Abstract: The present invention provides for a method for reducing undesirable skipping during playback of a compact disc in a compact disc player. A lens system of the compact disc player reads audio data and subcode data from the compact disc. The subcode data includes Q channel bits and P channel bits. The actual time lapse of the compact disc playback is calculated from the Q channel bits and the P channel bits, while a target time lapse is calculated based on data received from a real-time clock. The difference between the two time lapse values is calculated, and if the differences is greater than a predetermined threshold, the lens system is repositioned to read the audio data from the compact disc corresponding to a predetermined time interval in advance of the current position of the lens system.

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 data reproducing apparatus, which is capable of reproducing stream data according to time stamps without need to have an independent time counting clock. At step S141, it is determined whether a received access unit has a time stamp. When the access unit has a time stamp, the flow advances to step S142. At step S142, a value of the time stamp is set. When the access unit does not have a time stamp. The flow advances to step S144. At step S144, a value corresponding to the previous pic_struct is added to the current time. Thereafter, the flow advances to step S143. At step S143, the current pic_struct is stored for the next process. The present invention is capable of being applied to for example a game device using a DVD.

Abstract: Where a clock frequency based on which encoding is performed has deviated over time, problems such as that an appropriate digital signal can not be outputted occur. To solve the problems, it is arranged such that when a decoder decodes video data and audio data, a control variable for controlling a frequency of a clock recovered by a clock generating portion is recorded as needed in a recording portion, and when the decoder decodes data recorded in the recording portion, the clock generating portion is controlled by using the control variable so that system time information generated by the counter synchronizes with time information extracted upon reception of a digital broadcasting program.

Abstract: According to one embodiment, an optical disc device includes a light source portion which applies laser light to an optical disc, a drive portion which supplies a drive current to the light source portion so as to cause the light source portion to apply laser light of light pulses having relaxation oscillation, and a controller which controls the drive portion to supply a drive current so as to cause the light source portion to emit laser light of (n?1)×N (N is an integral number) light pulses having relaxation oscillation with respect to a mark with recording mark length nT (n: integral number, T: channel clock) to be recorded on the optical disc.

Abstract: When generating a sampling clock of an A/D converter for digitizing a playback signal from an optical disc, an over sampling clock generated by a PLL is used. Further, zerocross position information and reference information of a playback digital signal that is obtained by A/D conversion using the over sampling clock are converted into those synchronized with the channel bit clock by an operation cycle conversion unit, and then supplied to a PRML signal processing unit and a level judgement binarization unit.

Abstract: A phase difference detection circuit that is formed by digital circuits having a small circuit area. In the phase difference detection circuit, the circuits for generating a tracking error signal are structured by digital circuits, and a digital tracking error signal TE is generated from digital signals output from comparators. The latest previous phase difference data are stored in a phase difference memory, and a phase difference window PW is defined from the average phase difference calculated from the stored phase differences.

Abstract: An information processing apparatus capable of reducing propagation delay differences and error factors, capable of realizing high precision binarization control, and accordingly capable of realizing high precision reproduction, including a comparator for converting an RF signal to a binarized signal; an edge position measurement unit for measuring the edge position of the binarized signal in a time axis by multi-phase clocks; a jitter measurement unit for measuring the amount of jitter based on the edge position information; an edge interval measurement unit for measuring the edge interval length based on the edge position information; a propagation delay difference control amount calculation unit for controlling propagation delay amount between an input and an output of the comparator by injecting a slice level voltage of the comparator through a DAC based on the measured amount of jitter and edge interval length; and a channel data discrimination unit for reproducing the data corresponding to the channel c

Abstract: There is provided an information recording and reproducing method and an apparatus for the same capable of optimizing the shift adjustment of a recording pulse recorded in an optical disk even at the time of recording information on the optical disk at a high speed. The shift adjustment value of the recording pulse optimized at a low speed recording on an optical disk is multiplied by a constant value to be taken as the optimum shift conditions of the recording pulse at the high speed recording.

