Abstract: The invention provides for a method, and related apparatus, of producing a Land Pre-Pit signal during playback of an optical disc and including the steps of obtaining an output signal from an optical detector and from which the Land Pre-Pit signal is to be derived, scaling the said output signal responsive to a determined amplitude of a high frequency crosstalk signal arising during reading of the disc and in a manner so as to increase the said output signal when the Land Pre-Pit identified as corresponding to a mark on the disc, and so as to decrease the output signal when the Land Pre-Pit is identified as corresponding to a space on the disc.

Abstract: A servo control system and method is provided, comprising: a controller outputting a parameter control signal; a device having a parameter controlled based on the parameter control signal; a sensing circuit sensing the parameter of the device and generating a parameter error signal; a sinusoidal signal generator generating a sinusoidal signal; and a adder combining the parameter error signal and the sinusoidal signal, wherein the controller includes a servo equalizer that equalizes the added parameter error signal and the sinusoidal signal to output an equalized parameter control signal to adjust the parameter.

Abstract: An optical pickup includes: light collecting element for selectively collecting main and sub beams emitted toward an optical disc formed by layering at least first and second recording layers, onto one of first and second recording layers; main and sub light reception elements receiving the main and sub light from the main and sub beams collected from the optical disc and outputting main and sub light signals; tracking error signal generator for generating a tracking error signal according to the sub light signal; noise component calculator for calculating a noise component generated by interference between the sub light and an invalid light attributed to at least one of the applied main and sub beams and received together with the sub light and the sub light from the other of the first and the second recording layer; and noise remover for removing the calculated noise component from the tracking error signal.

Abstract: The present techniques provide methods and systems for reading and processing a data signal read from an optical data disc. In embodiments, an optical reader system may read data bits from a data ring in the disc. The data rings may be concentric, and a beginning of a sequence of data on the data ring may be in substantially the same position as an ending of the sequence. The reader may identify a data ring and begin the read process on the targeted data ring, and may end the read process when the reader reaches the starting point. The data sequence read from the data ring may be decoded to form a bit stream, which may be provided to various output devices. A circular trellis formed from the bit stream may enable the reading of a targeted data sequence without additional tail bits to improve data transmission efficiency.

Abstract: In a method of and an apparatus for creating a reproduced wobble signal by subtracting an estimated crosstalk signal, expressed by a sine waveform having a frequency approximately equal to the meandering frequency of grooves, from an original wobble signal and recording or reproducing an information pattern at a predetermined position of an optical disc, a carrier signal, which is caused to correspond to the meandering of the groove by being subjected to phase synchronization, is assumed based on the reproduced wobble signal, a crosstalk remaining component is estimated from the amplitude and phase of the region, which meanders in approximately the same phase as the estimated carrier signal in the reproduced wobble signal, and from the amplitude and phase of the region which meanders according to a signal different from the estimated carrier signal, and the estimated crosstalk is updated to cancel the remaining component.

Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

Abstract: According to one embodiment, a frequency characteristic adjusting circuit includes a cutoff range adjusting module and a control signal inputting module. The cutoff range adjusting module is connected to an AC coupling circuit capacitively coupled with a signal transmission path, and allows an output signal from the AC coupling circuit to pass through such that a low cutoff range in the frequency characteristic of the AC coupling circuit varies. The control signal inputting module receives a control signal to control a zero-point frequency based on a numerator polynomial of a transfer function of the cutoff range adjusting module and a pole frequency based on a denominator polynomial of the transfer function. The numerator polynomial is equalized to a denominator polynomial of a transfer function of the AC coupling circuit by the control signal. A cutoff frequency is determined by the pole frequency according to the control signal.

Abstract: An optical disc reproducing apparatus has a function of setting a cutoff frequency and a boost amount of a read out signal from an optical disc and performing equalizer adjustment, and includes a system controller for searching for an optimal jitter value by simultaneously changing a cutoff frequency and a boost amount to thereby set positions of jitter measuring points determined on a coordinate plane whose abscissas represent cutoff frequencies and whose ordinates represent boost amounts, and by moving the measuring points.

