Abstract: A write clock generation circuit is provided that can detect wobble signal in high accuracy and can appropriately generate write clock with only small jitter even when the operation is switched from reproduction to recording. The wobble signal is obtained by changing stepwise the gain of a variable gain amp in the rear stage of a divided photo detector using a gain control circuit in a predetermined time period just after the beginning of recording. The write clock signal is generated using the above wobble signal. According to this arrangements, the change in wobble signal just before and after the beginning of recording can be reduced, and the gain change of a wobble signal amplitude regulation AGC is made slow. As a result, high frequency deviation of the wobble signal can be reduced even when the operation is switched from reproduction to recording, and the write clock with only small jitter can be generated.

Abstract: A method and apparatus for controlling the power of a laser diode, which can prevent fluctuation in the laser power of the laser diode at a record/playback area of an optical disc. The apparatus for controlling the power of the laser diode includes a controller which controls an automatic power control of the laser diode (APC controller), interposed between an up/down counter and a laser diode driver, the APC controller latching the output of the up/down counter in synchronism with a periodic synchronization signal, and outputting the latch result to the laser diode driver. Therefore, the power level of the laser diode can be periodically controlled according to subdivided control modes, so that the laser power level remains resilient to external noise, compared to a continuous control operation through the entire mode.

Abstract: A recording/reproducing apparatus and method are provided to record and reproduce data on and from a disk-shaped recording medium that has an address data area with embossed pits and a recording/reproducing area with a wobbling spiral groove. A wobble-signal processing circuit is used to extract a wobble signal from the signal the head obtains from the wobbling spiral groove and to provide the wobble signal to a PLL circuit to produce a sync signal therefrom. A pulse is produced at least during a wobble signal disturbance period occurring when switching between at least one of a recording and reproducing operation and provided to the PLL circuit in order to provide an unchanging sync signal during the wobble signal disturbance period to avoid the wobble disturbances from being carried over to the sync signal.

Abstract: A method and device are provided for jitter enhancement in an optical disc system. The optical disc system generates a signal that includes an effective component having a first slew rate, and a pre-pit component having a second slew rate larger than the first slew rate. The signal is fed to a slew rate control module having a predetermined slew rate that is larger than the first slew rate and smaller than the second slew rate. The slew rate control module outputs a component of the signal having a slew rate not larger than the predetermined slew rate, and suppresses a component of the information signal having a slew rate larger than the predetermined slew rate.

Abstract: It is a subject to provide an optical disc device which can speedily control generation of a data sync clock, when the position of data reading by an optical pickup shifts between a data unrecorded area and a data recorded area. An optical disc device comprises a first wobble cycle counter 702 for counting the cycle of a wobble reference signal S104 that is synchronized with a wobble signal S101 obtained from an optical disc, with a constant cycle clock S102; a second wobble cycle counter 703 for counting the cycle of the wobble reference signal S104 with a data sync clock S103; a count value comparator 704 for obtaining a difference between a count value outputted from the first wobble cycle counter 702 and a count value outputted from the second wobble cycle counter 703; and a comparison result judgement unit 710 for judging whether or not the value of a count value comparison result that is output from the count value comparator 704 is within a range of preset values.

Abstract: An optical disc having marks for dispersed addresses that can be easily detected with high precision. A dispersed address comprises synchronization marks, positive marks, and negative marks. Synchronization marks, positive marks, and negative marks are formed along a groove as partial discontinuities or partial modifications in the wobbled groove.

Abstract: On an optical disk medium according to the present invention, address information is recorded along a wobbling track groove 2. The track groove 2 is made up of a plurality of unit sections 22, 23. Each of these unit sections 22, 23 has side faces that are displaced periodically in a disk radial direction. This displacement oscillates at a single period in a tracking direction. However, the displacement pattern differs depending on “each bit of address information (subdivided information)” allocated to each of the unit sections 22, 23.

