Abstract: A method for using an optical disc apparatus to record data onto an optical disc in multiple write sessions. The optical disc apparatus includes a delay detection circuit for detecting gaps between data written to the optical disc in successive write sessions. The method includes writing a set of first data to the optical disc, searching for an ending location of the first data, writing a set of test data to the optical disc such that a beginning location of the test data is near the ending location of the first data, using the delay detection circuit to detect a gap between the first data and the test data, and writing a set of second data to the optical disc such that a beginning location of the second data is equal to the beginning location of the test data minus a value contained in the gap.

Abstract: A track servo control perform follow-up control of an optical beam to a track of an optical disk, and control the vibration of the optical beam due to the ID pit noise of the optical disk. The control system is comprised of a feedback control block for feedback-controlling the actuator by the track error signal from the actuator and the learning control block. Since the optical disk ID pit noise is periodic noise, the learning control block learns this, inputs the learning result to the feedback control system. The learning result is subtracted from the learning input, and the signal after subtraction is learned in order to converge the learning. Therefore even if the periodic ID pit noise is applied, this noise can be removed from the control loop and the vibration of the actuator due to periodic noise can be decreased, making a stable track follow-up operation possible.

Abstract: An information storage apparatus includes a mark reading section for reading a mark written on an information storage medium. A recording state changing section is provided for changing a recording state in an adjacent region situated next to a region from which the mark reading section fails to read a mark, so as to reduce cross talk caused by the adjacent region. The mark reading section reads the mark in the failed region again after the recording state changing section changes the recording state in the adjacent region.

Abstract: A method of and a circuit for providing a playback signal, which is compensated for time delay, from a photodetector having a plurality of outputs. A time difference between a first signal corresponding to a part of the outputs of the photodetector and a second signal corresponding to another part of the outputs of the photodetector is detected and one of the first and second signals is temporally shifted to compensate for a time delay between different outputs of the photodetector. The temporally shifted signal is summed with the other signal to provide a playback signal. Accordingly, the time delay between the outputs of the photodetector is compensated, thereby increasing the degree of modulation of the data playback signal. In addition, distortion or degradation of the signal is suppressed and occurrence of errors in the playback signal is minimized, thereby improving the reliability of the playback signal.

Abstract: An optical disk apparatus for driving an optical disk having formed therein sawtooth wobbles of +STW and −STW. A pickup receives a laser beam reflected from the optical disk and supplies a reproduced signal to a wobble signal processing section. The wobble signal processing section differentiates the reproduced signal and binarizes the differential signal with reference to a zero level. A pulse length of the binary signal achieved during a positive period is compared with that of the binary signal achieved during a negative period. When the pulse length achieved during the positive period is longer than that achieved during the negative period, the binary signal is determined to be a +STW. In contrast, when the pulse length achieved during the negative period is longer than that achieved during the positive period, the binary signal is determined to be a −STW, whereby a wobble signal is demodulated.

Abstract: The present invention is made to improve the conventional analog processing that is easily affected by variations in semiconductor processing. This invention provides a wobble signal processing apparatus that can reduce the circuit scale and the power consumption as well as improve the quality of signal processing. The wobble signal processing apparatus of the present invention digitally processes a part that has conventionally been processed by an analog system, and further a PRML circuit is provided to implement error detection, whereby the circuit scale and the power consumption is reduced. This improves the detection of a signal that is inputted to the wobble signal processing apparatus.

Abstract: A push-pull signal is detected 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. The detected push-pull signal is compared with a reference voltage thereby generating a land pre-pit detection signal. Of pulses included in the land pre-pit detection signal, those pulses having a small pulse width are regarded as noise pulses and removed thereby obtaining a corrected land pre-pit detection signal. The number of pulses included in the land pre-pit detection signal is counted, and the reference voltage is controlled in accordance with the counted number of pulses.

Abstract: A noise removal circuit of the present invention comprises a 180-degree odd multiple shifting section for outputting a 180-degree shifted signal that is phase-shifted from an input signal by an odd multiple of 180 degrees and difference output section for outputting a difference between the input signal and the 180-degree shifted signal. The noise removal circuit comprises a 360-degree shifting section for outputting a 360-degree shifted signal that is phase-shifted from an input signal by an integral multiple of 360 degrees and sum output section for outputting a sum of the input signal and the 360-degree shifted signal.

