Abstract: An information recording apparatus having an energy beam generator for generating an energy beam, a power adjusting mechanism for setting a power level of the energy beam to a first power level state and a second power level state which is higher than the first power level state and a circuit for generating a basic recording pattern to record a recording medium. When a period of a recording timing generating clock in a recording mode is T, and a relative velocity of the energy beam and the recording medium is v, the circuit forming a sequence of the first and second power level states so as to effect recording.

Abstract: The present invention relates to a modulated signal generator capable of carrying out signal processing at a higher speed or capable of supporting a special format and a new format with ease. A modulation processing storing unit 130 has a modulation processing program required for producing an optical disc master 320 stored therein in advance. Information data recorded in an master optical disc 310 is reproduced by an information reproducing unit 110 and is outputted to a modulation controller 120. The modulation controller 120 carries out the signal modulation processing onto the reproduced information data in accordance with the signal modulation processing program so as to generate a data stream and stores the data stream in a modulated information storing unit 140 as necessary.

Abstract: A write pulse generator is provided with an adjusting section which adjusts a width of write pulses to be generated, a plurality of registers in which control values of adjusting made by the adjusting section are set, a selecting section which selects a control value from the registers and supplies the control value to the adjusting section, and a timing generator. The registers are successively arranged in a plurality of stages so that the control values are successively copied to the registers in subsequent stages. The timing generator generates timings at which the control values are successively copied to the registers in the subsequent stages. The selecting section selects and supplies to the adjusting section the control value held by a register in a final stage.

Abstract: A recording medium with a data format is provided. The data format includes frames and an ECC block. Each of the frames includes a plurality of n-level data, n being an integer satisfying n?3, a clock mark that is n-level data for sampling the n-level data, and a frame sync that is n-level data for indicating a break point of the n-level data of a predetermined amount. The ECC block is a data block for error correction using a product code. The ECC block is formed by binary data of J×K words, where J is a natural number indicating the number of valid binary data in each frame, and K is a natural number indicating the number of frames when the n-level data are converted into binary data.

Abstract: A method and device for recording information in units on a partly recorded writable record carrier, e.g. an optical disc. The information is recorded in a track represented by series of marks of different runlengths between a minimum runlength and a maximum runlength and synchronizing patterns of marks, which patterns do not occur in the series of marks and comprise at least one long mark of at least the maximum runlength. At least one information unit is encoded into a modulated signal comprising signal elements corresponding to said marks. The track is scanned up to a link position before a selected one of said addressable locations, and the modulated signal is recorded from the link position. The modulated signal is provided at the begin and/or at the end with a link signal element corresponding to a mark of at most the minimum runlength.

Abstract: A predetermined synchronization pattern (40), a so-called VFO field, in, for example, the headers 3 of an information carrier. The predetermined synchronization pattern contains a first part with marks having a first length of (d+1) times the channel bit length, and spaces having a second length of (d+1) times the channel bit length, and a second part with marks having a third length of (k+1) times the channel bit length and spaces having a fourth length of (k+1) times the channel bit length and a third part, which third part contains marks having a length of (k?d) times the channel bit length and spaces having a length of (k?d) times the channel bit length. This sequence of patterns is advantageous for setting the dynamic range of an Automatic Gain Controlled (AGC) amplifier located within a device reading the information carrier.

Abstract: The present invention relates to method and apparatus for suppressing a DC component of coded sequence with no additional bit for suppressing a DC component, and for decoding the coded sequence. The present modulating method includes modulating the source data to a coded data based on at least one mapping table, the mapping table including a first table and a second table containing coded data corresponding to the source data, the first table being a 2/3 table containing 3-bit coded data for 2-bit source data, and the second table being a 4/6 table containing 6-bit coded data for 4-bit source data, wherein one of the first table and the second table is selected according to a bit sequence of the source data; and recording the coded data onto the optical recording medium.

Abstract: The DVD recording method is intended to increase the number of cycles allowed for recording on the disk an enormous number of times. This method comprises generating two data streams by using a plurality of code mapping variants prepared for coding input data, quasi-randomly selecting one of the plurality of code mapping variants, if absolute DSVs of the two streams are substantially equal, and converting into recording code sequences. This method prevents deterioration of the disk particularly in the management area and increases the number of cycles allowed for rewriting.