Abstract: An optical disc recording/reproducing apparatus includes: recording/reproducing means for recording/reproducing information by emitting a light beam onto a disc having a track which wobbles at a predetermined frequency; reflected light detection means for detecting the light beam reflected from the disc; wobble signal detection means for detecting a wobble amplitude signal which represents an amplitude of a signal generated from a component which is extracted from an output of the reflected light detection means and which wobbles at the predetermined frequency; and variation rate detection means for detecting dirt adhered on the disc based on a rate of a variation in the wobble amplitude signal, wherein the variation rate detection means detects the dirt based on the wobble amplitude signal before the recording/reproducing means records/reproduces the information.

Abstract: A signal processor used to process an analog read signal representing data stored on a magnetic disk allows for a faster read operation without requiring an increase in its circuit area or buffer memory space. The signal processor includes a decision feedback equalizer which selectively provides a feedback signal added to a read signal in reproducing data read from a storage medium. The signal processor also performs error correction. In performing error correction, the load of the error correcting process is detected and the processing speed is altered depending upon the detected load.

Abstract: An information recording medium is provided with a wobbled track, wherein at least a part of the track is subjected to wobbling based on a wobble signal in which at least a part of recording information is randomized. Each track is wobbled at a randomized frequency, so that a frequency of a wobbling signal obtained from the wobbled track is randomized. As a result, the influence of crosstalk between adjacent track is reduced.

Abstract: A method and related circuit for clock generation and recovery utilizes digital components exclusively. The method is used to generate a wobble clock and an absolute time in pre-groove (ATIP) clock for controlling the operation of an optical disk drive. The circuit includes a counter and a digital logic circuit and utilizes clock triggering processes.

Abstract: Linking gap detecting device and method in which a light beam is irradiated to an information recording track of an optical recording medium; a light detecting signal is generated by receiving reflected light of the light beam irradiated to the information recording track; a synchronous signal is detected from the light detecting signal; it is judged whether the existing interval of the synchronous signal lies outside a predetermined interval range or not; and the linking gap is detected on the basis of a result of the judgment.

Abstract: A method for generating a write clock of a constant angular velocity compact storage device and the device thereof. The compact storage device has a counter for generating a count number by a reference clock counting a wobble signal, and a phase detector for generating an adjustment value by comparing a phase shift between an ATIP synchronization signal and an encoded subcode frame synchronization signal. According to the count number and the adjustment value, a rectification value is found, and the rectification value and the reference clock is used for generating a reference write clock to modify the encoded subcode frame synchronization signal. If the phase shift between an ATIP synchronization signal and an encoded subcode frame synchronization signal is smaller than a predetermined value, the reference write clock is the write clock used by the compact storage device.

Abstract: A PLL circuit (24) reproduces a clock signal from a reproduction EFM signal of an optical disk (10). A phase error signal (pco) of the PLL circuit (24) is converted into an absolute value by an absolute value circuit (38), and is averaged for each subcode frame period by an accumulator (40). The recording beam power of a laser beam is determined on the basis of an output of the accumulator (40). A pulse-length discrimination circuit (26) discriminates the pulse length of the reproduction EFM signal. A specific-pulse-length phase-error-signal extracting circuit (42) extracts the phase error signal (pco) of a specific pulse length. The extracted phase error signals (pco) are averaged for the respective subcode frame periods by a accumulator (44). The time base of the corresponding pulse length of the recording EFM signal is corrected on the basis of the output of the accumulator (44).

Abstract: A mark detecting circuit that stably and reliably detects the marks for address information from an optical disk having tracks formed in a spiral shape and having waviness with a fixed period. In the land pre-pit signal extracting portion 12, by means of first bottom envelope circuit 32 with a high tracking speed, first bottom envelope signal Sbtm1 that represents at high sensitivity the bottom envelope of push-pull signal (SA+SB)?(SC+SD) is generated; and, by means of second bottom envelope circuit 34 with a low tracking speed, second bottom envelope signal Sbtm2 that represents at low sensitivity the bottom envelope waveform of push-pull signal (SA+SB)?(SC+SD) is generated. Then, with the signal, obtained by level shift treatment of said second bottom envelope signal Sbtm2 using offset circuit 36, used as threshold signal Sref, first bottom envelope signal Sbtm1 is converted to a binary form. And land pre-pit signal SLPP is extracted from push-pull signal (SA+SB)?(SC+SD).