Abstract: When information is reproduced in an optical disk of high recording density or of low recording density, a main beam and sub-beams are emitted onto adjacent tracks. The main beam has a shape longer in a direction perpendicular to the tracks. When the optical disk of high recording density is reproduced, cross talk components from adjacent tracks included in signals reproduced from reflection light of the main beam are canceled by using signals reproduced from reflection lights of the sub-beams. When the optical disk of low recording density is reproduced, information is reproduced with a beam. Thus, two types of optical disks can be reproduced with a simple structure in a compatible way. In the cross talk canceling, discrimination marks formed along the tracks at constant distances are reproduced, and a time difference between the main beam and the sub-beams is corrected precisely by using track jump and detection of discrimination marks.

Abstract: A method and apparatus for measuring the crosstalk of an optical disc of an optical disc player adapted to reproduce signals recorded on the disc, in which there are concentrically or spirally formed continuous recorded signal strings or signal recording regions and in which there is provided a positioning aperture at the center of the disc substantially concentric with said recorded signal strings or signal recording regions. A light beam is wobbled at a predetermined amplitude in the direction along the radius of the optical disc. The wobbling period is set so as to be asynchronous with the period of the optical disc rotation. The ratio between the quantity of the traverse signal obtained by the optical pickup and the quantity of strays signals is measured as crosstalk.

Abstract: It is an object to provide a recorded information reproducing apparatus that allows to eliminate crosstalk from an adjacent track correctly, even from a recording medium having both a recorded area in which information data are recorded and an unrecorded area. In order to detect a crosstalk component from an adjacent track based on a correlation between a main read signal read from a main track and a sub read signal read from an adjacent track, the relative phase between the sub read signal and the main read signal is shifted.

Abstract: An input analog signal is digitized according to a level thereof by a digitizing circuit. A chattering component is removed from the digitized signal by a chattering removing circuit. A signal processing is performed according to the signal from which the chattering component is removed by the chattering removing circuit. In this course, the input analog signal is digitized together with the chattering component included therein by the digitizing circuit.

Abstract: Provided is an apparatus and a method of driving an optical disk, and more particularly, to an apparatus and a method of removing radial noise generated when an optical disk is reproduced. The apparatus removing noise in an optical recording medium driver provides a noise processor detecting an error signal from a high-frequency signal output by a pickup when the optical recording medium is reproduced, and removing noise included in the error signal and a second signal processor outputting a pickup motion signal moving the pickup by using the error signal from which noise is removed and which has been output from the noise processor. Through the apparatus and the method, it is possible to solve the problems of a focus drop in a focus servo, and a pickup lens which is confined to a right or left side in a tracking servo, by detecting and removing radial noise from the RF signals which are output from the optical disk.

Abstract: Disclosed is a recording apparatus comprising: an audio level detecting unit, for detecting an audio level L indicating the level of sounds collected by a microphone unit and for notifying a control unit of the detected audio level L; and a control unit for changing the rotational speed of a spindle motor in accordance with the audio level L. With this configuration, noise generated during recording can be reduced and the high-quality recording of sounds can be performed.

Abstract: A method of reproducing information by scanning information marks, disposed with a predetermined mark pitch therebetween and recorded on tracks inside a predetermined information recording region, by an optical spot. The method includes detecting the size of the optical change resulting from the information mark, calculating a plurality of equalization coefficients used for an equalization processing for the size of the optical change detected for each of the information marks, and reducing the inter-symbol interference on the basis of the equalization coefficients by the equalization processing. The equalization coefficient used for the equalization processing of the size of the optical change by a first information mark is greater than said equalization coefficient used for the equalization processing of the size of said optical change by a second information mark which is longer than the first information mark.

Abstract: An optical disc is irradiated with a main beam and a pair of side beams, and respected reflected beams of light are detected by a main detector and a pair of side detectors. A first push-pull signal is generated which includes wobble components obtained by a detection signal from the main detector, and second and third push-pull signals are generated using detection signals from the pair of side detectors. The second and third push-pull signals are added by an adder to generate crosstalk components included in the first push-pull signal, and wobble information of the recording track is generated and output using signals obtained by canceling the crosstalk components in the first push-pull signal including wobble signal components in the recording track.