Abstract: Apparatus and methods are provided for detecting the presence of data in a recording media in a plurality of data locations. A mechanical detector is used to sense a data location and generate an initial signal. A differentiator is provided to differentiate the initial signal to generate a derivative signal. A comparator is used for comparing the derivative signal to a first reference signal to determine a zero crossing point representative of a change in direction of the detection device. At least one qualified signal is generated from the derivative signal. Timing circuitry is provided for comparing the zero crossing signal to the at least one qualified signal to determine the presence of data at a data location.

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: 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: A push-pull signal is detected from light reflected from a disk-shaped storage medium on which wobbling grooves are formed as recording tracks and address information is recorded by forming pre-pits on lands between adjacent grooves. A fundamental amplitude variation signal indicating the fundamental amplitude variation of the push-pull signal is acquired, and a reference voltage is generated by adding an offset voltage to the fundamental amplitude variation signal. Pre-pits are detected by comparing the push-pull signal with the reference voltage. Because the reference voltage is produced on the basis of the fundamental amplitude variation signal indicating the variation components of the push-pull signal due to the wobbling of grooves and noise, the variation components due to the wobbling and noise are reflected in the reference voltage. Furthermore, the variation components of the push-pull signal corresponding to the pre-pits are also reflected to a properly small extent in the reference voltage.

Abstract: A method and an apparatus for detecting BCA on the surface of an optical disc are disclosed. The method includes utilizing an internal free running clock to detect a sync pattern, starting demodulation of data on detection of sync ID 1 by utilizing the internal free running clock, and utilizing the transition between row boundaries to determine which sync ID 1 was used for initializing demodulation.

Abstract: The length of a format modulation area in an address segment is limited to be 25% of the address-segment length or less, and the position of the format modulation area is selectable two possible positions. Subsequently, where a CLV optical-disk medium is used, wobble modulation areas in adjacent recording tracks do not overlap each other in the radius direction.

Abstract: The present invention provides a record media, and more particularly, to a method of recording disc identification information within a management area of a recordable optical disc and an optical disc recording/reproducing method using the same. In recording optical disc identification information within a disc management area, the present invention includes recording a media type identification information identifying a type of a record media of an optical disc and a disc manufacturer identification information identifying a manufacturer of the optical disc, respectively. Accordingly, the present invention provides various specified methods of recording disc identification information within a management area in a high-density optical disc, thereby enabling to efficiently cope with the recording/reproducing of the optical disc using the recorded identification information.

Abstract: A phase-locked loop circuit that generates a clock signal synchronized with an input signal with a predetermined frequency, including an oscillator configured to oscillate and generate the clock signal; a converter configured to convert the input signal into a digital signal using the clock signal generated by the oscillator as a sampling clock; a frequency divider configured to divide a frequency of the clock signal generated by the oscillator to generate a comparison clock signal and send the comparison clock signal as a feedback; a normalizer configured to normalize an amplitude value of the digital signal generated by the converter; and an oscillation controller configured to control a phase of the clock signal generated by the oscillator so as to reduce a phase difference between the normalized digital signal generated by the normalizer and the comparison clock signal sent as a feedback by the frequency divider.

Abstract: In an optical disk of HD-DVD, data is recorded in both grooves and lands. A groove track includes its own data region called a groove (G) track address system formed therein and a land track includes its own data region called a land (L) track address system formed therein. One bit of address data is composed of four redundant wobble waves. When only three or two of the four wobble waves can be detected, an error is determined. When an error is determined in tracing of a groove track, bit data of the L track address system is used to correct the error. When an error is determined in tracing of a land track, bit data of the G track address system is used to correct the error.

Abstract: An optical disk read signal processing system for Blu-ray disc systems to ensure stable phase-locked locked operation even with a low signal-to-noise ratio. This system changes a loop configuration of a phase lock loop circuit according to the operating state, and utilizes a FIR equalizer for phase detection. This system attains a low error rate even when the signal-to-noise ratio of an input signal is low, and avoids pulse edges with low phase detection accuracy or signal pulse streams with a high possibility of being mistakenly detected as an edge in conventional methods, and also supports diverse types of input signals.

