A switching power converting apparatus includes a coil unit, a bipolar junction transistor (BJT) controlling power transfer through the coil unit, and a current sensing resistor sensing a current flowing through the BJT so as to produce a sensed voltage thereacross. A switching controller includes a current source supplying a first current, a current generating module generating, based on an input voltage associated with the sensed voltage, a second current, which is proportional to the current flowing through the BJT, a multiplexing module selecting one of the first and second currents as an output current, and a driving module outputting, based on the output current, a driving current, which is proportional to the output current, to the BJT to thereby conduct the BJT.

A flyback type switching power supply includes between P and N of a direct current output a sudden load change detector circuit, which normally has no power consumption, that detects only a transient fluctuation of a direct current output voltage, and starts the switching of a primary side semiconductor switch when there is no load or a light load, even when the semiconductor switch is in an off state, thereby enabling the detection of the direct current output voltage in a tertiary winding, and suppressing a drop in the direct current output voltage.

Provided is a power conversion system that includes a first transformer adapted to be connected to an AC network, the first transformer including a first primary winding and two first secondary windings, and two power converters, each being connected to a first respective secondary winding. The system further includes a second transformer and a secondary electrical device, the second transformer including a second primary winding and two second secondary windings, each second secondary winding being connected to a respective first secondary winding, and the secondary device being connected to the second primary winding.

Methods and systems for managing link voltages in a power converter, where single phase, three phase or universal systems can be used. Common mode management refers to shifting of voltages in a particular direction to perform transition between input and output ports, in addition to maintaining soft switching property. Voltages in power converters can be freely increasing and decreasing, and thus damage to the circuit can be caused if these voltages change are not controlled.

A noise suppression circuit for a power adapter is disclosed. The noise suppression circuit can reduce or eliminate adapter-induced noise that could interfere with an electronic device powered by the adapter. In one example, the noise suppression circuit can include an active circuit to detect and attenuate or cancel the induced noise. In another example, the noise suppression circuit can include an RLC circuit in parallel with the adapter choke to suppress the induced noise at the operating frequencies of the powered electronic device. In still another example, the noise suppression circuit can include a modified adapter Y capacitor connection so as to bypass the adapter choke, thereby reducing or eliminating the choke's induced noise.

A power source circuit includes a switching circuit 4 that converts a direct current voltage obtained by converting an alternating voltage from an alternating power source input through a pair of power supply lines 2 and 3 into a predetermined direct current voltage by a switching operation. A fuse 5 is provided on one power supply line 2. A series circuit 9 including a first line bypass capacitor 7 and a resistor element 8 is connected between one power supply line 2 and a ground 6. A second line bypass capacitor 10 is connected between the other power supply line 3 and the ground 6. Imbalance of the circuit by an excess current protection element is prevented to reduce common mode noise.

Disclosed is a grid-connected inverter and a method for filtering AC output thereof. The grid-connected inverter includes an AC output filter which includes two or more switchable filtering modules, with the power capacity of each filtering module corresponding to a different output power of the grid-connected inverter; a monitoring module which is used to perform realtime monitoring on voltage and current outputted by the grid-connected inverter; and a control circuit which is used to calculate an output power grade of the grid-connected inverter according to the voltage and the current monitored by the monitoring module and control switching to the filtering module having a corresponding power capacity according to the power grade, the power grade being selected from a plurality of power grades which are divided according to power capacities of the filtering modules.

Methods and apparatuses for a soft-start function with auto-disable are described. Such methods and apparatuses can gradually increase a voltage towards a reference voltage using a ramp generator and a control loop and can disable the ramp generator and the control loop once the voltage has reached the reference voltage.

Embodiments provide a magnetic flux conversion device (MFCD) that may produce a regulated output signal with a target value (e.g., target voltage and/or target current) from a source signal on a power line. The MFCD may include a secondary stage configured to be inductively coupled with the power line. The source signal may cause a secondary electrical signal to flow in the secondary stage. A regulator module may be coupled to the secondary stage and configured to produce the output signal with the target value across output nodes by sensing the output signal and shunting the secondary stage if a value of the output signal is above the target value.