Abstract: For reproducing data, a first read signal from a main track is filtered and second read signals from tracks adjacent to the main track are filtered. A cross-modulation component included in a third read signal from the main track is removed by calculating an estimated value of cross-modulation for the main track by multiplying the filtered first read signal by the filtered second read signals and by subtracting the estimated value from the third read signal. A crosstalk component caused by the adjacent tracks included in a fourth read signal from the main track is removed by obtaining the crosstalk component by filtering the second read signals and by subtracting the crosstalk component from the fourth read signal.

Abstract: Crosstalk cancellation is realized more accurately than ever by considering both magnitude and a phase difference of a crosstalk signal from a recording track adjoining a target track, in comparison with magnitude and a phase of a desired signal from the target track, which is implemented by providing a crosstalk amount detection means, a phase difference measurement means, and a crosstalk component generation means that generates a crosstalk component to be subtracted from a signal obtained by an optical scanning that includes the desired signal and the crosstalk.

Abstract: Methods and apparatus are provided for reducing cross-talk and jitter caused by track offsets in multi-beam optical disks. The method and apparatus involve using split detectors and cross-talk cancellation algorithms in the multi-element photodetector of the multi-beam optical disks. The cross-talk cancellation algorithms are applied according to the value of the track offset as a function of the track pitch.

Abstract: An information reproducing apparatus for reproducing information of information marks by scanning information marks recorded on tracks inside a predetermined information recording region by an optical spot, the apparatus includes a driving device, an optical head, a head driving device, a laser driving device, an automatic gain control circuit, a non-linear equalization circuit, a phase locked loop circuit, a data demodulation circuit, and a control circuit.

Abstract: An information reproducing apparatus includes: a light emitting device that emits a light beam to the recording medium; a detecting device that detects the light beam reflected by the recording medium, and that generates a detection signal including a first component and a second component which have different middle levels; a sampling device that samples the first component and the second component included in the generated detection signal; an extraction device that extracts a first sampling value closest to the middle level of the first component from the first component, and that extracts a second sampling value closest to the middle level of the second component from the second component; a signal generation device that generates a first middle level signal by using the extracted first sampling value, and that generates a second middle level signal by using the extracted second sampling value; a compensation device that shifts the first component and the second component such that both the first middle l

Abstract: An optical disc apparatus for recording test data on a predetermined area of an optical disc under varied recording powers to determine an optimum recording power based on the quality of a signal obtained by reproducing the recorded test data. The test data is recorded under adverse recording conditions so as to evaluate the amount of change in quality of the reproduction signal. In order to create adverse recording conditions, the optical disc is tilted or the laser is defocused. A recording power for which the change in signal quality due to the deteriorated recording conditions is sufficiently small is determined as an optimum recording power capable of providing adequate recording margin.

Abstract: An optical disk provided with a land region and a groove region that are formed on a substrate, the land region and groove region being used as a recording track that is the medium of the recording/playback of information signal, and a pre-pit region that is formed at the boundary part of neighboring land region and groove region and is disposed every other boundary part, the pre-pit region including specific information. Characteristically, the specific information's in neighboring pre-pit regions are not aligned in the radius direction of the optical disk.

Abstract: There is disclosed a crosstalk removal apparatus in which a main track, one adjacent track, and the other adjacent track in a disk with the tracks formed therein are irradiated with light beams at predetermined intervals in a tangent direction by a pickup. A CTC unit uses delay amounts of respective sample value series corresponding to a reproduction signal of the main track and those of the adjacent tracks to correct delays, and outputs a CTC output signal from which a crosstalk component is removed. A wobble signal detector detects wobble signals of the respective tracks based on a push-pull output of the disk, and a delay circuit controller obtains optimum delay amounts based on a phase relation of the respective wobble signals and sets the delay amounts in the CTC unit.

Abstract: An information reproducing apparatus method includes the steps of radiating an optical spots to scan information marks recorded on tracks inside a predetermined information recording region, detecting an optical change of the information marks by this scanning operation, executing a signal processing for the reproducing signal so as to reduce inter-symbol interference of an interference amount that varies for each of the information marks, and reproducing the information corresponding to the information mark. The magnitude of the optical change due to the information mark is thereby detected, and a plurality of equalization coefficients used for an equalization processing are calculated for the magnitude of the optical change detected for each information mark. The inter-symbol interference is reduced on the basis of these equalization coefficients.