Abstract: A sampling clock generator for BCA data decoding providing a sampling clock, which is proportional to the actual rotation speed of a disk. The sampling clock generator includes a frequency counter, a divider and a frequency divider. The frequency counter counts the number of pulses of a reference clock for each period of a rotation speed indicating signal of a spindle motor and generates a counting value. The divider divides the counting value by a predefined value and generates a divided value. The frequency divider is employed to generate the sampling clock. The frequency divider receives the reference clock and divides the frequency of the reference clock by the divided value to generate the sampling clock. The frequency divider also adjusts the phase of the sampling clock according to the BCA reproducing signal.

Abstract: In an optical disc, a wobble signal is to be detected by a simple configuration. In the optical disc, the address information, modulated onto a sinusoidal cannier signal by adding even harmonics signals to the sinusoidal carrier signal and by changing the polarity of the harmonics signals, is formed into the wobble signal. In detecting the wobble signal from the optical disc to demodulate the address information, in a method for detecting the wobble signal, an even harmonics signal and data clocks are generated, and the even harmonics signal so generated are multiplied with the reproduced wobble signal. The resulting product signal is integrated every data clock. The sign of the digital information is verified based on the integrated value at an end edge of the data clock.

Abstract: Described herewith is an optical disk manufacturing apparatus for reading recorded digital data from an optical disk, comprising an encryption unit (22, 23) for encrypting entered digital data according to a plurality of key information; an optical disk substrate manufacturing unit 2 for manufacturing an optical disk substrate 4 on which the encrypted digital data and key information are recorded in the form of physical form changes; a reflection film forming unit 41 for forming a reflection film on the optical disk substrate 4; and a key information recording unit 7 for recording key information on the optical disk substrate on which the reflection film is formed. The reflection factor of the optical disk is changed locally, thereby giving a jitter to the position information of each pit edge, and desired data is recorded additionally according to this jitter. Pits, etc.

Abstract: A semiconductor integrated circuit of this invention includes a synchronous detection circuit which is given a playback signal generated by reading both first data recorded before recording to an optical disk is interrupted and second data recorded after the interruption, detects synchronization of the playback signal, and outputs a playback sync signal, and a sync signal phase measurement unit which is given the playback signal and playback sync signal, and measures and outputs a phase difference between those components corresponding to the first and second data, which are contained in the playback sync signal.

Abstract: A recordable or rewritable optical disk device capable of reproducing a wobble signal accurately at a high S/N ratio to thereby get address information even at a time of high-speed recording is disclosed. An optical disk is formed with wobbled guide tracks, and the light reflected from the optical disk is picked up by an optical pickup unit, which supplies corresponding electric signal to a wobble signal reproducing section. In the wobble signal reproducing section, at a time of recording, the input signal is sampled not only during a period of reproducing power and also during a period of recording power, and the two sampled signals are added to reproduce a wobble signal. The sampling during the period of recording power may be carried out within a period where the quantity of reflected light is in a stable condition after a pit is formed on the optical disk.

Abstract: An optical disk drive capable of securing reliable reproduction of a wobble signal even under a constant angular velocity control of a recordable or rewritable optical disk is disclosed. The optical disk has a guide track wobbled to produce a constant frequency when the optical disk is driven under a constant linear velocity control. An optical pickup unit detects the light reflected from the optical disk, and a wobble signal reproducing section takes out a wobble signal. The wobble signal reproducing section has two band-pass filters; a first band-pass filter detects a center frequency of the wobble signal, which is caused to vary under the constant angular velocity control, and a second band-pass filter has a center frequency set to the detected center frequency whereby the wobble signal is extracted by the second band-pass filter. The extracted wobble signal is subsequently demodulated address information.