There is provided an even-level inverter, including: a voltage-dividing circuit dividing input DC power into an even number of voltage levels; a plurality of switching devices connected to individual nodes of the voltage-dividing circuit having the even number of voltage levels; and a bidirectional switching device connected to the individual nodes of the voltage-dividing circuit through at least one of the plurality of switching devices and including at least two transistors. According to the present invention, the bidirectional switching device is implemented without a diode to thereby reduce conduction loss caused due to an anti-parallel diode included in the related art bidirectional switching device, and a neutral point of the voltage-dividing circuit is electrically separated from the switching devices to thereby control reactive power.

A voltage regulator coupled to an unregulated DC input voltage source by an input terminal, and to a load by an output terminal is disclosed. The voltage regulator converts an input voltage at the input terminal to an output voltage at the output terminal. The voltage regulator includes one or more slaves, and each slave includes a switching circuit which serves as a power switch for alternately coupling and decoupling the input terminal to an intermediate node. The voltage regulator also includes a filter coupled to the slaves, the filter including one or more inductor banks each of which having a predetermined number of inductors.

The invention discloses a voltage source converter and a voltage source converter system. The voltage source converter comprises: a multi-level voltage source converter, being adapted to output a multiple levels of a first voltage at one of two first output terminals through a multiple of first conducting paths; a first energy store; and a first switching element, being arranged to directly connected with the first output terminal, and being adapted to switch the first energy store in or out of the first conducting path so as to combine a level of the voltage of the first energy store with the level of the first voltage as a second voltage output at a second output terminal. By having the topology as above, the voltage class of each of the power semiconductors can be kept lower with the number of the power semiconductors unchanged. Besides, VDRM is lowed as compared to conventional topology. This renders the reduction of the cost and the increase of the liability.

A Low Forward Voltage Rectifier (LFVR) circuit includes a bipolar transistor, a parallel diode, and a capacitive current splitting network. The LFVR circuit, when it is performing a rectifying function, conducts the forward current from a first node to a second node provided that the voltage from the first node to the second node is adequately positive. The capacitive current splitting network causes a portion of the forward current to be a base current of the bipolar transistor, thereby biasing the transistor so that the forward current experiences a low forward voltage drop across the transistor. The LFVR circuit sees use in as a rectifier in many different types of switching power converters, including in flyback, Cuk, SEPIC, boost, buck-boost, PFC, half-bridge resonant, and full-bridge resonant converters. Due to the low forward voltage drop across the LFVR, converter efficiency is improved.

A high voltage full wave rectifier and doubler circuit having complementary serially connected low voltage MOSFET stacks to provide high voltage capability. The state of the MOSFETs in the MOSFET stacks is controlled by means of resistors coupled between the circuit's outputs and a time varying input signal. The resistance values of the resistors are selected to maintain operation of the stacked MOSFETs below their breakdown voltages.

Systems and methods are provided for pre-charging the DC bus on a motor drive. Pre-charging techniques involve pre-charge circuitry including a manual switch, an automatic switch, and pre-charge control circuitry to switch the automatic switch between pre-charge and pre-charge bypass modes in response to an initialized pre-charge operation, input voltage sags, and so forth. In some embodiments, the pre-charge operation may be initialized by switching the manual switch closed. In some embodiments, the pre-charge operation may also be initialized by a detected voltage sag on the DC bus. The pre-charge circuitry may also be configured to disconnect to isolate a motor drive from the common DC bus under certain fault conditions.

System and method for regulating a power converter. A system for regulating a power converter includes a controller, a first switch, and a second switch. The controller is configured to generate a first switching signal and a second switching signal. The first switch is configured to receive the first switching signal, the first switch being coupled to an auxiliary winding of the power converter further including a primary winding and a secondary winding. The second switch is configured to receive the second switching signal and coupled to the primary winding of the power converter. The controller is further configured to, change, at a first time, the second switching signal to open the second switch, maintain, from the first time to a second time, the first switching signal to keep the first switch open, and change, at the second time, the first switching signal to close the first switch.

A controller for a power converter and method of operating the same employable with a bridge rectifier having first and second synchronous rectifier switches. In one embodiment, the controller includes an amplifier configured to enable a turn-on delay for the first synchronous rectifier switch. The controller also includes a discharge switch having first and second switched terminals coupled to gate and source terminals, respectively, of the first synchronous rectifier switch and configured to discharge a gate-to-source capacitance of the first synchronous rectifier switch to enable a turn off thereof.