Abstract: An optical disk apparatus capable of adjusting a focus servo and the like by precisely detecting a jitter amount. Light reflected from an optical disk is converted into an RF signal in an optical pickup and amplified by an RF amplifier before being supplied to an equalizer. The boost amount of the equalizer is set to zero during adjustment and set to a predetermined finite value (e.g., +20 dB) during normal recording and reproducing. By first setting the boost amount to zero, the delay characteristics of the RF signal from 3T to 11T are flattened such that an accurate jitter amount can be determined based on the integrated value of the phase differences of 3T to 11T, thereby allowing the optical pickup to be adjusted so as to minimize the jitter amount.

Abstract: There are disclosed an information reproduction apparatus, signal processing apparatus, and information reproduction method which can remove a crosstalk to a wobble signal, particularly a crosstalk attributed to an RF signal. The information reproduction apparatus for reading information of an optical recording medium includes a detector for outputting a difference between individual output signals optically obtained by a pair of detectors for reading the information of a first track, a detector for reading RF information of a second track adjacent to the first track, a demodulator for demodulating a detection signal outputted from the detector, and a crosstalk canceller which uses the detection signal outputted from the detector to cancel the crosstalk arising from the RF information of the track included in the detection signal outputted from the detector.

Abstract: A pick up irradiates light beams at specified intervals in the tangential direction of the main track to be reproduced and both of adjacent tracks on a disk 10 on which tracks are formed. A CTC unit 15 uses the delay amount &Dgr;d of the respective sample-value series corresponding to the reproduction signal RFm from the main track and reproduction signals RF1, RF2 from both adjacent tracks to correct the delay, then outputs a CTC output signal from which the cross-talk component has been removed. In addition, when adjusting the delay, the CPU 17 applies a disturbance to the control signal for the actuator of the servo-control unit 18 and changes the delay amount &Dgr;d within a specified range of change. At this time, the CPU 17 sets the delay amount &Dgr;d, which minimizes the jitter value found by the jitter detection unit 16 according to the CTC output signal, for the CTC unit 15.

Abstract: This invention provides a method of acquisition of binary information that has been stored physically in a periodic storage medium. The method, referred to as matrix-method deconvolution (MMD), is useful for use with optical storage media using an optical addressing system that reads and writes binary information in a periodic array of nano-particles. With this MMD method, the density of existing memory systems can be boosted to between 10 and 100 Terabytes of data per cubic centimeter. This matrix-method deconvolution method compensates for the effects of the optical addressing system's point spread function. Prior knowledge of a system's point spread function and inter memory-center spacing is used.

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: In an apparatus for reproducing recorded data, a crosstalk signal is generated by converting adjacent data recorded on an adjacent track into a waveform of said reproduction signal and the crostalk signal is deducted from the reproduction signal. Then, the reproduction signal in which the crosstalk signal is eliminated is decoded in accordance with the predetermined algorithm and reproduced.

Abstract: An information playback apparatus of the present invention is provided with: a first detecting unit for supplying a difference between respective output signals optically obtained by a pair of detectors for reading the information of the first track; a second detecting unit for supplying a difference between respective output signals optically obtained by a pair of detectors for reading the information of the second track adjacent to the first track; a first demodulating unit for demodulating a detected signal supplied from the first detecting unit, a second demodulating unit for demodulating a detected signal supplied from the second detecting unit. A coefficient controlling unit extracts the crosstalk caused by the second track, which is included in a demodulation signal obtained by the first demodulating unit, from the same signal and controls a coefficient based on the extracted crosstalk, and cancels the crosstalk by the calculated coefficient.

Abstract: An automatic gain controller (AGC) for preventing peaking in an optical disc reproducing system includes a capacitor for being charged to a voltage corresponding to a control current as a control voltage; an amplifier for inputting the optical disc reproducing signal as an input signal, amplifying the input signal by a gain corresponding to the control voltage, and generating the amplified input signal as the output signal; a peak detector for detecting a peak voltage in the output signal; a gm amplifier for converting a peak voltage detected by the peak detector into current and generating the converted current as the control current; and a peaking controller for preventing the capacitor from being charged by the control current in a defect section in the input signal, in response to a peaking control signal, and for maintaining a control voltage in the defect section to be the same as the prior to the defect section.

Abstract: In a crosstalk canceling system for use in an optical disk signal reproducing apparatus, rough delay units roughly adjust a delay amount of reproduction signals and fine delay units finely adjust a delay amount with high precision, and a delay amount control unit controls the delay amounts of the rough and fine delay units so that the jitter of the reproduction signal is minimized.