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 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: The present invention relates to an information recording apparatus, an information recording method, an information recording medium, an information reproducing apparatus and an information reproducing method by which in the case in which the present invention is applied to an optical disk system by, for example, a compact disk or the like and data or the like related to copyright is recorded by partial change of a pit shape or the like, the data can be reproduced with certainty without repeatedly recording the data. According to the present invention, with regard to a defect having a size by which at least main data can be reproduced correctly, 1 bit of sub-data SB is allocated to a pit row or the like having a predetermined length or more such that the sub-data SB can be reproduced correctly.

Abstract: During manufacturing of optical disks, mastering equipment inserts marks (“high frequency wobble marks” or “HFWMs”) into the wobble of the groove on optical disks to store data. The presence of a HFWM at a zero crossing of the wobble indicates an active bit and the absence of the HFWM indicates an inactive bit. The zero crossing is, for example, a negative zero crossing. A matched filter is used to detect the shape of the HFWMs. If a HFWM is detected during a wobble cycle, an active bit is saved in a register or a memory. If a HFWM is not detected during a wobble cycle, an inactive bit is saved in a register or a memory. The active and inactive bits may be coded bits that must be decoded to data bits. The data bits include information such as a synchronization mark, a sector identification data, and an error detection code.

Abstract: An information encoding apparatus for encoding N pieces of information, the information encoding apparatus includes a scrambling pattern generation section for generating M scrambling patterns (N>M?1; where M and N are each an integer); a scrambled information generation section for applying, to each of the N pieces of information, one corresponding scrambling pattern among the M scrambling patterns so as to generate N pieces of scrambled information; and an encoded information generation section for supplying the N pieces of scrambled information with N parities, respectively, so as to generate encoded information. Each of at least one of the M scrambling patterns is applied to two or more of the N pieces of information.

Abstract: An information recording method using a recording medium having a first state by a first power level of an energy beam and a second state by a second power level of the energy beam higher than the first power level. When a period of a recording time generating clock in a recording mode is T, and a relative velocity of the energy beam and the recording medium is V, the method includes forming a sequence of the second state with length avT (first mark), the first state with length ivT (first space) following the first mark, the second state with length mvT (second mark) following the first space, the first state with length jvT (second space) following the second mark and the second state with length bvT (third mark) following the second space as a first small recording pattern.

Abstract: In an information recording method and apparatus which is capable of improving a recording density of an optical recording medium, a carrier signal is detected in an optical recording medium preformatted as first unit regions by modulating a synchronous signal dividing a track into first unit regions having a certain volume and address information indicating the first unit regions as time information format, and the address information is restored by the detected carrier signal. The restored address information is converted into a linear code, the converted linear code is counted with a clock signal varied in accordance with a volume of the second unit regions different from a volume of the first unit regions. Logical address information indicating the second unit regions is generated, and a record clock signal varied in accordance with a recording density of the second unit regions is generated, accordingly a recording density of an optical recording medium can improve.

Abstract: A recording method of a multilayer recording medium includes a first initializing step of initializing a lower recording layer based on a first initializing condition and a second initializing step of initializing an upper recording layer on the basis of a second initializing condition different from the first initializing condition. The second initializing condition is determined so that a transmittance of the recording layer after execution of the second initializing step is approximately equal to a transmittance of the recording layer after a predetermined data signal is recorded on an upper recording layer.

Abstract: In a data arrangement of a CD-ROM format, data in which DSV control data cannot be placed due to a restriction on the format is followed by control data of two bytes. Main data in which any data cannot be placed is followed by a special control data sequence of two bytes. As a result, after a data sequence of which it is unknown whether the start bit is plus or minus, the sign of the start bit of a diverging control data sequence preceded by the special control data sequence can be kept constant. Consequently, DSV values can be deviated in one direction.

Abstract: A data recording apparatus comprising a read section for reading image data and/or audio data recorded on a first recording medium, and a write section for recording the aforementioned read image data and/or audio data on a second recording medium. This data recording apparatus is further provided with an identification information determining section for determining whether identification information is recorded in the aforementioned recording medium or not, to ensure that, only when the aforementioned identification information determining section has determined that the identification information is recorded, the write section records the read image data/audio data on the second recording medium.