Abstract: An information recording apparatus such as an optical disc that can avoid an unrecordable condition between a power-on operation and an available state for recording thereby to solve a problem that an image taking chance is missed in a recording step, wherein its constitution is such that: receiving a command to turn on the apparatus after switching, a system controller drives a power-supply circuit to activate a drive controller and a memory controller; if the optical disc is not replaced while in power-off operation by a sub-battery, the system controller issues a request for high-speed activation, based on information stored in an EEPROM, to the drive controller, and drives plural drive control units one after another thereby to establish an activation period confirmedly, allowing the memory controller to accept a request for a recording start from the system controller without waiting for a report of activation completion to be issued by the drive controller.

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 write signal control circuit in an optical disk drive for adjusting the duty cycle of the write signals by a duty cycle adjusting unit. The write signal control circuit includes a write signal generator for converting an EFM signal into the write signals according to the write strategy waveform generating rules, a duty cycle adjusting unit for adjusting the duty cycle of each write signal according to adjusting parameters and for outputting adjusted write signals, and a duty cycle detector for detecting the duty cycle of each adjusted write signal and outputting a respective duty cycle control signal. The duty cycle adjusting unit further receives the duty cycle control signal to adapt the adjusting parameters.

Abstract: The invention relates to an optical drive (10) and a method for determining a reading and/or writing position of an optical drive (10). The optical drive (10) in accordance with the invention comprises control means (12) and at least three PLL units (20, 22, 24), wherein the control means (12) are adapted to control the three PLL units (20, 22, 24) to try to lock on to three different frequencies characteristic for an optical disc (26). The method in accordance with the invention comprises the step of controlling at least three PLL units (20, 22, 24) to try to lock on to three different frequencies characteristic for an optical disc (26). If the optical disc (26) is a Blue Ray Disc, the three different frequencies can be the HFM frequency, the wobble frequency, and the expected HF frequency.

Abstract: A method for recording control information on a recording medium. The method includes generating control information for controlling recording/reproducing data on/from the recording medium. The control information includes a first speed information indicating a maximum recording speed, a second speed information indicating a minimum recording speed, and a third speed information indicating one or more basic recording speeds. The third speed information represents whether each of the basic recording speeds are applicable to the recording medium or not. Thereafter, the method calls for recording the control information on a specific area of the recording medium.

Abstract: A counter 11 continuously reads in the EFM signal from a binarizing circuit 4, resets its count value each time the polarity of the EFM signal changes, counts counter clocks higher in frequency than the EFM signal during each EFM period of the EFM signal, and transfers the count values to a FIFO 12 sequentially. The FIFO 12 temporarily stores the count values transferred, and writes a predetermined number of count values into a buffer RAM 7 in a batch each time the predetermined number of count values are stored.

Abstract: A method for recording/reproducing data on/from a recording medium. The method provides for reading/recording speed information from a specific area of the recording medium, where the recording speed information includes a first information indicating a maximum recording speed, a second information indicating a minimum recording speed, a third information indicating a predetermined recording speed different from the maximum or minimum recording speed, and a fourth information indicating a basic recording speed. Thereafter, the method provides for recording/reproducing the data on/from the recording medium according to the reading/recording speed information.

Abstract: The present invention provides highly reliable PLL without influence of variations in amplitude of a reproduced signal or variations in inclination of an edge. An information-reproducing apparatus according to the present invention includes a unit for detecting a phase difference between a reproduced signal and a reproducing clock signal, a PLL circuit for regulating a frequency of the reproducing clock signal to compensate for the detected phase difference, a unit for detecting a state of the PLL circuit, and a unit for regulating a loop gain of the PLL circuit corresponding to the detected state.

Abstract: An aligned write signal generator with alignment calibration utilizes an alignment unit to align a plurality of write signal. The aligned write signal generator includes a write signal generator for receiving an EFM signal and converting the EFM signal into a plurality of write signals according to a write strategy waveform generating rule, an alignment unit for receiving the plurality of write signals, aligning the write signals and outputting phase adjusted write signals, and a phase calibration unit for receiving the phase adjusted write signals, detecting phase error between the phase adjusted write signals, and outputting phase control signals. The alignment unit further receives the phase control signals to adjust the delay time of each write signal.