Abstract: A phase compensation method uses a phase plate to compensate for an optical phase of a reproduced signal in a reproducing optical system which is provided with respect to the reproduced signal from an optical recording medium. The position of the phase plate is controlled within a predetermined variable range depending on a type of the optical recording medium, so that a CNR of a reproduced signal becomes a maximum or, a DC fluctuation of the reproduced signal becomes a minimum or, a crosstalk level from adjacent tracks becomes a minimum.

Abstract: An optical disc drive usable with discs to which data is continuously recorded and discs having a sector format can quickly resume playback signal output after passing imperfection causing potential reading errors, and plays disc with few read errors. A detection signal generator detects DC level fluctuation in the playback signal read from the disc and generates a detection signal tracking the DC level fluctuation. A selector selects a detection signal or a null signal without valid polarity based on the detection signal generated by the detection signal generator and input to the selector. A clamping unit performs a clamping process to suppress DC level fluctuation in the playback signal based on the detection signal when the selection unit selects the detection signal, and does not perform the clamping process when the selection unit selects the null signal. A signal processor performs specific signal processes based on clamping unit output.

Abstract: An aberration correcting element includes a first aberration correction element movable along the optical axis of the light beam for correcting the aberration of the light beam; a driver for positioning the first aberration correction element along the optical axis in response to a drive control signal; a second aberration correction element having a plurality of phase adjustment portions each generating an amount of phase change in the light beam, the amount corresponding to an adjustment signal; a phase adjuster for supplying the adjustment signal to the respective adjustment portions in response to a phase control signal; a light receiver for receiving the light beam reflected from the recording medium to generate a light-receiving signal; and a controller for generating the drive control signal and the phase control signal based on the light-receiving signal.

Abstract: Apparatus and method for detecting zero-crossings and correcting asymmetry of an RF signal. The RF signal is first converted into a digital signal having a plurality of samples. Zero-crossings detection is achieved by calculating the differences between neighboring samples, and by determining whether the differences exceed a pre-determined threshold value. Zero-crossings are also detected by comparing the differences to a pre-determined negative threshold value when the differences are negative. If a zero-crossing sample, a sum of the data values of the neighboring samples is used to generate an asymmetry offset value.

Abstract: A first multiplier 251 multiplies a reproduced RF signal rf(t) by a DC component of an APC monitoring output signal m(t), which component is an output signal from an LPF 252, and then supplies a signal resulting from the multiplication to an arithmetic unit 255. A second multiplier 254 multiplies the reproduced RF signal rf(t) by a laser noise component of the APC monitoring output signal m(t), which component is an output signal from an HPF 253, and then supplies a signal resulting from the multiplication to the arithmetic unit 255. The arithmetic unit 255 subtracts the signal from the multiplier 254 from the signal from the multiplier 251 to thereby remove both an additive noise component and a modulated noise component of laser noise.

Abstract: An apparatus (22) for reducing noise in a tracking error signal receives input signals from an array (5) of photodetectors, each input signal indicating the amount of laser light incident on the corresponding photodetector reflected from an optical disc. The input signals from diagonal pairs of photodetectors are summed and then filtered and digitized to produce a pair of digital input signals. A signal difference generator (20) produces first and second difference signals when either the first or the second digital input signals are received. The first and second difference signals are received by a programmable timing element having a user programmable device (41) and a signal limiting device (32, 33, 34, 35) for limiting the duration of the first or second difference signals provided at respective first or second outputs of the programmable timing element to a user programmable maximum value.

Abstract: Disclosed is a tilt controlling method and apparatus in which an RE signal track at a point where an RF signal is the maximum or an RE signal track at a point where a jitter is the minimum is detected as a tilt control signal to induct a DC component according to the disk shape and an AC component according to the surface vibration of the disk. Further, the fact is used that an RF envelope has the maximum value when the disk is parallel to an object lens or there is no tilt. Thus, in a tilt initialization step, a tilt track as the RF Max. is obtained for one rotation and the central potential of this track is set as a tilt control reference voltage, and when the RF envelope becomes a phase corresponding to a condition of a controller or a differential value of the RF envelope in the tilt window signal becomes a desired phase, tilt control is started so that the RF envelope always has the maximum value.

