Abstract: A data output buffer includes an output terminal, a buffer and a pull-down driver. The output terminal is coupled to a first end of a transmission line, the transmission line being coupled to a pull-up termination resistor at a second end. The buffer pulls up the output terminal to a first power supply voltage and pulls down the output terminal to a second power supply voltage based on an output data signal. The pull-down driver pre-emphasizes an initial stage of a pull-down driving operation of the output terminal based on the output data.

Abstract: A semiconductor memory device including a trimmed voltage generator and a method of generating a trimmed voltage in the semiconductor memory device, in which the semiconductor memory device includes a voltage trimming unit, memory cell array, and a trimming current generator. The voltage trimming unit outputs a first trimming current control signal corresponding to a difference between a predetermined internal voltage and an external voltage supplied from outside of the semiconductor memory device in a trimming mode. The memory cell array stores the first trimming current control signal in the trimming mode and outputs a second trimming current control signal corresponding to the first trimming current control signal in a normal mode. The trimming current generator outputs a trimming current corresponding to the first trimming current control signal in the trimming mode and outputs a trimming current corresponding to the second trimming current control signal in the normal mode.

Abstract: Unified voltage generation techniques for efficiently generating a plurality of operational voltages for use within an electronic device, such as a memory system (e.g., memory product) providing data storage, are disclosed. A voltage generation circuit can generate a regulated base output voltage. The voltage generation circuit can include one or more voltage output circuits that produce different operational voltages from the regulated base output voltage. According to one aspect of the invention, the voltage output circuits can be disabled when the different operational voltages are at their appropriate voltage potentials, thereby reducing power consumption by the voltage output circuits. The voltage generation circuit is therefore able to operate with improved power efficiency.

Abstract: An output driving device includes a pull-up driver for pull-up driving an output node in response to a pull-up control signal; a pull-down driver for pull-down driving the output node in response to a pull-down control signal; and a first n-type metal oxide semiconductor (NMOS) transistor for pull-up driving the output node in response to a pre-pull-up control signal.

Abstract: A voltage level translator boosts the gate voltage of a transistor, and increases the gate to source voltage, to allow operation over a wider range of supply voltages. The P/N ratio of transistors in the voltage level translator is therefore increased, and control of the flipping of nodes is dependent on gate voltages as opposed to P/N ratios.

Abstract: A data output circuit of a semiconductor memory device and an operation method thereof, in which global I/O lines are selectively used according to a selected output data width. The data output circuit includes an I/O sense amplifier unit that selectively senses and amplifies a part or all of read data received from a memory bank through a Local Input and Output (LIO) lines and outputs amplified data to a part of all of Global I/O (GIO) lines, respectively, in response to a data width selection signal, a pipeline latch unit that latches the amplified data received through a part or all of the GIO lines and outputs latched data, in response to latch control signals, and an output driver circuit unit that outputs output data in response to the latched data. The number of the output data is changed according to an output data width selected by the data width selection signal.

Abstract: A semiconductor memory device includes a high voltage generator for generating a high voltage and applying the generated high voltage to a memory unit, a converter for converting an output voltage of the high voltage generator into a digital signal, and a mode selection unit for outputting an output of the converter or an output of the memory unit through an I/O terminal selectively.

Abstract: Method and apparatus for testing for a short between a wordline being tested and a bitline in a memory device. The method includes applying a first voltage to the bitline using a first voltage source and applying a second voltage to the wordline being tested using a second voltage source. The method further includes disconnecting the wordline being tested from the second voltage source; and after disconnecting the wordline being tested from the second voltage source, activating the wordline being tested, thereby connecting the wordline being tested to a wordline power supply line. A determination is made of whether a voltage of the wordline power supply line indicates a short between the wordline being tested and the bitline. The determination is based on the voltage of the wordline power supply line relative to the first voltage and the second voltage.

Abstract: A memory array for an integrated circuit includes a plurality of memory elements includes at least one redundant memory element for exchanging with a failed memory element in the plurality of memory elements. A failing address repair register is provided, having a register for controlling enablement of a corresponding redundant memory element and compare logic for determining whether an address of a failing memory element is stored in the register.

Abstract: An integrated semiconductor memory capable of determining a chip temperature includes first control terminals for driving the integrated semiconductor memory with first control signals for performing a write access and second control terminals provided for performing a read access. The integrated semiconductor further includes a control circuit for controlling a write and read access. A temperature sensor for recording a chip temperature of the integrated semiconductor memory is connected to the control circuit. The control circuit is configured to generate a state of a third control signal at one of the first or at one of the second control terminals in a manner dependent on a temperature recorded by the temperature sensor.