Abstract: A playback device for information data sets with a microphone, a memory arrangement, and a control unit. The audio markers are recorded with the microphone. The memory arrangement stores the audio markers in association with the respective information data sets. Furthermore, a control unit is coupled to the memory arrangement and to the microphone. In the method of operating the playback device for information data sets, the recognition of an information data set without an associated audio marker triggers the recording of an audio marker, and the newly recorded audio marker is stored in association with the relevant information data set.

Abstract: A recording control apparatus includes a waveform rectification section for receiving a digital signal generated from an analog signal representing information reproduced from an information recording medium, and rectifying a waveform of the digital signal; a maximum likelihood decoding section for performing maximum likelihood decoding of the digital signal having the waveform thereof rectified, and generating a binary signal representing a result of the maximum likelihood decoding; a reliability calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the digital signal having the waveform thereof rectified and the binary signal; and an adjusting section for adjusting a shape of a recording signal for recording the information on the information recording medium based on the calculated reliability.

Abstract: A PLL circuit having an analog-to-digital converter; a phase error detecting circuit; and an oscillator, in which the phase error detecting circuit includes: phase error detecting means detecting a phase error from a data stream signal and a data stream signal 1 clock cycle earlier; absolute value comparing means detecting an absolute value of the phase error detected exceeding a predetermined threshold; holding means holding a polarity of the phase error, as of a timing of the detection by the absolute value comparing means, for a period of the detection; anticoincidence detecting means detecting anticoincidence between the polarity held by the holding means and a polarity of the phase error detected by the phase error detecting means; and polarity inverting means that provides the phase error detection signal by inverting the polarity of the phase error in detection of anticoincidence, or without inverting the polarity in detection of no anticoincidence.

Abstract: When writing data to an optic disc with a constant linear velocity, and encountering a disc error, data is written into the defect management area of the disc without changing the rotational speed of the disc, or at least without changing the rotational speed of the disc sufficiently to maintain a constant linear velocity. This allows an increase in the rate at which data may be written to the optical disc. It also avoids or reduces the need for the rotational speed of the disc to be changed, which allows a further improvement in the time taken to write data to the disc. In order to continue writing data to the disc without changing the rotational speed, the data rate must be increased while writing to the defect management area. For this to be possible, the data must be written into an “iced” or unformatted part of the defect management area.

Abstract: An optical recording method and apparatus with different recording rates are provided for effectively increasing the average recording rate. The optical recording method includes the steps of: controlling a recording rate with a constant linear velocity (CLV) control mode; recording data; judging whether the recording rate has to be increased according to a rotating speed of a spindle motor or a recording position; and performing a process for changing the rotating speed if the recording rate is increased, and continuing recording data at the same recording rate if the recording rate is not increased. The step for changing the rotating speed includes the steps of: pausing recording data; registering a paused zone of a disc; determining a new rotating speed of the spindle motor, and driving the spindle motor at the new rotating speed; and linking recording zones to continue recording data at a new recording rate from the paused zone, when the rotating speed of the spindle motor is stable.

Abstract: The present invention relates to an optical drive capable of writing data to an optical carrier or disk, the optical drive having a laser driver device with an adjustable power level (VSL). The optical drive has a radiation source (4) capable of emitting a radiation beam (5) for writing data with a certain writing speed to an optical carrier and a laser driver device (LDD) comprising electronic circuitry means for providing a control current to the radiation source in response to a data signal (NRZ). The electronic circuitry means is supplied by an adjustable power supply (REG_SUP, 32) having a power level (VSL) that is adapted for being adjusted in response to the data writing speed to the optical carrier. The optical drive therefore has a reduced power dissipation compared with the hitherto known solutions. This results in an increased lifetime of the radiation source, e.g. the laser, and a reduced power usage.

Abstract: According to one embodiment, an apparatus which records a signal in a recording medium in which information is written by using a first laser having a first wavelength and from which information is read by using a second laser having a second wavelength longer than that of the first laser, a signal is recorded in the recording medium by using the first laser, and a control section reproduces the signal recorded with the first laser and measures a first amount that is used to calculate a target value for optimization of recording conditions, reproduces a signal recorded with the second laser and measures a second amount for optimization of a reproduction signal, compares the first amount with the second amount, and determines the first amount under the recording conditions where the second amount becomes optimum as a target value for optimization of the recording conditions.