Abstract: A disk device includes: a rotating unit for rotating the optical disk; an optical pick-up for reading the information data recorded on the optical disk; a moving unit for moving the optical pick-up; a focus control unit for leading the focus of the optical pick-up; a tracking control unit for leading the tracking of the optical pick-up; and an adjusting unit for changing the setting value of an equalizer to adjust the equalizer, wherein: when the optical disk is loaded on the disk device, the optical pick-up is moved to the innermost periphery of the optical disk, the optical disk is rotated, the focus and the tracking are led, and the operation of the optical pick-up is raised; and the setting value of the equalizer is changed to adjust the equalizer at a position where the operation of the optical pick-up is raised.

Abstract: This signal detection method detects an output signal indicating data information contained at least in two sideband waves from an input signal having a carrier and at least two sideband waves accompanying the carrier. The method includes a cut off step for cutting off a sideband wave positioned at the high frequency side or the low frequency side as compared to the carrier from the at least two sideband waves and a square detection step for outputting an output signal by performing square detection of an input signal having one of the sideband waves which has been cut off.

Abstract: An information recording device includes a buffer memory, a buffer management unit and a phase adjusting unit. The buffer memory temporarily stores data to be written in a recording medium. The buffer management unit starts writing the data in the recording medium if a size of the data stored in the buffer memory exceeds a first predetermined size, and suspends writing the data in the recording medium if the size of the data stored in the buffer memory becomes less than a second predetermined size. Additionally, the phase adjusting unit starts adjusting a phase error between a signal synchronous to the data and a signal synchronous to a location on the recording medium when the buffer management unit starts writing the data in the recording medium, and finishes adjusting the phase error so that the phase error becomes substantially zero before the buffer management unit suspends writing the data in the recording medium.

Abstract: By decoding a formatted 1-77PP signal 22 outputted from a BD-ROM formatter 20 at a high speed, comparing it with original data 34 in a comparator unit 30 and checking authenticity of data from the BD-ROM formatter 20 in real time, it is possible to carry out a check of data outputted from the RD-ROM formatter in real time when exposing the 1-77PP data from the BD-ROM formatter.

Abstract: According to the present invention, when an apparatus performs reproduction from an optical disc of a format not compatible to the apparatus, the apparatus is prevented from obtaining an incorrect address and thus causing a malfunction. A recording method according to the present invention performs first conversion of bit-inverting m number (1?m<n; m an integer) of symbols at prescribed positions of a code word coded using an error correction code by a Reed-Solomon code and including symbol C(i) [i=C=0, 1, 2, . . . n; n is an integer] to generate conversion information; and records the conversion information on a first recording medium.

Abstract: After a playback RF signal 3 detected from an optical disc medium 1 is waveform-shaped, it is converted into a digital RF signal 6 with a sampling clock 8 having a cycle twice as long as a channel clock. Thereafter, a first offset correction circuit 9 corrects an offset fluctuation in a high frequency band, and a digital adaptive equalizer 23 performs adaptive equalization, and then a second offset correction circuit 27 corrects an offset component that remains after the offset correction by the first offset correction circuit 9, thereby demodulating a digital binary signal 37. Therefore, even when high-speed playback is carried out and an asymmetry depending on the recording quality is large, a reduction in power consumption can be realized while maintaining high-performance playback. Consequently, it is possible to provide an optical disc playback apparatus which can realize sufficient playback performance at low power consumption.

Abstract: A disc playback apparatus is configured to reproduce information by demodulating and decoding a radio-frequency signal obtained by receiving reflected light of a beam applied to a recording surface of a removable disc when the disc is loaded in the disc playback apparatus. The apparatus includes a disc format determining unit adapted to determine the format of the loaded disc, a high-frequency compensation unit adapted to compensate for a high-frequency component of the radio-frequency signal, a low-frequency compensation unit adapted to compensate for a low-frequency component of the radio-frequency signal, and a control unit adapted to determine which of the high-frequency compensation unit or the low-frequency compensation unit is to be used to compensate for a frequency characteristic of the radio-frequency signal based on the determined disc format.

