Abstract: An optical waveguide is disclosed. The optical waveguide includes a plate of transparent material comprising opposed first and second surfaces for guiding an optical beam between the surfaces by at least one of reflection or diffraction. A diffraction grating is disposed at the first surface for spreading the optical beam by diffracting portions thereof into a non-zero diffraction order to propagate inside the plate. The first diffraction grating includes an array of parallel grooves structured to provide a spatial variation of optical phase of the portions of the optical beam diffracted by the first diffraction grating into the non-zero diffraction order.

Abstract: An optical waveguide is disclosed. The optical waveguide includes a plate of transparent material comprising opposed first and second surfaces for guiding an optical beam between the surfaces by at least one of reflection or diffraction. A diffraction grating is disposed at the first surface for spreading the optical beam by diffracting portions thereof into a non-zero diffraction order to propagate inside the plate. The first diffraction grating includes an array of parallel grooves structured to provide a spatial variation of optical phase of the portions of the optical beam diffracted by the first diffraction grating into the non-zero diffraction order.

Abstract: Aspects of the disclosure provide a sync mark detector. The sync mark detector includes a first unit configured to decay over time a value indicating a length of a bit format, a second unit configured to compare the decayed value with a detected length of the bit format to determine a new length, and a third unit configured to detect a sync mark based on the detected length and the new length.

Abstract: New and useful methods and systems for detecting sync signals/patterns in streams of data are disclosed. For example, in an embodiment system for processing data includes a first module having dedicated processing circuitry configured to detect a sync signal embedded in a received stream of data and to produce an output stream of data, and second module that includes a firmware-controlled processor configured to correct sufficient errors within the received stream of data so as to allow the first module to detect the sync signal on a condition when the first module by itself is incapable of resolving the sync signal caused by the errors in the received stream of data.

Abstract: A method and device for determining frequency error to extend the pull-in range of a timing recovery circuit for a storage device such as an optical disc drive. A code associated with a storage format of the storage device is detected, and the distance between occurrences of the code is determined. The calculated distance is compared with the expected distance to determine the difference. Based on the difference, the frequency error is determined.

Abstract: New and useful methods and systems for detecting sync signals/patterns in streams of data are disclosed. For example, in an embodiment system for processing data includes a first module having dedicated processing circuitry configured to detect a sync signal embedded in a received stream of data and to produce an output stream of data, and second module that includes a firmware-controlled processor configured to correct sufficient errors within the received stream of data so as to allow the first module to detect the sync signal on a condition when the first module by itself is incapable of resolving the sync signal caused by the errors in the received stream of data.

Abstract: A method and device for determining frequency error to extend the pull-in range of a timing recovery circuit for a storage device such as an optical disc drive. A code associated with a storage format of the storage device is detected, and the distance between occurrences of the code is determined. The calculated distance is compared with the expected distance to determine the difference. Based on the difference, the frequency error is determined.

Abstract: Disclosed herein is a reception apparatus, including an acquisition section adapted to receive a signal which includes at least one of a first signal and a second signal which have different structures from each other except that the first and second signals have a preamble signal and acquire the preamble signal from the received signal; a detection section adapted to detect a value for correcting the signal using the signal; and a correction section adapted to correct, if it is decided based on the preamble signal acquired by the acquisition section that the signal is the first signal, the signal using the value detected by the detection section.

Abstract: Analog components whose characteristics greatly differ from one another are removed as much as possible from an optical disc drive. Provided are means 38, 39 for changing the sampling frequency of a pulsed read signal to a different frequency, means 40, 41 for changing the modulation clock frequency by the same ratio as the sampling frequency, and means for automatically setting the sampling frequency changing means and the modulation clock changing means based on the channel clock.

Abstract: Provided are an optical disc recording device and a recording signal generating device which enable to correct displacement between a reproducing position of a reproduction signal from a concave-convex mark preformed in an optical disc, and a recording position of second information to be recorded in synchronism with the reproduction signal, and stably and speedily record the second information. A digital signal processor (202) specifies a reproducing position in the concave-convex mark, using a reproduction signal and a channel clock. A recording signal generator (211) generates a recording signal alternately including a plurality of additionally recordable data, each of which includes second information and has a predetermined length, and a plurality of dummy data.