Abstract: A recording control apparatus includes a waveform rectification section for receiving a digital signal generated from an analog signal representing information reproduced from an information recording medium, and rectifying a waveform of the digital signal; a maximum likelihood decoding section for performing maximum likelihood decoding of the digital signal having the waveform thereof rectified, and generating a binary signal representing a result of the maximum likelihood decoding; a reliability calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the digital signal having the waveform thereof rectified and the binary signal; and an adjusting section for adjusting a shape of a recording signal for recording the information on the information recording medium based on the calculated reliability.

Abstract: A method and apparatus demodulate pre-formatted information embedded in an optical recording medium. The demodulation includes (a) receiving a wobble signal representing data symbols frequency-modulated on a carrier frequency, (b) generating a phase delta signal representing a phase difference between the wobble signal and a corresponding locked signal having the carrier frequency, (c) first sampling the phase delta signal at a data sampling interval to produce first values, (d) second sampling the phase delta signal at each halfway of the data sampling interval to generate second values, (e) determining, based on a difference between two successive second values, if the first sampling is performed at timing corresponding to an end of each data symbol, and (e) adjusting sampling timing of the first sampling towards the timing corresponding to each end of the data symbols, if the sampling timing does not corresponds to the end of each data symbol.

Abstract: There is provided an optical disc having preformed thereon a spiral wobbled track as a grove and/or land along with data is to be recorded. The track is wobbled for a series of predetermined signal units each composed of an FSK information bit part based on a waveform resulted from FSK modulation of information bit and a singe-frequency part based on a waveform of a single frequency. The FSK modulation uses two different frequencies of which the one is the same as the single frequency and the other is different from the single frequency. These different frequencies are in such a relation that each of them has an even number of wobbles and an odd number of wobbles alternately in a predetermined cycle.

Abstract: To expand a capture range of a PLL circuit when a recording parameter optimal to a disc is decided when a PRML identification system is used. In an optical disc apparatus according to the present invention, the PLL circuit generates a reproduction clock signal based on a reproduction signal. A CPU determines whether a reproduction signal used when test data recorded on an optical disc is reproduced is locked in the PLL circuit or not. A spindle motor control circuit is controlled to change a speed of the disc to be increased when it is determined that the reproduction signal used when the test data is reproduced is not locked in the PLL circuit. The CPU decides a recording parameter and a write strategy correction value calculated on the basis of the reproduction signal used when the test data recorded on the predetermined area of the disc is reproduced.

Abstract: After the read head of a composite head reads sector data from a disk, a read circuit detects a sync mark in the sector data. The read circuit demodulates user data subsequent to the detected sync mark, and outputs it to a disk controller. A sequencer incorporated in the disk controller measures, as a read preamble data length, the data length of preamble data preceding to the detected sync mark. The sequencer determines the head gap length of the composite head from the data length of the preamble data of sector data to be written to the disk, a write path delay, the read preamble data length and a read path delay.

Abstract: A data reproduction device for sampling a signal reproduced from a recording medium based on a synchronization clock signal synchronized with the reproduced signal includes: an analog-to-digital conversion part converting the reproduced signal into a first digital signal based on a first clock signal; an interpolation part interpolating the first digital signal so that the first digital signal is equalized with a second digital signal sampled based on a second clock signal having a frequency n times the frequency of the first clock signal; an optimum phase detection part receiving the output of the interpolation part and detecting the phase error between the optimum point of the reproduced signal and the synchronization clock signal; a phase correction part correcting the phase of the reproduced signal based on the phase error; and an information data start detection part detecting the start of information data based on the phase error.

Abstract: An adaptive frequency detector used in a phase locked loop for detecting a frequency difference between an input signal and an output clock generated from an oscillator of the phase locked loop includes: a frequency comparator for generating an up signal or a down signal according to the frequency difference between the input signal and the output clock; and a pulse controller coupled to the frequency comparator for generating a charge signal based on the up signal or generating a discharge signal based on the down signal. The pulse controller dynamically adjusts the pulse width of the charge signal or the pulse width of the discharge signal.