Abstract: The present invention relates to a method and system for multi-dimensionally coding and/or decoding an information to/from a lattice structure representing bit positions of said coded information in at least two dimensions. Encoding and/or decoding is performed by using a close-packed lattice structure, preferably a quasi-hexagonal lattice structure. In particular, at least partial quasi-hexagonal clusters consisting of one central bit and a plurality of nearest neighboring bits can be defined, and a code constraint can be applied such that for each of said at least partial quasi-hexagonal clusters a predetermined minimum number of said nearest neighboring bits are of the same bit state as said central bit. Thereby, intersymbol interferences can be minimized at a high code efficiency.

Abstract: A data accumulating apparatus, comprising: storage media; receiving means for receiving digital raw data about specific information from an external electronic device; first accumulating means for accumulating the digital raw data received by the receiving means into the storage media; producing means for producing first data equal to the digital raw data accumulated in the storage media; compressing means for compressing the first data produced by the producing means to produce coded data in association with the digital raw data accumulated in the storage media; and second accumulating means for accumulating the digital coded data produced by the compressing means into the storage media.

Abstract: According to the present invention, in an optical disk apparatus constructed to supply signals for controlling a semiconductor laser drive circuit provided to an optical pickup from a signal processing circuit through a flexible cable, the semiconductor laser drive circuit is so constructed as to generate a drive current signal for the semiconductor laser on the basis of a binary signal and a clock signal which are supplied from the signal processing circuit through the flexible cable and the signal processing circuit is so constructed as to stop supplying the block signal to the semiconductor laser drive circuit through the flexible cable during reproduction of data, and to start supplying the clock signal to the semiconductor laser drive circuit before recording of data.

Abstract: The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method divides a data word, which a sync signal is to be added in front or rear of when it is written in a recording medium, into two or more word segments, generates for each word segment a number of intermediate sequences by combining mutually different digital words with that word segment, scrambles these intermediate sequences to form alternative sequences, translates each alternative sequence into a (d, k) constrained sequence, checks how many undesired sub-sequences are contained in each (d, k) constrained sequence, and selects one (d, k) constrained sequence for recording on an optical or magneto-optical recording medium among the (d, k) constrained sequences not having the undesired sub-sequence. Applying this method to a modulating device, DSV control can be conducted by much simpler hardware.

Abstract: Methods are provided for overwriting data in a probe-based data storage device (1) wherein data is represented by the presence and absence of pits formed in a storage surface (4) by a probe of the device. Input data is first coded such that successive bits of a first value in the coded input data are separated by at least one bit of the other value. Overwrite data bits v0, v1, v2, . . . , are generated from the coded input data bits b0, b1, b2, . . . , and the overwrite data bits v0, v1, v2, . . . , are then used to overwrite data on the storage surface (4). According to a first method, the overwrite data bits are generated such that, if a pit represents a bit of said first value in the data storage device (1) then vi={overscore (b)}i−1, for i≧1 and v0 has said first value, and if a pit represents a bit of said other value in the data storage device (1) then vi=bi−1 for i≧1 and v0 has said other value.

Abstract: A recording and reproducing area and a reproduction-only area are formed by wobbling a groove formed in a spiral fashion to form a track to be tracked on a disk. The recording and reproducing area has address information recorded by wobbling of the groove and information recorded and reproduced by phase change marks on the track formed by the groove where the address information is recorded. The reproduction-only area has prerecorded information recorded by wobbling of the groove.

Abstract: A recording and/or reproducing apparatus for use with an information storage medium that includes a lead-in area, a user data area, and a lead-out area is read by a recording and/or reproducing apparatus. Information about whether the information storage medium is compatible with a drive following an older version of standards is recorded in at least one of the lead-in and lead-out areas. Accordingly, the recording performance thereof is improved, and a drive following an older version of standards can record data on or reproduce data from a newer version of an information storage medium.