Abstract: A method and device for determining frequency error to extend the pull-in range of a timing recovery circuit for a storage device such as an optical disc drive. A code associated with a storage format of the storage device is detected, and the distance between occurrences of the code is determined. The calculated distance is compared with the expected distance to determine the difference. Based on the difference, the frequency error is determined.

Abstract: A method and an apparatus for data storage based on fibers are described. Data are stored as marks in a surface of a fiber or in a volume near the surface of the fiber. Data marks are written to or read from the fiber by irradiating the surface of the fiber with at least one radiation beam. The fiber has calibration marks for controlling a speed of the fiber relative to the at least one radiation beam.

Abstract: An asynchronous timing detector 3 detects and measures a specific pattern (sync pattern) of audio and video reproduced signals having a digital value form an A/D converter 2 and its appearance interval based on an asynchronous clock generated by an asynchronous clock generator 4, and calculates a cycle ratio of the measured sync pattern appearance interval (the number of clock pulses of the asynchronous clock) to a normal value (the number of clock pulses of a synchronous clock obtained by measuring a sync pattern appearance interval using the synchronous clock). A pseudo-synchronous clock generator 7 thins the asynchronous clock based on the cycle ratio to generate a pseudo-synchronous clock which is pseudo-synchronous with channel data. Therefore, even when an initial frequency error is large, frequency and phase pull-in is relatively quickly performed until a timing recovery operation becomes stable.

Abstract: An apparatus for detecting burst cutting areas on optical discs includes an optical pickup head, a front-end processing unit, a sync pattern detector, a channel clock recovery device, and a data demodulator. The front-end processing unit generates a BCA signal in response to a radio frequency signal. The sync pattern detector counts the BCA signal according to a reference clock, detects a sync pattern of the BCA signal and outputs a channel bit length counting value. The channel clock recovery device generates a channel clock according to the reference clock and the channel bit length counting value. The data demodulator transfers the BCA signal into a BCA data according to the channel clock. The sync pattern detector continuously counts the BCA signal and continuously outputs a plurality of counting values, so that the sync pattern of the BCA signal can be determined according to at least three sequential counting values.

Abstract: In a coupled ring oscillator including q ring oscillators each including p inverter circuits connected together to form a ring shape, and a phase coupling ring including (p×q) phase coupling circuits each of which is configured to couple an output of one of the p inverter circuits of one of the q ring oscillators to an output of one of the p inverter circuits of another one of the q ring oscillators in a predetermined phase relationship, and which are connected together to form a ring shape, for at least one group made up of one of the p inverter circuits in each of the q ring oscillators, outputs of the q inverter circuits belonging to the at least one group are fixed in phase with one another, the q ring oscillators are caused to oscillate in the in-phase fixed state, and then, the outputs of the q inverter circuits are released from the in-phase fixed state.

Abstract: An address detection circuit includes a correction signal generator that generates a plurality of timing correction signals based on an ADIP (Address In Pre-groove) signal that is read out from a wobble of an optical disk, the timing correction signals having different cycles with each other, a correction signal selector that selects one of the timing correction signals generated by the correction signal generator and outputs the selected signal, and a timing corrector that outputs a data address detected based on a data signal that is read out from a data track of the optical disk at a timing in accordance with the timing correction signal transmitted from the correction signal selector.

Abstract: This invention provides an optical storage device for recording a plurality of data onto an optical storage medium. If recording interrupted, the optical storage device generates a data-interrupted address, and re-connects the interrupted data with a data re-connecting physical address. The optical storage device comprises a physical addressing module, a record-interrupt generator, a data recording controller, a data-interrupt address generator and a data-reconnecting physical address generator. The physical addressing module provides a reference physical address for recording data onto the optical storage medium. When detecting the interrupt of data recording, the data-interrupt address generator generates the address of the interrupted data. According to the address of the interrupted data, the data-reconnecting physical address generator generates a data-reconnecting physical address.

Abstract: A sync finder includes a pulse jitter detect module to select N-bit segments of an M-bit sync pattern at predetermined positions and to compare the N-bit segments to expected N-bit segments. A pulse verifying module generates a first signal in response to the expected N-bit segments matching the N-bit segments. N and M are integers greater than 1 and M>N.