An aspect of the present invention relates to glass for a magnetic recording medium substrate, which includes essential components in the form of SiO2, Li2O, Na2O, and one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO, wherein a molar ratio of a content of MgO to a combined content of MgO, CaO, SrO, and BaO (MgO/(MgO+CaO+SrO+BaO)) is equal to or greater than 0.80, and which has a Young's modulus of equal to or greater than 80 GPa, and a glass transition temperature of equal to or greater than 620° C.

An apparatus for energy assisted magnetic recording of a storage disk include a plurality of dielectric waveguide cores configured to direct received incident light energy to a target, and a near field transducer (NFT) configured to focus light energy received from the plurality of waveguide cores and to transmit the focused light energy onto the storage disk surface to generate a heating spot on the storage disk. The NFT includes a plurality of propagating surface plasmon polariton (PSPP) elements that are energized by the light energy from the waveguide cores. Each of the PSPP elements has a plasmonic metal bar disposed above a single waveguide core in a longitudinal alignment. Each metal bar has a width at least twice the width of the heating spot generated on the storage disk.

A thermally assisted magnetic recording medium (1) includes a substrate (101), an underlayer (3) that is formed above the substrate (101), and a magnetic layer (107) that is formed on the underlayer (3) and contains an alloy having an L10 structure as a main component. The underlayer (3) is formed by continuously laminating a first underlayer (104) having a BCC structure with a lattice constant that is 0.302 to 0.332 nm, a second underlayer (105) that has a NaCl structure including C, and a third underlayer (106) that is composed of MgO.

An optical head device (11) provided with: an optical element (36) for transmissively diffracting a light beam emitted from a semiconductor laser (34), generating a zero-order diffracted light beam and ±1-order diffracted light beams; and a photodetector (40) for receiving the zero-order diffracted light beam and the +1-order diffracted light beam after reflection from an optical disc (2). The photodetector (40) includes a primary light receiving section (400) for receiving the zero-order diffracted light beam, and a first secondary light receiving section (401) disposed outward from the primary light receiving section (400). The first secondary light receiving section (401) is positioned to detect an outer portion of the received light spot of the +1-order diffracted light beam, performs photoelectric conversion of this portion, and outputs a secondary detected signal.

Technologies are described herein for utilizing a head heater to test temperature stability of a head of a storage device and to prevent the head from operating in an unstable temperature condition. A first power level may be applied to a head heater of a head in a storage device, the first power level configured to simulate a temperature condition in the head. An instability of the head is determined and the temperature condition and the instability of the head are recorded in a memory. The process may be repeated to develop a range of temperature conditions in which the head exhibits instability. The range of temperature conditions and the head heater may then be utilized to prevent the head from operating in an unstable temperature condition during normal operation.

An optical recording medium includes a recording and reading layer that is previously staked or formed afterword and has no concavo-convex pattern for tracking control, and a servo layer in which a concavo-convex pattern or a groove for tracking control is formed. Information can be recorded in the recording and reading layer while tracking is performed using the servo layer.

The present technology relates to an optical recording medium for realizing an optical recording medium capable of high-capacity recording. A groove and a land are formed, the groove being concave and the land being convex when seen from a side of a laser light incident surface, both of the groove and the land being recording tracks where recording or reproduction of information is performed. According to this recording layer, a pitch between the groove and the land that are adjacent recording tracks is within a range of 250 nm to 200 nm. Moreover, recording or reproduction of information is performed with respect to the recording tracks by irradiation of laser light whose wavelength is 400 nm to 415 nm by an optical system whose NA is 0.85±0.1.

A flex circuit including a dual sided interconnect structure to connect electrical components on a head or suspension assembly to head circuitry is described. The dual sided interconnect structure described has application for providing an electrical connection to one or more transducer elements on a slider and one or more elements of a heat assisted magnetic recording HAMR unit. In an illustrated embodiment, a flexible structure or insulating base layer includes one or more slider and heat assisted magnetic recording traces coupled to one or more slider or HAMR bond pads on an interconnect portion. As disclosed, the slider bond pads are on the obverse side of the flexible structure and the HAMR bond pads include a reverse side bonding surface to form reverse side bond pads to connect to one or more electrical or heating elements on the HAMR unit.