Abstract: A DRAM whose operation is sped up and power consumption is reduced is provided. A pair of precharge MOSFETs for supplying a precharge voltage to a pair of input/output nodes of a CMOS sense amplifier is provided; the pair of input/output nodes are connected to a complementary bit-line pair via a selection switch MOSFET; a first equalize MOSFET is provided between the complementary bit-line pair for equalizing them; a memory cell is provided between one of the complementary bit-line pair and a word line intersecting with it; gate insulators of the selection switch MOSFETs and first equalize MOSFET are formed by first film thickness; a gate insulator of the precharge MOSFET is formed by second film thickness thinner than the first film thickness; a precharge signal corresponding to a power supply voltage is supplied to the precharge MOSFET; and an equalize signal and a selection signal corresponding to a boost voltage are supplied to the first equalize MOSFET and the selection switch MOSFET, respectively.

Abstract: A circuit provides the widest possible window for capturing data and preventing run-through in a FIFO register. The FIFO register includes two registers per I/O. Two FIFO input clocks are used, one for each FIFO register. When one FIFO clock is active, the other is automatically disabled. Initially, the circuit is reset such that one clock is active, and the other disabled. Upon receiving a valid READ command, a shift chain attached to the FICLK that is currently low begins counting the clock cycles. This eventually determines when the FICLK that is currently low can be enabled. The final enable is dependent upon the turning off the FICLK that is currently high. The FICLK that is enabled during the reset turns off a fixed delay after the falling edge of the YCLK associated with the READ command.

Abstract: A semiconductor memory device comprises a plurality of memory cells connected to a plurality of word lines grouped in word line sets. Each of the word line sets is connected to a word line enable signal generation unit which stores information indicating whether data has been written to any of the memory cells connected to the word line set. The word line enable signal generation unit controls refresh operations for memory cells connected to the word line set so that only word lines connected to memory cells that have been programmed are refreshed.

Abstract: A system and method wherein a DRAM memory device on an integrated circuit (IC) uses a control logic device to initiate a body refresh operation for maintaining a low voltage at a floating body and discourage data loss. A plurality of DRAM cells are connected to a first word line circuit and a first bit line circuit. The control logic device is coupled to the DRAM memory device and the IC for initiating the body refresh cycle. The control logic communicates with a first bit line and word line circuits and communicates with a reference word line and bit line circuits. A sense amplifier circuit and signal is provided for amplifying the voltage at the first bit line and the reference bit line (or bit line bar circuit). The body refresh cycle includes deactivating the first word line voltage while the first bit line and reference bit line voltages continue.

Abstract: A memory includes a bit cell array including a plurality of word lines and address decode circuitry having an output to provide a predecode value. The address decode circuitry includes a first plurality of transistors having a first gate oxide thickness. The memory further includes word line driver circuitry having an input coupled to the output of the address decode circuitry and a plurality of outputs, each output coupled to a corresponding word line of the plurality of word lines. The word line driver includes a second plurality of transistors having a second gate oxide thickness greater than the first gate oxide thickness. A method of operating the memory also is provided.

Abstract: The present invention provides a semiconductor memory device in which the number of write amplifiers is decreased by increasing the number of bit line pairs connected to one pair of common write data lines. Further, by decreasing the number of bit line pairs connected to one pair of common read data lines, parasitic capacitance connected to the pair of common read data lines is reduced and, accordingly, time in which the potential difference between the pair of common read data lines increases is shortened. Thus, while preventing enlargement of the chip layout area, read time can be shortened.

Abstract: The present invention provides a system and method for designing and modularly expanding multiport bitcells. A modular design approach is described that reduces the complexity of designing multiport bitcells while complying with DFM rules across various semiconductor fabrication providers. The modular design may be parsed into modules such as read port modules, write port modules, and pull-up modules that may be easily interconnected to build a multiport bitcell. These modules may also be independently sized and assembled to achieve desired read margins, write margins, static noise margins as well as read access times and write times.

Abstract: Embodiments of the present invention provide systems and methods for deriving a source signature for an array of seismic sources for marine seismic analysis, wherein the systems and methods include factors for determining the source signature taking into consideration both sea-surface and sea-floor reflections of signals produced by the seismic sources. In certain aspects, reflection coefficients of the sea-surface and the sea-floor and relative lengths of paths between a seismic source image and a detector are applied to a series of simultaneous equations that are solved using measurements of the pressure field produced by the array at a plurality of known locations to determine individual source signatures for each seismic source in the array and these individual source signatures may then be superposed to provide a source signature for the array that accounts for sea-floor reflections of outputs from the seismic sources.