Abstract: A method for generating a feedback signal in optical disc drives is disclosed. Firstly RF signal is generated by a pickup head and coupled to a converter to generate a digital signal. Then a detector generates a plurality of pseudo-jitter according to the digital signal. Thereafter a calculator receives the said pseudo-jitter and calculates for outputting a feedback signal to the pickup head.

Abstract: An information reproduction apparatus and method according to the present invention are provided so as to solve the problem that signal quality is degraded in a normal signal part when always performing a correction of a transient in reproducing information recorded in a medium, and the sag cancellation controller (103) detects whether the pickup output signal (S101) is normal or abnormal, and the sag cancellation part (104) performs a correction of a transient only during a period when the pickup output signal (S101) is detected as abnormal, thereby preventing degradation of signal quality, which is caused by performing a correction of a transient on a normal signal part, and an appropriate correction of a transient can be performed on an abnormal signal part, thereby enabling a stable reproduced signal (S104) to be obtained.

Abstract: A mark representing information of a multivalued level is recorded in each of cells arranged in a recording medium. Upon reproducing the multivalued level from a reproduction signal of the recording medium, the multivalued level of a present cell is judged by referring to a judged multivalued level of a preceding cell preceding the present cell or an ensuing cell ensuing the present cell, or by referring to the judged multivalued levels of both the preceding cell and the ensuing cell.

Abstract: An object of the present invention is to appropriately cope with a tears type mark occurring in, for example, an organic dye write-once disk. A playback signal distortion compensation method is a method for compensating a distortion in a playback signal of data recorded in an optical disk, and includes the steps of: specifying part of a playback signal of a mark having a length equal to or larger than a predetermined length; and, if a specific amplitude level value that will not appear in an ideal signal is detected in the specified part of the playback signal at specific sampling timing, setting the amplitude level values detected at the specific sampling timing and predetermined sampling timing alike to predetermined level values based on the ideal signal. Owing to the compensation of the amplitude levels, a transition of amplitude level values in the signal can be approached to a transition thereof in the ideal signal. Consequently, degradation of a bit error rate can be hindered.

Abstract: A unit to remove crosstalk in a multi-layered disk, an optical pickup including the unit, and an optical recording and/or reproducing apparatus including the optical pickup, of which the optical pickup includes: a light source; an optical path changer to change the path of light emitted from the light source; a unit to remove crosstalk; an objective lens to focus incident light on a disk; and a photodetector detecting light reflected by the disk such that the unit to remove crosstalk separates light reflected by a target recording layer of the disk from light reflected by adjacent recording layers so that the light reflected by the target recording layer and the light reflected by the adjacent recording layers do not overlap on the photodetector.

Abstract: The present invention is directed to a recording/reproducing apparatus having a Read After Write function which simultaneously performs recording operation and reproduction operation, and is such that, in a reproducing system (120) of a tape streamer (100) which performs Read After Write operation for signals through a magnetic tape (105), the apparatus serves to distribute reproduction signals obtained from the magnetic tape by a first data distribution switch (133) to store signals thus distributed into frame memories (135A), (135B) of 2 channels, and to distribute a recording signal from a recording system (110) by a second data distribution switch (134) as cause signals of crosstalk signals included in reproduction signals to store signals thus distributed into frame memories to generate pseudo crosstalk signals of respective channels by crosstalk cancellers (136A), (136B) on the basis of reproduction signals and cause signals of respective channels which are read out from the frame memories to cancel, ev

Abstract: A write once disc allowing management of a data area, a method of managing the data area of the write once disc, an apparatus recording data on the write once disc, an apparatus and method of reproducing data from a write once disc. The write once disc, includes a lead-in zone, a data area, and a lead-out zone. The write once disc includes a predetermined area storing area allocation information which indicates whether at least one section of the data area is allocated for disc defect management. In the disc and method, area allocation information specifying a structure of the data area is recorded on the disc, thus allowing a recording/reproducing apparatus to recognize the data area structure. Therefore, allocating areas, such as a spare area, for disc defect management other than an area for storing user data, to the data area is possible. The allocation of the areas for disc defect management to the data area enables effective use of the write once disc.