Abstract: Methods and systems for write compensation for optimizing the performance of a data storage or communication channel are disclosed. In one embodiment, a method comprises determining channel sensitivity to modifications in write signal parameters, detecting systematic errors in a read signal recovered from data written with a first set of write parameters, and adjusting the write signal parameters by an amount determined from the channel sensitivity such that the systematic errors are reduced when data are written with the adjusted write parameters.

Abstract: A clock adjustment apparatus for adjusting a phase of a clock signal based on a phase error thereof is provided in a data reproduction system which samples a readout signal from a recording medium in synchronism with the clock signal, and reproduces data in accordance with a Viterbi algorithm by using sampled values of the readout signal. The recording medium is recorded with the data modulated in accordance with a recording rule of a predetermined partial response characteristic. The clock adjustment apparatus includes a phase error calculation circuit which calculates the phase error of the clock signal based on the sampled values of the readout signal.

Abstract: A digital signal processor (1045) arithmetically determines a comparison level for comparing each signal component by determining a comparison level of comparators (1033 and 1034) for comparing a fine clock mark signal such that a larger weight is assigned to the comparison level of the signal component already compared. The comparators (1033 and 1034) compare the fine clock mark signal with reference to a level set on a peak side and a level set on a bottom side. When digital signal processor (1045) receives the comparison signal from one of the comparators (1033 and 1034) prior to the comparison signal sent from the other, the digital signal processor produces a fine clock mark detection signal FCMT based on the comparison signal sent from a comparator (1047). Thereby, the clock can be accurately produced based on the fine clock mark signal even when a signal component having a larger amplitude than that of the fine clock mark signal is detected.

Abstract: A calibration for a tracking error signal offset in a tracking servo system of an optical disk drive is presented. In some embodiments, the tracking error signal offset is adjusted for best servo function by, for example, adjusting the center of a tracking error signal when the tracking servo system is open to zero. In some embodiments, the tracking error signal offset is adjusted for best read function by, for example, adjusting the tracking error signal offset until the data jitter is minimized. Data jitter can be determined by reading data from the optical media and measuring the data error rate.

Abstract: An information playback apparatus is provided, which can provide a sound which sounds natural by controlling an abrupt change in a tempo in the case of random access playback. When a cue point is registered, audio data which makes seamless playback possible is stored into a cue point memory, and further, the beat density of a playback sound being played when the cue point is registered is measured and stored. When the cue point is specified to start random access playback later, a ratio of the beat density (?×DBPM) of a playback sound being played when the cue point is specified and the beat density (DBPMreg) stored in advance is found. Then, the random access playback is started after the beat density of a playback sound to be played after random access playback is started is corrected to be equal to the beat density when a start of the random access playback is specified.

Abstract: A method and related circuit for synchronizing a writing clock with a wobble clock of a compact disk (CD) drive. The CD drive is capable of rotating a CD that has a data track for recording data and a wobble track. The CD drive is capable of generating the wobble clock according to movement of the wobble track while the CD is rotating. Also the CD drive is capable of writing data on the data track according to the writing clock. The method includes adjusting the frequency of the writing clock so as to synchronize the writing clock and the wobble clock.

Abstract: An optical disc player having an optical pickup records and retrieves information on an optical disc while the optical disc is rotating. A rotation pulse is generated each time the optical disc rotates through a prescribed angle. A rotation frequency data representing a frequency of the rotation pulse is also generated. A servo processor performs servo processing for rotation control on the optical disc in accordance with the rotation frequency data. A sampling pulse generator performs computational processing on an input data signal to generate a sampling pulse. The sampling pulse generator also corrects the rotation frequency data based on a phase error between the sampling pulse and the rotation pulse to use a corrected rotation frequency data as the input data signal. Another servo processor performs servo processing for repetitive control on the optical pickup using the sampling pulse.