Abstract: A visual indicating device comprising two or more discs (1, 2) each disc having a radial discontinuity (3, 4) to thereby form a surface of which the plane progresses in a helical manner, said discs being superposed and interleaved and lying in mutually parallel helical planes, each disc being independently rotatable about a common axis (5, 6) by drive means (20, 22, 30, 31) adapted to selectively rotate one (1) or other (2) of the discs, whereby the discs, when viewedaxially face on, display overlapping visually contrasting segments having an area or position representative of the relative positions of rotation of the discs and representing a value of a parameter to be displayed by the device.

Abstract: The timepiece includes a motor which drives at least one hand via a gear reduction train (8, 9, 10, 11, 12, 13), and means (22) for detecting at least one angular reference position of an intermediate wheel (9) forming part of the gear reduction train. The detection means are provided for supplying a signal having a first value when the intermediate wheel is occupying the angular reference position (?) and for supplying a signal having a second value when the intermediate wheel (9) is occupying a second angular position (?). The timepiece further includes identification (32) and comparison (33) means for determining, on the basis of the signals supplied by the detection means (22), at least once per revolution of the intermediate wheel (9), whether the real position of the intermediate wheel actually corresponds to the theoretical position thereof.

Abstract: An apparatus and method for retrieving data related to a data cartridge contained in a multi-plane media storage system. One or more data retrieval devices are attached to the cartridge access device. A transponder is attached to the data cartridge for storing the related data, and at least one reader attached to a cartridge access device of the media storage system is positionable adjacent the data cartridge for reading the related data from the transponder. A scanner adapted to scan bar code indicia on the data cartridges may also be attached to the cartridge access device at the opposite end from the reader.

Abstract: An optical pickup apparatus including a swing arm pivotably installed in a tracking direction with respect to a disc, and an optical pickup unit supported by the swing arm and driven in a focusing direction, wherein the optical pickup unit includes a laser diode, an objective lens to focus light emitted from the laser diode on a recording surface of the disc, and a heat sink plate to dissipate heat generated from the laser diode, wherein the heat sink plate is provided close to the disc so as to be directly exposed to wind generated during rotation of the disc.

Abstract: An optical disc drive includes: a light source; a focusing section; a focus shifting section for shifting the focal point of light by changing the position of the focusing section perpendicularly to a data storage layer of a given optical disc in accordance with a control signal; a light receiving section for receiving, at multiple areas, the light reflected from the data storage layer and generating light quantity signals; a signal generating section for generating a focus error signal based on the light quantity signals; and a control section for generating the control signal responsive to the focus error signal such that the focal point is transferred to a focus controllable range. The control section generates the control signal such that the focal point is decelerated at a first acceleration and then at a second acceleration. The absolute value of the second acceleration is smaller than that of the first acceleration.

Abstract: The present invention is provides a method and apparatus for slip protection of DVD-RAM drive's seek control, comprising a slip end velocity controller, a re-seek controller, and a slip detector. Among them, the slip end velocity controller is used for providing a first control signal to direct a driver to control the slip end velocity of the optical head while seeking. The re-seek controller is capable of providing a second control signal to the seek controller for directing the seek controller to control the driver driving the optical head for re-seeking. The slip detector is used for receiving the TE signal sent from the preamplifier to determine if the optical head is slipping and to switch the input signal of the driver.

Abstract: A detection signal S1 outputted from a light reception unit (11A) of detection elements (11) formed by four-division light reception element is added to a detection signal S4 outputted from a light reception unit (11D) so as to obtain an addition signal S14 and a phase difference signal P1 indicating the phase difference between the addition signal S14 and the detection signal S1. Furthermore, a phase difference signal P4 indicating the phase difference between the addition signal S14 and the detection signal S4 is obtained. The phase difference signal P4 is subtracted from the phase difference signal P1 so as to generate a tracking error signal TE1.

Abstract: A recording method includes the steps of detecting whether unique information is recorded in a storage medium outside a predetermined area managed by a management data that manages data in a data area on a storage medium; generating unique information when in the detecting step no unique information is detected as being recorded in the storage medium; and recording the unique information when generated in the generating step to the storage medium outside the area managed by the management data.

Abstract: An optical disk drive for driving an out-of-specification disk such as a CCCD. When the out-of-specification disk, such as a CCCD (Copy-Controlled CD), is loaded in the optical disk drive, a system controller of the optical disk drive reads TOC data in a first session and TOC data in a second session. When a contradiction exists between the TOC data in the second session and the TOC data in the first session, the system controller deems the disk to be not a within-specification disk but an out-of-specification disk, thereby diminishing the number of retry operations for reading data or a retry time, and reading data by means of generating a synchronization bit SYNC through use of an internal counter.