Abstract: Aspects of the disclosure provide a method for recording. The method includes receiving a tracking signal corresponding to a recording track on a storage medium, phase-locking an internal signal to the tracking signal by reducing a phase error generated based on the internal signal and the tracking signal, generating a phase bias, combining the phase bias into the phase error to phase-shift the internal signal from the tracking signal, and recording on the recording track based on the internal signal.

Abstract: The present invention sets forth a method and a system for calibrating optimized power of an optical pick-up unit of an optical disk drive. The system comprises a micro-processor, and a signal processor. The micro-processor coupled to the optical pick-up unit sets an initial power corresponding to an optical disk, and calculates a predetermined number of power levels to cover the range of the initial power for performing a recording procedure. The signal processor coupled to the micro-processor determines whether a servo state failed during optimized power calibration, and calculates recording performance of each power level. The signal processor transmits the servo state and the recording performance to the micro-processor for determining the optimized power.

Abstract: A recording/reproducing apparatus (100) is provided with comprising: recording devices (131a-131e) for recording record signals (WS1-WS5) in parallel and in synchronization with a record clock; a signal generating device (143) for generating record signals such that a reproduction clock synchronized with the record clock can be generated on the basis of the reproduced record signals, if the plurality of record signals are reproduced in parallel; reproducing devices (131a-131e) for reproducing the record signals in parallel; and a clock generating device (154) for generating a reproduction clock.

Abstract: An oscillation circuit includes: n ring oscillators each formed from m delay elements connected annularly, m being an integer equal to or greater than 2, n being an integer equal to or greater than 2; and a phase coupled ring.

Abstract: A data writing device for preventing a phase-change optical disc from deteriorating due to repeated writing and for preventing the rewritable number of times of the disc from decreasing. The device writes data including synchronization frames to the disc. Each synchronization frame includes a primary or secondary synchronization signal. A comparator compares a first accumulated DSV for specifying the data including the primary synchronization signal for the synchronization frame with a second accumulated DSV for specifying the recording data including the secondary synchronization signal for the synchronization frame and generates a first selection signal based on the comparison. An inverter randomly inverts the first selection signal to generate a second selection signal. A selection circuit receives the primary and secondary synchronization signals and outputs the primary or secondary synchronization signal in response to the second selection signal.

Abstract: The present disclosure can provide a method and an apparatus to correct wobble phase slip in an optical disc recording system during recording. The method of correcting a phase slip can include receiving a wobble signal of a first frequency, sampling the wobble signal to generate a sampled wobble signal, where the wobble signal is sampled at a second frequency that corresponds to a frequency of a sampling signal, comparing a phase of the sampled wobble signal with a phase of a controlled signal to generate a phase error, modifying the phase error by adding a phase bias, and adjusting the second frequency based on the modified phase error to reduce a magnitude of the modified phase error.

Abstract: A pickup control device includes a servo system which processes a first signal for error control read from an optical disk to generate a servo control signal. A clock signal is synchronized with the rotation of the optical disk. Two memories store a frequency component at or lower than a predetermined frequency contained in the first signal and a rotational frequency component contained in the first signal. A first adder adds data from the first memory to the first signal and a second adder, in synchronization with the clock signal, data from the memories to generate a second signal. A correction unit writes into the second memory the frequency component or the rotational frequency component and reads data and supplies data to the first adder, and reads and updates data stored in the first memory.

Abstract: A digital loop filter receives a phase error output from a phase comparator to generate a digital frequency value. This digital frequency value is converted into an analog voltage by a D/A converter, and VCO outputs a synchronizing clock of frequency corresponding to the voltage output from the D/A converter. The phase error output from a phase comparator is gain-corrected by a product of an output from the digital loop filter and a specific coefficient “A”, and delivered to digital loop filter. The phase error input to the digital loop filter is changed in proportion to the output clock frequency, whereby the PLL loop as whole linearly controls the loop characteristic depending on the output clock frequency.

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 frequency control device capable of detecting a frame sync pattern and generating a frequency information accurately even if a reproduction signal is not zero-crossed, and an information reproduction apparatus having the same, which includes an oscillation circuit outputting a clock having a frequency corresponding to a control signal; a converter sampling an input analog signal having a predetermined pattern based on the clock and converting the same to a digital signal; and a frequency detection device detecting an object to be a sync pattern from a changing trend of the digital signal, generating a frequency information for controlling a reproduction clock based on the detected object to be the sync pattern, and outputting the same as the control signal to the oscillation circuit.