Abstract: An equalizer for a high density optical disc reproducing apparatus and an equalizing method therefore are provided. The equalizer includes: a non-linear transformer, which transforms an input signal according to predetermined threshold levels; a cosine transform filter, which inverts phases of high frequency spectrum components of an output signal of the non-linear transformer; a high boost filter, which increases amplitudes of high frequency spectrum components of the input signal; and an adder, which adds an output signal of the cosine transform filter with an output signal of the high boost filter. Therefore, the equalizer can increase recording density of the optical disc in the high density optical disc reproducing apparatus and accordingly increase recording amount of information, by reducing inter-signal interference (ISI) and increasing a signal-to-noise ratio in the output signal of the equalizer. Also, the equalizer has a simple configuration.

Abstract: A recording and reproducing apparatus includes a reproduction signal detection unit reproducing a two-dimensional pattern previously recorded on a holographic recording medium or user data recorded on the holographic recording medium, a reference pattern storage unit previously storing a reference pattern to be provided when the two-dimensional pattern is reproduced, a correction information generation unit comparing a reproduction reference pattern signal corresponding to the reproduced two-dimensional pattern with the stored reference pattern and removing fixed distortion contained in the reproduction reference pattern signal to generate correction information used for reproducing the reference pattern from the reproduction reference pattern signal, a correction information storage unit storing the correction information, and a distortion correction unit performing a correction calculation for a reproduction data signal using the correction information to generate corrected reproduction data from which the

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 device for recording and/or reading a record carrier has an optical head with a laser for generating a beam via a scanning spot on a track of the carrier. A detector detects a read signal and a sensor detects a sense signal from the beam. A control unit controls the laser power to a desired value. A correction unit generates a correction signal that depends on local optical properties of the record carrier derived from the sense signal measured on at least one part of the track near the scanning spot. The device corrects the power control using the correction signal. Furthermore, the record carrier can have prerecorded control parameters for setting the correction unit.

Abstract: The present invention relates to a method for recovering land pre-pits from a signal obtained from an optical recording medium. According to the invention, the method comprises the steps of: providing a phase locked loop for the land pre-pit signal for the accurate measurement of the phase of the land pre-pits, and generating a corrected wobble signal for rejecting wobble beats.

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: The invention relates to an optical disc device and a control method for the optical disc device. The presence of defects on an optical disc is confirmed by, based on the result of detecting a return light corresponding to a sub-beam spot used for tracking control, which is formed on the preceding side with respect to scan of a main beam spot, suppressing changes in signal level of the light detection result caused upon boosting of the laser power of a laser beam. Also, whether data can be correctly reproduced is determined by, based on the result of detecting a return light corresponding to a sub-beam spot used for tracking control, which is formed on the succeeding side with respect to scan of the main beam spot, suppressing changes in signal level caused upon writing of the data. Therefore, whether data can be correctly reproduced can be confirmed with a simple construction while effectively avoiding a reduction of the data transfer rate.

Abstract: The object of the present invention is to provide a data recording method and optic recording medium that is capable of reproducing address data accurately by reducing the correlation of address data between adjacent tracks, reducing the effect of cross-talk between adjacent tracks on the recording clock and by making it possible to apply a cross-talk canceller to the wobble signal. The data-recording method of recording data while controlling the correlation between a first data string and a second data string that are contained in recording data, and is provided with a selecting process of selecting inversion/no inversion of first data string such that the correlation between first data string and second data string is reduced; and a recording process of recording first data string according to selected inversion/no inversion polarity, and recording control code that indicates whether inversion/no inversion was selected for first data string.

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: 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: 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: An optical disk device which performs data recording and reproduction with regard to an optical disk on which pre-pit information for specifying an address is formed. An optical disk is irradiated with a laser beam and return light from the optical disk is detected by two photodetectors which are disposed in the radial direction. After the levels of two signals from the photodetectors are limited, a difference between these signals is calculated. Due to the limitation of the levels, noise during the recording power period is removed so that pre-pit information during the reproducing power period, namely during the space period, is extracted. Further, by calculating a difference between the two signals from the photodetectors, pre-pit information during the recording power period is extracted.