Abstract: An apparatus and method has a capable of precisely detecting Land Pre-Pit (LPP) data recorded on an optical medium loaded into an optical drive. The apparatus includes an LPP data detecting unit that detects LPP data, from which a wobble frequency is removed, from a signal reflected from the optical medium; a wobble signal detector that detects a wobble signal from the reflected signal; and an LPP data generator that generates the LPP data recorded on the optical medium, using the detected LPP data and the detected wobble signal.

Abstract: An information storage medium having a plurality of information storage layers, each of which includes an optimal power control (OPC) area for obtaining an optimal recording condition, wherein OPC areas in odd-numbered and even-numbered information storage layers are disposed not to face each other and not to contact each other, or partially overlap each other and lock out use of the overlapped portion. Therefore, when an OPC area of one information storage layer performs OPC, this OPC does not affect another information storage layer.

Abstract: An information recording device comprising a recording unit that records recording information by applying a laser beam to an information recording medium having a first recording layer for recording recording information by being irradiated with a laser beam and a second recording layer for recording recording information by irradiating with a laser beam via the first recording layer, a calculating unit that calculates an optimum laser beam power when, by using the recording means, trial-recording trial information is recorded by irradiating the second recording layer with a laser beam via a recording-information-unrecorded recording area in the first recording layer and recording information is recorded by irradiating the second recording layer with a laser beam via a recording-information-recorded recording area in the first recording layer, and a control unit that controls the recording unit.

Abstract: A method for determining a read power of a laser beam includes a step of setting a power of a laser beam to a recommended recording power Pw? and forming a recording mark train including at least one of a recording mark having a length shorter than a resolution limit and a blank region having a length shorter than the resolution limit in an optical recording disc, thereby recording test data therein. The method also includes a step of setting the power of the laser beam to a recommended read power Pr? and reproducing the test data recorded in the optical recording disc, a step of judging whether or not signal characteristics of a reproduced signal obtained by reproducing the test data satisfies reference conditions, and determining an optimum read power of the laser beam based on the result of the judgment.

Abstract: An open-loop test procedure under high rotating speed is entered to compute a first TE crossing track number. The first TE crossing track number greater than a first threshold indicates an unbalanced disc and results in a low-speed reading procedure. On the other hand, the first TE crossing track number less than a second threshold value that is less than the first threshold value indicates a normal disc and results in a high-speed reading procedure. When the first TE crossing track number lies between the first and second threshold values, another open-loop test procedure under low rotating speed is entered to compute a second TE crossing track number. A low-speed reading procedure is performed when the second TE crossing track number is greater than a third threshold value, and a high-speed reading procedure is performed when the second TE crossing track number is less than the third threshold value.

Abstract: In an information recording medium recording method, recording is interrupted, in recording on an information recording medium, when a predetermined interruption condition is met. A signal recorded in a recorded area is played back and a recording signal playback waveform signal is obtained. Error information indicating an error between a reference waveform signal derived by partial response equalization of a data string and the recording signal playback waveform signal is obtained. A recording condition is corrected on the basis of the error information. A recording/playback apparatus and information recording medium are also disclosed.

Abstract: An optical disk drive capable of detecting a surface deviation of a disk during a very short period includes an analog-to-digital converter (ADC) converting a focus error signal output from a pickup into digital data, and a central processing unit (CPU) writing an output of the ADC to a memory during one rotation of a motor according to a timing of a pulse signal output from a spindle motor. After that, the CPU reads data written to the memory and obtains a sine curve that minimizes the sum of squares of errors among data by a least square method. The CPU obtains a peak-to-peak value of the obtained sine curve and compares the peak-to-peak value to a predetermined threshold value, thereby determining the existence of the surface deviation of the disk.

Abstract: The present invention enhances the usability of a write-once recording medium having a plurality of recording layers. The write-once recording medium has a plurality of recording layers each including a regular recording reproduction area, an alternate area, a first alternate-address management information area and a second alternate-address management information area (a TDMA). In addition, written unwritten state indication information (a space bitmap) is recorded therein. Typically, the written unwritten state indication information is recorded in the second alternate-address management information area. By additionally recording alternate-address management information related to an alternate-address process in the second alternate-address management information area, the second alternate-address management information area can be used as an area for implementing renewal of the alternate-address management information.