Abstract: A symbol length is evaluated on the basis of receiving a first-symbol length, and a phase error with respect to detection of a length of the first symbol before receiving a length of a second symbol following the first symbol. The process includes evaluating at least two random phase errors on the basis of the phase error received. A first random phase error is dependent on a deterministic phase error with respect to a first state corresponding to an absence of a corrected first-symbol length. A second random phase error is dependent on a deterministic phase error with respect to a second state corresponding to the corrected first-symbol length. The process includes retaining as an evaluated symbol length the first-symbol length received if the absolute value of the first random phase error reduces a condition of passing through the first state.

Abstract: A method for extracting information in a data signal stored on an optical disc. The information is stored in a plurality of channel bits. The method includes initializing a recovery period of a recovery clock to a predetermined value expressed in cycles of a first clock; sampling the data signal with the first clock; obtaining a leading edge time period expressed in cycles of the first clock of a pattern of bits from the sampled data in which at least a first bit has a first binary value, followed by a plurality of bits having a second binary value, and ending with a last bit having the first binary value, wherein the first and second binary values are not equal; updating the recovery period of the recovery clock to be equal to a new maximum period that is the leading edge time period divided by a division factor; extracting the information in the data signal based on the newest recovery period of the recovery clock; and detecting a predetermined code in the data signal.

Abstract: A data recording speed control apparatus and method for recording a data on an optical recording medium are disclosed.

Abstract: A method for playing a recording medium, in particular an optical storage disc, used to access titles more quickly. Stored in a run-in area of the recording medium is at least one address area that includes at least one address of a beginning of a title stored on the recording medium. The recording medium is played in a player having a read device. When the at least one address area is read out, the at least one address of a title beginning is converted to a start time of exactly one time unit and stored in a memory, with the start time corresponding approximately to the playing time of the recording medium up to the addressed title beginning. To position the read device at the beginning of the title, the track jump time is calculated directly from the corresponding start time stored in the memory.

Abstract: A circuit in an optical read/write device for protecting synchronizing patterns is proposed. The protection circuit utilizes a clock with constant frequency as a reference clock. The circuit for protecting synchronizing patterns of this present invention includes a SYNC detector, a frame period counter, a valid-frame-period judgment unit, a frame period memory, a window generator, a real SYNC judgment unit, a SYNC lock judgment unit, and a SYNC signal generator. The circuit counts the pulse number of a reference clock with constant frequency for each frame to get a constant frame period. Then, the circuit can correctly interpolate the lost frame SYNC signal immediately by counting the reference clock, when the disk is defected.

Abstract: A recording medium which has a zone or zones storing lookup tables comprising an edge shift value of leading and trailing recording pulses.

Abstract: In order to determine a laser emission waveform rule for a recording medium, such as a write-once optical disc, the present invention provides an information recording apparatus, an information recording method and an information recording system capable of determining optimal recording conditions by recording data for approximately one rotation, by reproducing the recorded area, by measuring a phase error for each combination of the length of a mark and the length of a space immediately before or after the mark and by changing an emission waveform rule on the basis of the measured phase error.

Abstract: Optimizing performance of physical disk drives in a disk array storage device with a plurality of logical volumes is accomplished by accumulating statistics over an interval to select two logical volumes for an exchange. After testing to determine any adverse effect of making that change, the exchange occurs to more evenly distribute the loading on individual physical disk storage devices. One set of statistics, seek time, is obtained by combining estimated disk access information and an interpolated seek time obtained from a template that stores characteristics seek times among different pairs of segments that define a physical disk device independently of a logical volume configuration.

Abstract: An optical medium storage device improves the usable life of re-writable optical storage mediums, such CD-RW, DVD+RW and DVD-RAM disks, by adjusting write parameters to compensate for time between an initial write on the optical storage medium and the current time, with adjusted write parameters fine-tuning signal-to-noise ratios and improving the number of reliable overwrites for the optical storage medium.