Abstract: A combined signal Spc in which a pre-pit signal is superposed on a wobble signal is generated based on a radial push-pull signal Spp with a noise component having been removed therefrom. Based on the combined signal Spc, a wobble signal SWB with the phase ?0 not having time fluctuation and a pre-pit signal SPD are generated with the phases compared to each other, and then a phase adjustment signal SCNT corresponding to a phase difference ?e is generated. The phase differences ?e are stored, and an average value ?r thereof generated, the phase difference ?e is compared to the average value ?r, the phase ?0 is shifted according to only by the phase difference ?e only when the phase difference ?e is within the range of (?r±W), and then a wobble signal SWB with the phase ?1 synchronized to the pre-pit signal SPD is generated.

Abstract: A disk reproducing apparatus for reproducing a digital audio signal recorded on a DVD or CD has a PLL portion for outputting a synchronizing signal in synchronism with the digital audio signal. When the CD is reproduced at double speed or higher, the PLL portion increases again while seeking tracks, and restores the gain if a predetermined time has passed after the end of seek.

Abstract: An information writing/reading apparatus that cooperates with an information record medium including a ROM area and a RAM area, either the RAM area or the ROM area having in advance control information recorded thereon used to limit reading and/or writing of information, the information writing/reading apparatus including an optical pick-up unit for reading information stored on the information record medium; and a control unit for, based on the control information read by the optical pick-up unit, limiting reading and/or writing of information from/to the other area on which the control information is not recorded and outputting a signal which notifies of presence of the other area only out of the ROM area and the RAM area on the information record medium.

Abstract: A timing recovery method samples, equalizes and detects a signal reproduced from a recording medium and to output a detection signal, controls sampling positions based on a phase error between the equalized signal and the detection signal, and obtains likelihood information which is related to a bit having a probability of error which exceeds a predetermined value, based on the equalized signal. The control of the sampling positions is suppressed during a time which is based on the likelihood information.

Abstract: An optical disk apparatus includes a signal detection unit which detects a signal corresponding to a wobbling guide groove formed on an optical disk, a timing signal generating unit which generates first and second timing signals in accordance with an amplitude level of the signal detected, a photodetector which detects reflective light from the optical disk, and a wobble signal generating unit which outputs as a wobble signal a signal which is amplified with a low gain amount by the first timing signal in a case where an arithmetic signal, which is generated for the wobble signal on the basis of a signal detected by the photodetector, is at a high amplification level, and outputs as the wobble signal a signal which is amplified with a high gain amount by the second timing signal in a case where the arithmetic signal is at a low amplification level.

Abstract: A wobble signal reproducing device and method. The wobble signal reproducing device may include a computation unit for outputting a push-pull signal by use of a signal picked up by wobbling an optical disc; a wobble band pass filter (BPF) unit for applying band pass filtering to the push-pull signal based on a first control signal, applying low pass filtering to the band pass filtering-applied signal based on a second control signal, and outputting a wobble signal; a wobble phase locked loop (PLL) unit for generating a channel clock signal based on the wobble signal, wherein the first and second control signals correspond to the channel clock signal, the wobble BPF unit applies the band pass filtering at a center frequency varying based on the first control signal, and applies the low pass filtering at a cutoff frequency varying based on the second control signal.

Abstract: An information storage medium according to an aspect of this invention has an information storage area for storing information, and a wobbled track which is used to guide a light beam on the information storage area, and is wobbled in correspondence with a frequency, a phase of which is modulated at predetermined timings to reflect predetermined information. The wobbled track is formed so that an evaluation result based on the frequency characteristics of a squared reproduction signal obtained by squaring a reproduction signal corresponding to the wobbled track, obtained from the reflected light of a light beam with which the wobbled track is irradiated, meets a predetermined evaluation measure.

Abstract: For protecting the recording from shifting in the position, by conducting sync detection, correctly, from land pre pits, in an optical type recording disc, even if sync pattern errors, in more detail, synchronization is conducted on a recording circuit, with certainty, even if an even sync pattern erroneously changes into an odd sync pattern. When the even sync pattern is detected from an odd sync pattern detection window, a sync lock flag is turned into a condition of unlock. When the sync lock flag continues a lock condition for 16 sectors, the synchronization is carried out on a detection cycle counter and a recording cycle counter.