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 ?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 ?d within a specified range of change. At this time, the CPU 17 sets the delay amount ?d, which minimizes the jitter value found by the jitter detection unit 16 according to the CTC output signal, for the CTC unit 15. This makes it possible to set the optimum delay amount ?d when adjusting the delay, even when there is little steady cross-talk.

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: A data recording method for calculating a digital sum value (DSV) corresponding to a proportion of positive data and negative data included in predetermined data ranges, selecting a resync pattern to be inserted between the data ranges according to the DSV, and inserting the selected resync pattern between the data ranges, has a step of selecting a resync pattern that minimizes differences in DSV between the data ranges.

Abstract: In a cross-talk canceller (CTC) that removes the cross-talk from the adjacent tracks that is contained in the reproduction signal from the main track, a sample-value series S1? for the reproduction signal from the adjacent track is input to a correlation-detection unit to find its correlation with the signal pattern of the signal output from the CTC that is detected by a pattern-detection unit, and then it passes through one of the correction-coefficient units that is connected by the switch and then integrated by the integrator, and the tap coefficient used by the variable filter of the CTC is obtained to a narrow control frequency zone.

Abstract: A method and circuit for providing a playback signal which is compensated for time delay. The circuit includes a time delay compensator for detecting a time difference between outputs of a photodetector and temporally matching part of the outputs of the photodetector and another part of the outputs of the photodetector, between which the time difference occurs, to compensate for time delay between different outputs of the photodetector, and an operational unit for summing the part of the outputs of the photodetector, which is compensated for the time delay, and the other part of the outputs of the photodetector to provide a playback signal. Accordingly, the circuit compensates for the time delay between the outputs of the photodetector, thereby increasing the degree of modulation of the data playback signal.

Abstract: A method of recording data on a recording medium includes mapping the data to a set of write symbols wherein each write symbol represents more than one bit of the data. The set of write symbols is defined by defining a set of variable write parameters; generating a plurality of candidate write symbols that specify different values for the variable write parameters; generating a plurality of readout waveforms produced by the plurality of candidate write symbols; analyzing the readout waveforms to determine desired set of readout waveforms; and selecting selected ones of the plurality of candidate write symbols that correspond to the desired readout waveforms to be included in the set of write symbols. The data is written to the medium using the write symbols.

Abstract: A method for determining a direct current (DC) level involved in an alternating current signal is provided. The alternating current signal is transmitted from an amplifier to an A/D (analog-to-digital) converter. When any of the extreme values of the alternating current signal is beyond the input range of the A/D converter, the alternating current signal is shifted to make both of the peak and bottom values located within the input range of the A/D converter. Then, the real extreme values are realized according to the shift level(s), the relative peak and bottom values realized after the shifting procedure, and the input range of the A/D converter. Finally, the DC level is determined according to the real peak and bottom values.

Abstract: A disk reproducing apparatus includes a variable gain amplifier (VCA) (32), and the VCA applies a radial push-pull signal including an address signal and an FCM leakage-in signal to a switch (38). The switch outputs only the address signal to a peak-hold circuit (40) on the basis of an FCM mask signal from a mask signal generation circuit (36). The peak-hold circuit generates a peak-hold signal of the address signal so as to be output to a DSP (30), and the DSP controls a gain of the VCA on the basis of the peak-hold signal. Then, the radial push-pull signal in which the gain is controlled on the basis of the address signal is applied to an address detection circuit (42), and the address signal is detected therein.

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: 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: A multivalued information recording method in which energy applied to information units on a recording medium is varied to record multivalued information. In accordance with a relationship between the multivalued information in a predetermined information unit and the multivalued information in information units adjacent to the predetermined information unit, the energy applied to the predetermined information unit is decided.

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

Abstract: User data is recorded in a recording medium while being linked in units of a fixed length packet, and information indicative of this fact is written to the recording medium. At the time of reading the user data, the position of data linking block can be detected by making reference to the identification information, whereby the excessive run-out blocks which would be otherwise requisite to detect the position of the data linking block are made unnecessary. At the time of data linking, a part where data in the run-in block is missing is filled with correct data, thus the run-in block can correctly be read, whereby the excessive run-in blocks which would otherwise be requisite are made unnecessary.

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.