Abstract: A high speed, high accuracy parallel/serial conversion circuit, wherein a PLL circuit 50 receives as input and locks a clock CLK, and supplies the same to different parts of an apparatus; the PLL circuit 50 controls a 16-tap ring oscillator 60 to shift the phase of a clock frequency-locked to a reference clock so as to generate 32 types of phase shift pulses CK0 to CK31 shifted in phase by increments of {fraction (1/32)} of the clock width from the reference clock by the differential outputs of the 16 taps and supplies the same to a P/S conversion circuit 70; and the P/S conversion circuit 70 generates fine width pulses with {fraction (1/32)} pulse widths based on the 32 types of phase shift pulses shifted in phase by increments of {fraction (1/32)}. Further, the fine width pulses are used to convert parallel signals output from a RAM 30 and a decoder 40 to a serial signal.

Abstract: Creation and detection of synchronization marks for a multilevel data storage medium is disclosed. A sequence of symbols is generated and the sequence of symbols is written to the multilevel data storage medium. A corresponding sequence may be generated by a detector and correlated with read data to detect the synchronization mark.

Abstract: For encoding a current data word to be encoded, a most suitable redundant signal for the current data word to be encoded is generated by referring to a next data word to be encoded, that is, using a look-ahead decision method. The current data word to be encoded is encoded by using this redundant signal. A low-frequency component of the encoded data is effectively suppressed without decreasing encoding efficiency, by using both a regular substitution code and a stochastic substitution code, and a look-ahead determination algorithm for changing the length of words of a data segment, based on stochastic occurrence of a substitution word.

Abstract: A recording method for converting m-bit data into n-bit (where n>m) bit data whose run length is restricted and recoding the converted data on a recording medium, the recording method comprising the steps of when at least preceded data is data containing a special data pattern, lightening the restriction of the run length; and recording data so that the cumulative value of DC components per unit time increase when the data is reproduced in the state that the run length is restricted.

Abstract: In a decoding apparatus (30), power compensation spectrum generation/composition units (371, to 374) adjust power of power compensation spectrums PCSP based on quantization accuracy information, normalization coefficients, gain control information, and power adjustment information. Then, power of the spectrums SP is compensated by replacing spectrums SP being equal to or smaller than a threshold with the power-adjusted power compensation spectrums PCSP, or by adding the power-adjusted power compensation spectrums PCSP to the spectrums SP.

Abstract: The present invention relates to a method and system for multi-dimensionally coding and/or decoding an information to/from a lattice structure representing bit positions of said coded information in at least two dimensions. Encoding and/or decoding is performed by using a close-packed lattice structure, preferably a quasi-hexagonal lattice structure. In particular, at least partial quasi-hexagonal clusters consisting of one central bit and a plurality of nearest neighboring bits can be defined, and a code constraint can be applied such that for each of said at least partial quasi-hexagonal clusters a predetermined minimum number of said nearest neighboring bits are of the same bit state as said central bit. Thereby, intersymbol interferences can be minimized at a high code efficiency.

Abstract: A thermoplastic norbornene resin is purified by using a cleaning liquid to eliminate organic impurities, ionic impurities, metallic impurities, and particles of the resin. The cleaning liquid is selected from 2-propanol and a mixed solvent of 2-propanol and water. A substrate for a magnetic recording medium of the invention is fabricated by injection-molding the thermoplastic norbornene resin purified by this method. A magnetic recording medium of the invention includes such a substrate, and a magnetic layer, a protective layer, and a liquid lubricant layer sequentially formed on the substrate. A method for manufacturing such a magnetic recording medium is also provided.

Abstract: A method of recording data on a recordable disk so that data is stably reproducible, a method of protecting syncs included in the recorded data, an information storage medium, and an apparatus for reproducing the data recorded on the recordable disk. In the information storage medium, data is recorded in a certain recording unit. The recording unit includes a body and a head. The body includes user data and a first recognizer, and the head is attached in front of the body to protect the body and includes a second recognizer to protect the first recognizer. The second recognizer comprises more patterns than a number of maximum length patterns used to form the first recognizer so that the second recognizer is distinguished from the first recognizer. Thus, even if the data is recorded on the recordable disk at any time, data is properly reproducible.

Abstract: A rewritable recording medium having a synchronizing signal portion recorded with a synchronizing signal information and a data portion recorded with data information after the synchronizing signal portion. Each time the synchronizing signal information is rerecorded, a length of the synchronizing signal portion changes and a start position of the synchronizing signal portion changes.