Abstract: A method of STW (servo track write) for improving the quality of the servo tracks by suppressing the misalignment of the write start position caused by the asynchronous continuous vibration of a disk drive is disclosed. The disk drive includes a spindle motor, a disk medium, a write/read head and a head moving mechanism for carrying out the sector servo operation. The STW method comprises the steps of detecting the continuous vibration asynchronous with the rotational frequency of the spindle motor, detecting the phase of the asynchronous continuous vibration detected, determining the write start sector of each servo track based on the detected phase of the asynchronous continuous vibration, determining the write start time of each servo track in accordance with the clock signal, and moving the head onto the servo track where the head positioning information is written, by the head moving mechanism and writing the information in the servo track based on the write start time.

Abstract: An optical reproducing apparatus in which reproduction of information is carried out by using an optical record carrier. In order to compensate a radial tilt between the surface of the record carrier and the objective lens, the objective lens is tilted. In the optical apparatus of the invention, the actuator of the radial displacement of the objective lens is used to also tilt the objective lens at the same time. A displacement of the objective lens in the radial direction by the actuator has a direct effect of tilting the objective lens. This is accomplished by a mechanical link between the radial displacement and the radial tilting. This has the advantage that there is no need for an extra tilt actuator to tilt the objective lens.

Abstract: A clock signal generating system using a wobble signal and a data reproducing apparatus, has a first block to detect a frequency error signal or a phase error signal from the RF signals on the recording medium and to output the detected frequency error signal or the detected phase error signal. A second block detects a wobble error signal from the wobble signals on the recording medium and outputs the detected wobble error signal. A clock generating unit generates a clock signal using the detected frequency error signal or the detected phase error signal of the second block when the RF signals have an error, and using the detected wobble error signal of the first block when the wobble signals have an error.

Abstract: An information recording/reproducing apparatus which is capable of recording information data even if prepits cannot be correctly read from a recording medium. Prepits are detected from a read signal retrieved from a recording medium to generate a prepit detection signal, and a block signal indicative of a recording timing is generated based on the prepit detection signal. In this event, when the prepit detection signal is normal, an information signal is recorded on the recording medium at a recording timing in accordance with the block signal. On the other hand, when the prepit detection signal is defective, the information signal is recorded on the recording medium at a recording timing in accordance with an auxiliary block signal having the same period as a block length, and a fixed phase.

Abstract: A method for compensating track offset in an optical disk drive is provided, which achieves complete compensation of the track offset and than reduces the compensation time for the track offset. (a) An optical disk with wobbled grooves is provided, the wobbled grooves being used for generating a wobbling signal with a wobbling period. (b) A beat-inducing signal is recorded on the disk. The period of the beat-inducing signal has a specific relationship with the wobbling period in such a way that a beat signal is induced by the beat-inducing signal and the wobbling signal. (c) A tracking-error signal is generated using a push-pull method by optically reading the wobbled grooves of the disk and the beat-inducing signal recorded on the disk. The tracking-error signal contains a beat signal induced by the beat-inducing signal and the wobbling signal. (d) Track offset is compensated based on the beat signal contained in the tracking-error signal.

Abstract: It is intended to provide a recording-medium operating device, a clock signal generating device for the recoding-medium operating device, and a method for generating a clock signal for the recoding-medium operating device that satisfy both operation with a wide-range data transfer rate using delay line provided with not so large number of stages and high correction accuracy and are advantageous in terms of low power consumption and suppression of noises. A reference clock group Ø0 through Øx different in phase are obtained by a PLL 1. One of the reference clock group is selected by a clock selector 2. A selected clock signal is inputted to a delay circuit 3 and one of output clocks from a delay line 31 is selected by a selector 3. With structure as such, selection by the clock selector 2 and the selector 3 is controlled so as to make phase difference between a clock signal and an RF signal minimum.