A return path section includes first and second yoke portions and first, second and third columnar portions. The first and second yoke portions and the first columnar portion are located on the same side in the direction of travel of the recording medium relative to a wave guide core. The second and third columnar portions are located on opposite sides of a plasmon generator and connected to a shield. The first yoke portion connects a main pole to the first columnar portion. The second yoke portion connects the first columnar portion to the second and third columnar portions. A coil is wound around the first columnar portion.

Provided are an optical pickup device and an optical disk drive including the same. The optical pickup device includes a quarter-wave plate (QWP) that is disposed parallel to an objective lens and a reflection mirror that reflects a beam back onto the QWP after the beam passed through the QWP. The optical pickup device also includes a polarization mirror that is disposed between the objective lens and the QWP, and which reflects the beam which is generated from a light source onto the QWP, and allows the beam reflected by the reflection mirror to pass through to the objective lens.

A recording head for recording information on a rotating recording medium of a storage device includes a main magnetic pole which generates a recording magnetic field in a direction perpendicular to a recording medium facing surface of the magnetic recording head, and a light generating element which is provided on a leading side of the main magnetic pole, and generates light for heating the recording layer of the recording medium. The main magnetic pole includes an end surface facing the light generating element that is inclined with respect to the direction perpendicular to the recording medium facing surface toward the light generating element.

In a heat-assisted magnetic recording (HAMR) hard disk drive, a heat-dissipating head slider assembly is described in which the slider is stepped on the disk-opposing side and a HAMR laser module is mounted on the lower surface to assist with dissipation of heat from the laser. The lower surface is a surface of the main body of the slider and is composed primarily of a first material, and the slider may include a heat-dissipating plate that forms the higher stepped surface, where the plate is composed of a second material that has a higher thermal conductivity than the first material, such as silicon.

A digital jukebox (14) allows for playback of a first offering and a second offering. The contents of each offering are individually licensed for public performance at a particular location where the jukebox is found. The jukebox (14) displays advertisements that are selected in response to user interaction with the jukebox or a number of other factors. The jukebox (14) features a screen (18 and 20) that allows user to interact with the jukebox to select offerings, but also to respond to advertising. Jukebox can function in cooperation with a server (12), but in the alternate, can function as an independent and stand-alone device when connection (16) to server (12) is not available.

A method for copy protection in which an audiovisual or audio data is divided into a plurality of portions. The plurality of portions is at least partly scrambled and prepared so as to be stored on a record carrier in the scrambled order. This is done so that a physical position on the record carrier, e.g., a sector of the record carrier, where a respective portions of the divided data is stored depends on the scrambled order.

An optical disk device includes an optical pickup that directs light beams onto a recording surface of an optical disk and receives reflected light, a signal generating unit that generates playback signals based on reflected light received by the optical pickup, an equalizer adjustment unit that performs equalizer adjustment of the playback signals, and an adjustment control unit. The adjustment control unit controls the equalizer adjustment unit so as to perform equalizer adjustment of the playback signals according to the playback signals based on reflected light from a management information area on a recording surface of the optical disk, the management information area including predetermined management information recorded thereon.

Disclosed is an optical information recording and reproducing device capable of recording an interference fringe pattern as a hologram in an optical information recording medium, the interference fringe pattern being formed by a signal beam superimposed with signal information and a reference beam, and also capable of reproducing the signal information from the optical information recording medium, the device having a light source unit to emit light, a light splitting unit to split the light into the reference beam and the signal beam, a spatial light modulation unit to superimpose the signal information on the signal light, and a light detection unit to detect an image reproduced by the reference beam, wherein information about defects on the spatial light modulation unit is recorded in the optical information recording medium.

Once a human operator selects one output channel using a port setting key and SEL key, output port parameters of a plurality of output ports connected with the selected output channel are displayed in a given arrangement on an output channel-port setting popup screen, and the thus-displayed output port parameters are allocated to controls of corresponding channel strips. Such arrangements allow parameter setting operation to be readily performed for each of the output ports.

A wireless media player and a related system and methodology are disclosed. One aspect of the wireless media player system pertains to a virtual connector system, apparatus, and method for the automatic establishment of wireless connectivity with other electronic devices. In one embodiment, the media player device employs the use of integrated Radio Frequency Identification (RFID) technology to exchange communication settings, media capability, and other parameters with an external device that also has integrated RFID technology. The automatic exchange of settings and other information via a proximity-based RFID data exchange allows a media player to quickly establish a secure communication link with another device via a commonly supported wireless protocol such as Ultra Wideband (UWB) or Bluetooth. Another aspect of the media player system pertains to a method of using the captured media capability of the connecting device to customize certain menu options and software parameters in the media player.