Abstract: An optical storage unit which uses a light beam to record information on and/or reproduce information from a recording medium. The recording medium is provided with at least one land and at least one groove, and information is recorded in plural sectors in each of the land(s) and groove(s). The optical storage unit includes an optical phase adjuster for adjusting a phase of a polarization component of the light beam reflected from the recording medium based on a track type determination of a target address. An optical pickup is provided for reproducing information recorded on the recording medium using the phase-adjusted polarization component of the light beam.

Abstract: There are provided an information storage apparatus and an information reproducing method capable of reading a mark without being disturbed by cross talk even if a track pitch is narrow.

Abstract: A recording method includes a reading step of detecting a reflection light from a recording layer to which a recording is to be made and converting the detected light into a read signal; a detecting step of detecting a position of a preformatted area of a recording layer which the optical beam transmits therethrough other than the recording layer to which a recording is to be made; and a correcting step of correcting intensity of an irradiation light beam or a reproduced signal on the basis of the read signal and the preformatted area position. An apparatus for carrying out the recording method is also provided.

Abstract: A method is disclosed for compensating for intersymbol interference on an optical disc. The method includes measuring an intersymbol linear transfer function. The intersymbol linear transfer function substantially describes a linear portion of the effect of intersymbol interference on an optically detected read signal from an optical disc. A partial response target frequency response is divided by the intersymbol linear transfer function to obtain a linear equalization filter response. A read signal from the optical disc is convolved with the linear equalization filter response. This results in the read signal being equalized and containing a controlled partial-response target intersymbol interference. There is also disclosed a method of compensating utilizing a decision feedback equalizer where the target frequency response is either a partial-response or a zero-forcing response.

Abstract: A tracking control method and a tracking control apparatus in a recorded information reproducing apparatus which can execure an accurate tracking control even if recording tracks formed on a recording disk have a narrow track pitch. A tracking offset component is detected based on a balance between crosstalk amounts from the recording tracks adjacent to both sides of the recording track serving as a reading target and is subtracted from a tracking error signal, thereby performing a tracking offset correction.

Abstract: An optical disc is irradiated with a main beam and a pair of side beams, and respected reflected beams of light are detected by a main detector and a pair of side detectors. A first push-pull signal is generated which includes wobble components obtained by a detection signal from the main detector, and second and third push-pull signals are generated using detection signals from the pair of side detectors. The second and third push-pull signals are added by an adder to generate crosstalk components included in the first push-pull signal, and wobble information of the recording track is generated and output using signals obtained by canceling the crosstalk components in the first push-pull signal including wobble signal components in the recording track.

Abstract: An optical disc drive usable with discs to which data is continuously recorded and discs having a sector format can quickly resume playback signal output after passing imperfection causing potential reading errors, and plays disc with few read errors. A detection signal generator detects DC level fluctuation in the playback signal read from the disc and generates a detection signal tracking the DC level fluctuation. A selector selects a detection signal or a null signal without valid polarity based on the detection signal generated by the detection signal generator and input to the selector. A clamping unit performs a clamping process to suppress DC level fluctuation in the playback signal based on the detection signal when the selection unit selects the detection signal, and does not perform the clamping process when the selection unit selects the null signal. A signal processor performs specific signal processes based on clamping unit output.

Abstract: A writable optical disc has an information writing track, and a guiding track for introducing a laser beam to the information writing track. The guiding track has prepit information recorded thereon, the prepit information including at least address information of the optical disc. The prepit information is recorded on the guiding track at a position where interference of adjacent guiding tracks with the prepit information is prevented. The information writing track is a groove track, and the guiding track is a land track.

Abstract: An information reproducing apparatus for reproducing digital record information recorded on an information record medium is provided with: a generating device for reading out the digital record information from the information record medium to thereby output a reproduction signal; a sampling device for sampling the reproduction signal by using a sampling clock signal having a predetermined sampling frequency to thereby output the sampled reproduction signal; a detection device for detecting a direct current level of the sampled reproduction signal by extracting a zero-cross sample value, which is a sample value contained in the sampled reproduction signal and is the closest sample value to a zero level in the sampled reproduction signal, from the sampled reproduction signal; a correcting device for correcting the sampled reproduction signal by subtracting the detected direct current level from each sample value of the sampled reproduction signal to thereby output the corrected sampled reproduction signal; and