Abstract: An wobble signal detection circuit that is provided on an optical disk device and can detect a wobble signal having high accuracy and stability at least when recording information on an optical disk. This wobble signal detection circuit can be applied to plural types of optical recording media. With the wobble signal detection circuit, during a period for forming a space region, a first voltage signal provided from a first light receiving element is sampled and amplified to be a target voltage, a second voltage signal provided from a second light receiving element is sampled and amplified to be the target voltage. The difference between the two amplified signals are output as the wobble signal. The first and second light receiving elements are divided from each other in the direction tangential to a recording region on the optical recording medium.

Abstract: Crosstalk between tracks, land prepit leakage, and effects of recording power modulation can cause the wobble signal period to change irregularly, thereby producing jitter in the recording clock which is derived by frequency multiplying the wobble signal. This problem is resolved by a recording clock generating circuit having an arrangement to average the wobble signal period, a timer for generating a rectangular wave with substantially the same period as the average period, and a frequency multiplying PLL for multiplying the timer output. The period averaging arrangement in particular determines the approximate average period at every wobble period and reflects the phase difference between the wobble signal and the timer in the timer setting so as to improve recording clock stability.

Abstract: An estimation method produces a reproduction signal while reading from an information recording medium such as an optical disk, and uses an equalizer to produce an equalization signal. The method then synthesizes distribution levels of the equalization signal that range over distributions of (n+1) levels L0, L1, . . . , Ln (in which L0<L1 . . . <Ln and n>2), thereby creating a new distribution. The method then uses the standard deviation of the new distribution as an estimation reference value to estimate the quality of an information reproduction apparatus or the quality of the information recording medium. The quality estimate may be used to adjust a circuit in an information reproduction apparatus that reads the information recording medium.

Abstract: A position control method, which positions the relative position of an optical disk and an optical pickup to a position that provides the optimum value of the jitter value of the detection signal obtained by detecting the reflected light of an optical spot, has a jitter value acquisition procedure, which carries out multiple feed operations within the adjustment range of the relative position and obtains the jitter value at each feed position, an edge position setting procedure which sets as the edge positions relative positions that exceed a prescribed preset jitter threshold value, an optimum position computation procedure, which computes the optimum position that yields the optimum value for the jitter value, and an edge position setting procedure that sets the edge positions on the condition that there are at least two relative positions that yield a jitter value that exceeds the jitter threshold value.

Abstract: A recording apparatus includes a gate signal generator for generating a gate signal in accordance with the data signal; a pre-pit signal generator for generating a pre-pit signal from a signal read from the recording medium; a gate circuit for generating a pre-pit pulse train by allowing the pre-pit signal to pass therethrough in response to the gate signal; a pulse extractor for extracting pulses of predetermined waveform from the pre-pit pulse train; and a synchronization signal generator for generating a recording synchronization signal based on the pulses of predetermined waveform.

Abstract: Both of one audio information and another audio information are recorded on a same information record medium. An audio information reproducing apparatus is provided with: a detecting device for detecting said one audio information and said another audio information from the information record medium and also detecting a time period required for one beat of the detected another audio information; and an accumulating device for accumulating said one audio information detected from the information record medium to thereby continue reproducing and outputting said one audio information through the accumulating device. The audio information reproducing apparatus is also provided with a controlling device for controlling the detecting device to detect said another audio information and the time period required for one beat, within a time duration that the accumulated one audio information is being reproduced and outputted through the accumulating device.

Abstract: A recording medium is provided, which maximizes the recording capacity and simplifies the configuration of an information recording/reproducing apparatus including a pickup. In the medium, different types of wobbling signals are preformatted in each of the adjacent land and groove signal tracks. A same-phase wobbling signal provided by wobbling each side of the respective land and groove signal tracks in the same phase, and a different-phase wobbling signal provided by wobbling each side of the respective land and groove signal tracks in a different phase are used as the different types of wobbling signals. The physical positions of all the land and groove signal tracks are indicated by the same-phase wobbling signal.