A system for providing an accumulated phase to an interpolator of a read channel, the interpolator configured to provide a digital clock signal. A frequency accumulator is configured to generate a frequency offset based on a difference between the digital clock signal and a desired clock signal. A zero phase start module is configured to, during a zero phase start, output an incremental phase jump. A phase accumulator is configured to generate the accumulated phase based on the difference between the digital clock signal and the desired clock signal, and, during the zero phase start, the incremental phase jump output by the zero phase start module, or the frequency offset generated by the frequency accumulator or a predetermined frequency offset.

An apparatus includes a write element configured to apply a magnetic field to write data on a portion of a heat-assisted magnetic recording media in response to an energizing current. An energy source is configured to heat the portion of the media being magnetized by the write element. A preheat energizing current is applied to the write element during an interval before writing the data to the portion of the media. The preheat energizing current does not cause data to be written to the media and brings at least one of the write element and driver circuitry into thermal equilibrium prior to writing the data on the portion.

A plasmon generator (PG) is disclosed with a laminated structure of non-planar X and Y layers formed between a waveguide and write pole. Each X layer is made of a noble metal such as Au while each Y layer is a non-noble metal or dielectric material to improve durability. As a result, the PG has a peg portion at an air bearing surface with improved reliability compared with pegs made entirely of a noble metal. Non-planarity of X and Y layers improves diffusion of Y material between X grains thereby minimizing X grain growth to enhance thermal stability. The laminated PG is formed by a process sequence that involves forming and filling a cavity, and concludes with a chemical mechanical polish process to form a planar top PG surface that faces a write pole leading side.

Aspects of the disclosure provide a sync mark detector. The sync mark detector includes a first unit configured to decay over time a value indicating a length of a bit format, a second unit configured to compare the decayed value with a detected length of the bit format to determine a new length, and a third unit configured to detect a sync mark based on the detected length and the new length.

According to one embodiment, a multilayer optical recording medium including a substrate, a guide layer group that is provided on the substrate and has guide layers in which positional information in a radial direction is recorded, and a recording layer group that is provided on the substrate and has recording layers in which information can be recorded. In the recording layer group, positional information of the recording layers associated with the positional information recorded in the guide layers and control information of the optical device where reflected light volumes of the laser beams on the guide layers and the recording layers become maximum at the positions in the radial direction are recorded at the positions in the radial direction of the recording layers.

This invention is provides a means of playing LP records with minimal distortion. Low distortion is achieved by eliminating tracking error normally associated with pickup cartridges mounted to pivoting tone arms. This invention discloses a tone arm that constrains the motion of the stylus to straight radial path, mimicking the cutting path of the record lathe, supported on parallel rails by free rolling spherical bearings. Unlike many previous linear tracking tone arms, this invention does not rely on air pressure or servo motor mechanisms. The use of free rolling bearings or axles between parallel tracks fashioned from rails, rods or tubes, eliminates all sources of lateral friction other than pure static and rolling friction of the balls on the rails, rods or tubes. In the preferred embodiment, the fixed rods or tubes are driven synchronously, thereby eliminating static friction of the supporting rolling balls. Friction is further reduced using magnetic or buoyant support of the tone arm to reduce bearing load to that amount minimally sufficient to maintain full contact between the rolling balls and the upper and lower rods.

An optical disc having a region with pre-recorded data and a recordable region, a method of fabricating the disc, a stamper for forming a disc master, and a recording device for use with the disc are disclosed. Data recorded in the recordable region may be used for activation of the disc, providing unique identification or enhancing program content on the disc.

A wireless media player and a related system and methodology are disclosed. One aspect of the wireless media player system pertains to a virtual connector system, apparatus, and method for the automatic establishment of wireless connectivity with other electronic devices. In one embodiment, the media player device employs the use of integrated Radio Frequency Identification (RFID) technology to exchange communication settings, media capability, and other parameters with an external device that also has integrated RFID technology. The automatic exchange of settings and other information via a proximity-based RFID data exchange allows a media player to quickly establish a secure communication link with another device via a commonly supported wireless protocol such as Ultra Wideband (UWB) or Bluetooth. Another aspect of the media player system pertains to a method of using the captured media capability of the connecting device to customize certain menu options and software parameters in the media player.

