. The correction module is configured to output a correction factor when the first one of the samples is preceded by a second one of the samples having a first polarity, and when the first one of the samples is followed by a third one of the samples having a second polarity that is opposite of the first polarity. The correction factor comprises a correction value that is based on at least one of the samples that precedes the first one of the samples. The correction value is used to correct the input signal at a first one of the sampling points corresponding to the first one of the samples.

Abstract: Aspects of the disclosure provide an apparatus. The apparatus includes a pick-up unit, such as an optical pick-up unit, a wobble channel and a defect detector. The pick-up unit generates a push-pull signal corresponding to a wobbled track of a storage medium. The wobble channel includes circuits to receive the push-pull signal, obtain a wobble signal from the push-pull signal, and calculate a wobble amplitude metric based on the wobble signal. The defect detector compares the wobble amplitude metric to a threshold to detect wobble defects.

Abstract: A method for detecting the obliquity of an optical disc drive is provided. The method includes the steps of calibrating balance gains of TE signals and CE signals with predetermined obliquities of the optical disc drive, curve-fitting and storing a relating function between the predetermined obliquities and the balance gains, calibrating the balance gains of signals for an installed optical disc drive, and acquiring an calibrated balance gain to find the obliquity of the optical disc drive from the relating function.

Abstract: A recording and reproducing area and a reproduction-only area are formed by wobbling a groove formed in a spiral fashion to form a track to be tracked on a disk. The recording and reproducing area has address information recorded by wobbling of the groove and information recorded and reproduced by phase change marks on the track formed by the groove where the address information is recorded. The reproduction-only area has prerecorded information recorded by wobbling of the groove.

Abstract: A pre-treating circuit for accessing the disc and a method thereof, which are especially used for treating the signal waveform that violates the encoding rule of the disc information, are provided. The present invention can modulate the signal waveform that violates the encoding rule, so that the waveform is not changed during at least 3 continuous periods of the clock signal. The present invention also replaces any wrong 16-bit data which violate the encoding rule, with approximated 16-bit data before they are decoded, or receives approximated 8-bit data which correspond to the incorrect 16-bit data, by directly referring to a table. Therefore, the subsequent decoding module can acquire more data for continuous processing, so as to improve the data reading reliability and to prevent the “picky disc” or “disc error reading” problem from happening.