Abstract: The present invention relates to a method for controlling a LBR (Laser Beam Recorder) (56) suitable for mastering a record carrier (60) by writing data in the record carrier in circular or spiral tracks and comprising: means (58) for rotating a record carrier; means (62) for moving a laser (61) over the record carrier (60) in a radial direction with reference to the rotation of the record carrier (60); means (65) for controlling the laser output power; and means (66) for synchronizing the rotation of the record carrier (60), the movement of the laser (61) and the laser output power. In accordance with the invention synchronizing the rotation of the record carrier 60; the movement of the laser 61 and the laser output power is performed such that at least a part of the data is written in at least one track comprising a different arrangement than circular or spiral. The present invention also relates to a Laser Beam Recorder.

Abstract: There is provided an information recording/reproducing apparatus for recording or reproducing an information to or from an information recording medium having a plurality of recording layers stacked on a substrate which can always perform stable spindle rotation control irrespective of an error of a desired frequency value or the like, and which includes an optical head for recording or reproducing an information to or from the recording layers by use of an optical beam; a spindle motor for rotating the recording medium; and a drive voltage holding circuit for holding a drive voltage of the spindle motor when the optical head performs switching between the recording layers for recording/reproducing.

Abstract: To provide a disk reproducing apparatus capable of reading data at a lower error rate without requiring a complicated circuit configuration. An embodiment of the present invention provides a disk reproducing apparatus for reproducing a data signal based on a signal read from a disk and having a clock cycle that is an integral multiple of a cycle of a reproduction clock, including: a clock generating unit generating the reproduction clock based on an input signal obtained by binarizing the signal read from the disk; an error component detecting unit detecting an error component in the input signal; a threshold storage unit storing a threshold value for determining the error component; and a data signal reproducing unit reproducing the data signal in the input signal based on the error component detected by the error component detecting unit and the threshold value stored in the threshold storage unit.

Abstract: A playback apparatus plays back information from a recording medium having a data structure including sync signals added in units of data items each having a predetermined size. The information is recorded in runlength limited codes, and the signals correspond to consecutive unique run lengths. The apparatus includes an information reading unit that obtains a binary data string as read information by reading the medium, a sync detection unit that performs detection of sync signals from the data string, and a data demodulation unit that obtains played-back data from the medium by performing demodulation on the data string with timing based on the detected signals. On the basis of detection, from the data string, of one detection pattern among types of detection patterns set as patterns including at least one of the unique run lengths, the sync detection unit regards the pattern detection as the signal detection.

Abstract: A high-density optical disc, a method for encrypting data and recording the encrypted data thereon, and a method for reproducing the encrypted data recorded thereon. Data recorded on a high-density optical disc such as a Blu-ray disc-read only memory (BD-ROM) is recorded in a discontinuous recording format as on a high-density rewritable optical disc such as a Blu-ray disc rewritable (BD-RE). Data can be encrypted and recorded using synchronous data, address unit number (AUN) information or disc radius information recorded in the high-density optical disc. An optical disc apparatus such as a BD-ROM player can maintain reproduction compatibility with the high-density rewritable optical disc such as the BD-RE. A user holding an optical disc apparatus such as a BD-RE recorder, etc. can be prevented from unlawfully copying data recorded on the high-density optical disc and reproducing the copied data.

Abstract: An information signal is read from a recording medium to generate a reproduced signal. A sync detector detects a sync signal in the reproduced signal on a pattern search basis during operation in a direct mode. The sync detector sets a detection window and detects a sync signal in the reproduced signal in the detection window during operation in an inertia mode. A special pattern signal in the reproduced signal is detected and counted to generate a count result. The count result is reset in response to detection of a first special signal in the reproduced signal. A detection flag is generated in cases where a second special signal in the reproduced signal is detected when the count result denotes a last sector in a block of the reproduced signal. The sync detector changes its operation from the inertia mode to the direct mode when the detection flag is generated.