An apparatus for compensating for pixel distortion while reproducing hologram data includes an extraction unit, a determination and calculation unit, a table, and a compensation unit. The extraction unit extracts a reproduced data image from a reproduced image frame including the reproduced data image and borders. The determination and calculation unit determines position values of edges of the extracted reproduced data image, and calculates average magnification error values of pixels within line data from position values of start and end point pixels thereof, which are based on the determined position values of the edges. The table stores misalignment compensation values for the pixels within the line data, wherein the misalignment compensation values correspond to predetermined references for average magnification error values. The compensation unit compensates for pixel positions in the extracted reproduced data image using the misalignment compensation values that correspond to the calculated average magnification error values.

A method of storing data includes providing a write signal for a write head of a hard disk drive, generating a transition pulse signal derived from the write signal using a transition pulse generator, and generating a logic signal to drive a thermal source associated with the write head of the hard disk drive. The logic signal includes the logical summation of a cyclical base pulse signal and the transition pulse signal.

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a laser configured to heat the disk while writing data to the disk. A temperature is measured, and a first input power is generated based on a first function of the measured temperature, wherein the first function compensates for a temperature dependent output power of the laser. A second input power is generated based on a second function of the measured temperature, wherein the second function compensates for a temperature dependent coercivity of the disk. The first input power is combined with the second input power to generate a write power applied to the laser while writing data to the disk.

The present invention relates to a plasmon generator, in which a surface plasmon is excited by application of light. The plasmon generator extends along one direction. The plasmon generator includes a first end surface that is positioned on one end in the one direction and at which near-field light is generated along with the excitation of the plasmon; and a second cross section that is substantially parallel to the first end surface and is away from the first end surface. The first end surface has a polygonal shape that does not have a substantially acute inner angle. The second cross section has an upper part that has a shape substantially the same as or similar to that of the first end surface and a flare shaped lower part that is connected to the upper part and has a width that increases as it is far from the upper part.

In a heat-assisted magnetic recording hard disk drive, one or more thermally conductive features are incorporated to assist with dissipation of heat from a laser module that comprises a laser and a submount. The submount may be coupled to the slider with solder covering a wider adhesive area for enhanced conduction of heat away from the laser module and to the slider, one or both of the submount and the laser may include a surface coating that increases the thermal radiation of the corresponding component, and/or one or both of the submount and the laser may include fins configured to transfer heat from the corresponding component. Further, a HAMR HGA may be configured such that the submount is coupled directly to the suspension flexure using a thermally conductive material, for conduction of heat away from the laser module and to the flexure.

A mark having a length nT (n being an integer equal to or greater than 3 and T being a clock period) is formed by modulating irradiation laser power with three values of recording power Pw, erase power Pe, and bias power Pb (Pw>Pe>Pb). Constant strength periods (At) of the recording power Pw are set as AtT, A1T, . . . , and AmT and constant strength periods (B) of the bias power Pb are set as BtT, B1T, . . . , BmT, and CT (C=−1 to 3). The application of laser is divided into pulses in order of AtT, BtT, A1T, B1T, . . . , AmT, BmT, and CT (m=(n−k)/2, k=3 (if n is an odd number), or k=4 (if n is an even number)). (Here, the constant strength period of the recording power Pw for n=3, n=4, n≧5 (odd number), and n≧6 (even number) is set as At3, At4, Atod, and Atev, the constant strength period of the bias power Pb for n=3, n=4, n≧5 (odd number), and n≧6 (even number) is set as Bt3, Bt4, Btod, and Btev, and then, At3+Bt3=Atod+Btod=Am+Bm=2T and At4+Bt4=Atev+Btev=3T).

In an optical information recording device and optical information recording method for angularly multiplexing and recording data on pages on the same recording region on a hologram disk, data on each page is sequentially generated by sequentially dividing input data in predetermined units, the pages to be recorded on the same recording region are divided into page groups so that pages to be recorded adjacently by the angular multiplexing may not belong to the same group, each page group is individually subjected to inter-page coding processing for computing an error-correcting code and adding the computed error-correcting code, and data on the pages subjected to the inter-page coding processing is angularly multiplexed and recorded on the hologram disk.