Abstract: For encoding a current data word to be encoded, a most suitable redundant signal for the current data word to be encoded is generated by referring to a next data word to be encoded, that is, using a look-ahead decision method. The current data word to be encoded is encoded by using this redundant signal. A low-frequency component of the encoded data is effectively suppressed without decreasing encoding efficiency, by using both a regular substitution code and a stochastic substitution code, and a look-ahead determination algorithm for changing the length of words of a data segment, based on stochastic occurrence of a substitution word.

Abstract: A method for recording data comprising: forming recording data by adding a pattern of connection bits selected from among a plurality of patterns of connection bits to the end of an m-bit data symbol, the selected pattern of connection bits causing an increase in an accumulated value of direct-current components per unit time when the n-bit data symbol is a special data symbol and is added to a data symbol other than the special data symbol, when m-bit data is converted into the n-bit data symbol (m<n) and when the pattern of connection bits is selected from among the plurality of patterns of connection bits to decrease the accumulated value of direct-current components per unit time to be added to the end of the m-bit data symbol; and recording the recording data formed and data indicating a recorded location of the special data symbol on a recording medium.

Abstract: A recording medium, such as a high-density and/or read-only recording medium including a data area including at least two data sections and a linking area to link neighboring data sections, the linking area including at least two frame sync signals, where values of the at least two frame sync signals maintain uniqueness, and to methods and apparatuses for forming, recording, and reproducing the recording medium.

Abstract: A CD which cannot practically be copied. A recording method, wherein, when a certain portion of main data is recorded by being encoded by a first encoding method and the other portions of the main data is recorded by being encoded by a second encoding method, an encoding process is performed by the first encoding method so that, when data which is recorded in such a manner that the data encoded by the first encoding method is decoded by a decoding method corresponding to the first encoding method, and thereafter, is further encoded by the second encoding method, is decoded by a decoding method corresponding to the second encoding method, the sum value of DC components per unit time increases.

Abstract: A recording medium, such as a high-density and/or read-only recording medium including a data area including at least two data sections and a linking area to link neighboring data sections, the linking area including dummy data, and to methods and apparatuses for forming, recording, and reproducing the recording medium.

Abstract: The invention relates to a predetermined synchronization pattern (40), a so-called VFO field, in, for example, the headers 3 of an information carrier. The proposed predetermined synchronization pattern (40) consists of sequences of 3T marks and spaces (41), of 8T marks and spaces (42) and of 5T marks and spaces (43). This sequence of patterns is advantageous for setting the dynamic range of an Automatic Gain Controlled (AGC) amplifier located within a device reading the information carrier.

Abstract: Output data of a multiplexer 11 is EFM-modulated by an EFM modulator 12. In the EFM modulation, merging bits that satisfy run length limit conditions Tmin=3 and Tmax=11 are selected. Among them, merging bits that converge DSV are selected. A run length controlling portion 13 detects a particular data pattern that causes DSV to increase as large as a data read error takes place and controls the EFM modulator 12 so that the run length limit conditions of the EFM are loosened. As a result, an increase of DSV is suppressed. Data is reproduced from a data recording medium on which the data has been recorded in such a manner and the reproduced data is decoded. The decoded data is re-encoded so as to record it to another recoding medium. When the data pattern is re-encoded, DSV increases. As a result, data cannot be correctly reproduced from the other recording medium. Consequently, a copying operation can be prevented.

Abstract: The present invention is an optical drive and corresponding optical disc that diverge from their binary (2-bit) predecessors by storing and reading data in higher level number systems from octal (8-bit) to 1024-bit (1 kilobit). As described herein, this allows for the production of extremely versatile discs with greatly increased capacities and highly enhanced encryption capabilities. This format also enables diverse industries to tailor the data structure of a disc to complement their individual needs.

Abstract: On an information record medium (10, 11), record information can be recorded one time or a plurality of times by a predetermined record format. An apparatus for manufacturing the information record medium by using a stamper (27, 28) is provided with an embossed pit array forming device (20 to 26, 50) for forming on the stamper as an embossed pit array, pre-record data (SFi) which is a predetermined data row to disable overwriting on the record information in a pre-record area, which is set in advance in a range including an area (13c) assigned to information required to control a reproduction of the record information, which is recorded by the predetermined record format.