Abstract: A sync finder module for an optical medium playback device that generates a bit stream including sync patterns and data blocks comprises a pulse jitter detect module that receives the sync pattern, which includes a plurality of transitions each having a desired position in the sync pattern, that selects actual N-bit segments of the sync pattern at the desired positions and that compares the actual N-bit segments to at least one expected N-bit segment. A pulse verifying module communicates with the pulse jitter detect module and generates a verified signal if the expected N-bit segments match the actual N-bit segments.

Abstract: A high-density optical disc, a method for encrypting data and recording the encrypted data thereon, and a method for reproducing the encrypted data recorded thereon. Data recorded on a high-density optical disc such as a Blu-ray disc-read only memory (BD-ROM) is recorded in a discontinuous recording format as on a high-density rewritable optical disc such as a Blu-ray disc rewritable (BD-RE). Data can be encrypted and recorded using synchronous data, address unit number (AUN) information or disc radius information recorded in the high-density optical disc. An optical disc apparatus such as a BD-ROM player can maintain reproduction compatibility with the high-density rewritable optical disc such as the BD-RE. A user holding an optical disc apparatus such as a BD-RE recorder, etc. can be prevented from unlawfully copying data recorded on the high-density optical disc and reproducing the copied data.

Abstract: A recording apparatus detects a preamble, which is a series of patterns formed on a track, and generates a clock based on the preamble. The recording apparatus then detects a Sync mark, which is a predetermined pattern formed between the preamble and a Resync mark, calculates a predicted position of the next Resync, and switches PLL gain to a low level. The recording apparatus then detects the Resync mark, which is a pattern of equal to or more than one pulse, and corrects the generated clock. Specifically, upon detecting the Resync mark, the recording apparatus compares a timing of the predicted position of the Resync, and the timing at which the Resync mark is actually detected to correct a write clock.

Abstract: An apparatus is provided for writing reference patterns on a data storage disk of a disk drive. The disk is rotated by a spindle motor. A back EMF sense circuit generates a sequence of zero crossing signals from back EMF sensed on windings of the spindle motor over each revolution of the spindle motor. The sequence of zero crossing signals define a corresponding sequence of zero crossing periods of time between successive zero crossing signals. A Phase Locked Loop (PLL) circuit generates a timing signal in response to comparison of a feedback signal to the zero crossing signals. The PLL circuit also compensates for repeatable variation among the sequence of zero crossing periods over each revolution of the spindle motor so that the timing signal is substantially independent of the repeatable variation among the sequence of zero crossing periods. A recording pattern generator writes reference patterns on the disk in response to the timing signal as the disk is rotated by the spindle motor.

Abstract: Data having a basic data length of m bits is modulated to a variable-length code having a basic code length of n bits. A sync signal is added to the data after a minimum bit-run in the data. The sync signal exhibits two or more patterns, each pattern breaking a maximum bit-run and having six channel bits for identifying each sync signal. The two or more patterns are distinguished from one another, with a detection distance of at least two therebetween.

Abstract: An apparatus for preventing a writing error from occurring on an optical disc. The apparatus includes an interpolation ATIP sync signal detector, a number determiner, and a writing speed adjuster. The interpolation ATIP sync signal detector receives a wobble signal from the wobble signal generator of an optical disc drive to detect an interpolation ATIP sync signal from the wobble signal. The number determiner determines a number of interpolation ATIP sync signals and generates a writing speed transformation control signal based on the determination result. The writing speed adjuster receives the writing speed transformation control signal from the number determiner to adjust a writing speed of the optical disc drive.

Abstract: An optical disk apparatus for recording data on an optical disk having a land pre-pit (LPP). An encoder of a DVD-R/RW drive records data while inserting synchronization information having a length of 14T at the top of a synchronous frame. The encoder sets synchronization information of the i-th frame (wherein i is an integer which is 0 or greater) and the (i+1)th frame of a plurality of consecutive frames to either a mark or a space such that each DSV is minimized. The encoder sets the synchronization information of the (i+2)th frame such that the polarity of the synchronization information of the (i+2)th frame is opposite to the polarity of the synchronization information of the i-th frame, and sets the synchronization information of (i+3)th frame such that the polarity of the synchronization information of (i+3)th frame is opposite to the polarity of the synchronization information of the (i+1)th frame.

Abstract: A detection apparatus of an optical storage device for detecting a synchronization signal includes a sampling module for sampling a disc signal to generate a plurality of sampled data, a comparing module coupled to the sampling module for comparing the sampled data and a synchronization pattern to generate a first compared result and to generate a second comparing result after a time interval, and an adjusting module coupled to the comparing module for gathering a statistic of the first and the second comparing results to generate an adjusting signal for adjusting a phase of the sampling clock.

Abstract: A writing method for an optical disc to optimize a writing speed, wherein a spiral track on the optical disc is divided into a plurality of zones, and different CLV writing speeds are used for performing a ZCLV writing to the zones respectively. The writing method comprises steps of: setting a plurality of writing modes; storing a plurality of zone parameter sets for the writing modes respectively in a memory, wherein each of the zone parameter sets comprises dividing times for dividing the zones, and the different CLV writing speeds for the zone respectively; determining a disc type of the optical disc by a disc type determining device before the ZCLV writing is performed; selecting one of the zone parameter sets that is suitable to the disc type of the optical disc; and performing the ZCLV writing with the writing mode corresponding to the selected zone parameter set.

Abstract: The invention provides a data recording device comprising: an interval counter; an ? counter; and a segment counter, wherein the interval counter and the ? counter operate with a clock having a constant frequency which is independent of clock information, the interval counter is reset when division information is detected and, also, is reset and activates the ? counter when it reaches a count value corresponding to a segment length, the ? counter is reset when the division information is detected and, also, is reset and increments the count value of the segment counter when it reaches a count value corresponding to a predetermined length smaller than the segment length, and the segment counter increments its count value when the division information is detected and outputs a writing inhibition signal when it reaches a count value corresponding to the frame length.

Abstract: A detector and a method for detecting synchronization signals in a disc system are disclosed. The method includes sampling a disc signal with a sampling clock to generate a plurality of sampled data, comparing the plurality of sampled data with a predetermined synchronization pattern to generate a comparison result, performing the above-mentioned comparing step after a predetermined time interval, and outputting a synchronization signal and adjusting the time for outputting the synchronization signal according to the comparison results.

Abstract: A clock generation method detects from servo signals a degree of decentering of a patterned medium having recording pits arranged in a circular pattern and changes a clock frequency for recording/reproduction based on the detected degree of decentering.

Abstract: A media player having variable pitch is disclosed. The player incorporates a memory buffer that is responsive to a user-designated pitch adjustment. The result is that a user can manually control and adjust the pitch of prerecorded CDs and MP3s or other digital media in an “on-the-fly” environment.

Abstract: A system and method of switching the control modes of spindle motor are described. The switch system comprises a first control module, a second control module and a switch controller. The first control module electrically coupled to the spindle motor and the OPU controls the spindle motor to be operated in a present mode. The second control module is electrically coupled to the spindle motor to control the spindle motor to be operated in the transition mode between the present mode and the target mode. The switch controller electrically coupled to the first control module, the second control module and the spindle motor receives a present feedback signal associated with the rotation of spindle motor to generate a first switch signal. Furthermore, the switch controller receives a target indicative signal associated with the information on the optical storage medium to generate a second switch signal.

Abstract: A method and device for recording information signals on a partly recorded writable record carrier (11), e.g., an optical disc. An information signal represents at least one information unit. The record carrier has a recording track which includes preformed track position information indicative of locations for recording the information units. From the information signal, a modulated signal is generated having successive frames, each frame including a synchronizing signal. The modulated signal is recorded at a one of the locations, while maintaining a fixed relationship between the track position information and the synchronizing signals. In the event that the location is after and adjacent to an already recorded location, the recording is started at a link position (31) before the end of a last frame of the earlier recorded information signal, at a predefined distance before a first synchronizing signal (30) of the modulated signal.

Abstract: A method for optical drive decoding of address in pre-groove (ADIP) data is provided to decode an input wobble signal to an ADIP unit signal. The method includes generating a wobble carrier frequency signal having the same phase with the wobble signal, multiplying the wobble carrier frequency signal by the input wobble signal to generate a product signal, accumulating the value of the product signal in each clock to generate a quotient summation signal, determining the phase change of the input wobble signal according to the value of the quotient summation to generate a phase change signal, and generating the ADIP unit signal by comparing the phase change signal with a plurality of ADIP patterns.