Abstract: A system for modulating digital binary data to be recorded on a recording medium comprises the generation of channel bits of the digital binary data to be recorded according to a standard for the recording medium with the exception that a maximum run length larger than that defined in the standard is obtained and/or the merging decision is influenced on basis of a random noise in a predetermined pattern or in at least one predetermined position on said recording medium and/or by recording at least one part comprising at least one predetermined repetitive bit pattern which normally, i.e. according to the standard for the recording medium, encodes into channel bits having a spectral distribution that shows at least one range of frequencies with a characteristic amplitude distribution.

Abstract: An optical disk recording apparatus is provided that includes an optical pickup, an image encoder that generates data corresponding to a visual image to be drawn in a recording region of an optical disk, an LD control unit that controls the optical pickup and records long pits and long spaces that form the visual image in the recording region, and a system controller that determines whether no reproducible data are stored in the recording region and records the visual image by controlling the LD control unit. Since the reflective ratio of the region where the long pits are formed changes, the region becomes visible to a user. Accordingly, any characters and figures designated by an external device can be visibly recorded on the data recording surface of the optical disk.

Abstract: The present invention aims at providing an inexpensive optical information storing device that produces reduced cross talk. An optical information storing device has a cyclic data output circuit 14—1 that outputs cyclic data in which values are repeated every 5 bytes, and an EXOR circuit 14—2 that calculates the exclusive-OR (EXOR) of recording data input thereto via a buffer 14—5 and the cyclic data and inputs the calculation result to an RLL modulation circuit 14—3 as data to be recorded.

Abstract: A visible image forming method is performed for forming a visible image on an optical disk by an optical disk recording apparatus, which is designed for applying a laser beam onto an optical disk according to first recording data of a predetermined format to form pits having lengths specified by the first recording data. First, a generating step is performed for generating second recording data by embedding image formation data of a visible image in a part of a predetermined format which is the same as predetermined for the first recording data. Second, an extracting step is performed for extracting the image formation data of the visible image from the second recording data of the predetermined format. Then, a forming step is performed for forming pits in the optical disk according to the extracted image formation data so as to form the visible image on the optical disk.

Abstract: Polycarbonate compositions incorporating long chain alkylphenol endgroups, for example cardanol, show enhanced pit replication characteristics when molded into optical disks. The enhancement in molding performance is especially pronounced at the shortest mold cycle times tested. Thus, a blend of 75 parts by weight bisphenol A polycarbonate 92 percent encapped with phenol, and 25 parts by weight bisphenol A polycarbonate about 100 percent endcapped with cardanol showed enhanced pit replication performance in optical disk molding trials relative to the same bisphenol A polycarbonate alone and analogous blends utilizing short chain alkylphenols.

Abstract: The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method generates for each data word a number of intermediate sequences by combining mutually different digital words with that data word, scrambles these intermediate sequences, translates each scrambled sequence into a (d,k) constrained sequence, detects running digital sum (RDS) every bit for each translated (d,k) constrained sequence while counting sign changes of each RDS, selects one sequence of which RDS changes most in sign among the (d,k) constrained sequences after discarding every sequence of which maximum value of RDS is beyond a preset threshold, and records the selected sequence onto a recordable medium such as an optical disk or a magneto-optical disk. The present invention can suppress DC component more remarkably in case that a sequence becomes longer.

Abstract: The present invention separates MTF into a plus frequency region and a minus frequency region and uses the plus frequency region and the minus frequency region to thereby enable an effectively usable frequency region to be doubled in effect. Digital information to be recorded on an optical disk medium is recorded as independent signals of, respectively, a light beam reflected or diffracted forward and a light beam reflected or diffracted backward with respect to a direction of traveling of a track on the optical disk medium. At the time of producing an optical disk medium, digital information is divided into two pieces, a complex modulating signal is generated by changing a plus frequency component and a minus frequency component according to the pieces of the divided digital information, and a laser beam is modulated on the basis of the complex modulating signal.