Abstract: There is provided an information recording device for recording record information onto an information recording medium having a plurality of recording layers. The information recording device includes: write elements capable of writing record information into the recording layers; control elements for controlling the write elements to write first boundary information or second boundary information (107a-0) having a smaller recording capacity than the first boundary information at the end of record information recorded in one of the recording layers; and detection elements for detecting an empty capacity of the data area in that recording layer. The control elements controls the write elements to write the first boundary information at the end if the empty capacity is equal to or greater than a first threshold value and the second boundary information at the end if the detected empty capacity is smaller than the first threshold value.

Abstract: The present invention makes it possible to set an operating condition enabling the best recording characteristic to be obtained for any kind of recording media, even in the case where the recording medium is combined with any kind of drive devices. According to the present invention, even in the case where a unknown and new kind of recording medium is loaded into the drive device, a piece of first operating condition information for an optical system suitable for a combination of the drive device and the new kind of recording media is read from a specific read only area provided for the recording medium, and an operating condition enabling the best operating characteristic to be obtained is set by using the first operating condition information, as a result of which even in the case where any kind of recording medium and any kind of drive device are combined, the operating condition for enabling the best recording characteristic to be obtained for the recording medium, can be set in the drive device.

Abstract: A method for adjusting a focus bias in an optical disc drive comprises the steps of: rotationally driving an optical disc in a state that only focus servo is engaged without engaging tracking servo; driving an actuator of an optical pick-up so that a laser beam projected from the optical pick-up is moved in a tracking direction to obtain an HF signal; and determining a focus bias by which a proper focusing point can be obtained based on the HF signal. The driving of the actuator is carried out by supplying an actuator drive control signal to a tracking actuator of the optical pick-up in a state that tracking servo is not engaged.

Abstract: A read-only information storage medium having one or more recording layers and a method and apparatus reading/reproducing data, the read-only information storage medium having one or more recording layers, each layer containing a lead-in area, a user data area, and a lead-out area. The locations of the lead-in and lead-out areas may be fixed, and when an amount of user data recorded on the storage medium is less than a full capacity of the storage medium, data other than the user data is recorded on a space remaining after the user data has been recorded.

Abstract: An information reproducing method using PRML technology which provides asymmetry compensation and also assures media interchangeability. To compensate for asymmetry, target levels are basically adapted to readout signals and either restriction type (1) (time reversal and level reversal symmetry) or restriction type (2) (time reversal symmetry) is imposed between target levels. As a consequence, asymmetry compensation is made regardless of a readout signal distortion such as mark shift which might deteriorate media interchangeability.

Abstract: A recordable optical information recording medium having an address t for each sector, comprises: an area A1 starting from an address t1 to which access is made only when a recording apparatus performs recording operation; an area A2 starting from an address t2 to which access is made either when the recording apparatus performs the recording operation or when the recording apparatus performs reproducing operation; and an area A3 starting from an address t3 to which access is made either when either the recording apparatus or a reproducing apparatus performs recording or when either the recording apparatus or the reproducing apparatus performs reproducing. The addresses t are set consecutively with respect to a physical arrangement of the sectors in each of the areas A2 and A3, and the area A1 has at least one inconsecutive part at which the addresses t are not consecutive with respect to the physical arrangement of the sectors.

Abstract: An optical pickup apparatus for conducting recording and/or reproducing information of an optical information recording medium, comprises a light source; a converging optical system having an objective lens; and a photo-detector. The converging optical system comprises a plastic lens and a spherical aberration deviation correcting element to correct deviation of a spherical aberration of the converging optical system. A numerical aperature of the objective lens at an image-side is 0.65 or more.

Abstract: An objective optical element for use in an optical pickup apparatus comprises a first optical surface including a first diffractive structure which comprises a plurality of concentric ring-shaped diffractive zones having a center on the optical axis and stepped surfaces arranged to be almost parallel to the optical axis and connecting respective neighboring ring-shaped diffractive zones; and a second optical surface including a second diffractive structure which comprises a plurality of concentric ring-shaped diffractive zones having a center on the optical axis and stepped surfaces arranged to be almost parallel to the optical axis and connecting respective neighboring ring-shaped diffractive zones. The stepped surfaces of the first diffractive structure are arranged to face an optical axis side, and the stepped surfaces of the second diffractive structure are arranged to face an opposite side of the optical axis side.

Abstract: An optical pickup device includes an objective lens (2), with a numerical aperture (NA) being not less than 1, having a solid immersion lens (1) which is made up by a spherical portion (1a) and a flat portion (1b) parallel to a surface (101a) of an optical disc (101). The component of the reflected light from the optical disc in the polarized state perpendicular to the polarized state of the reflected light which prevails when the distance between the surface of the optical disc and the flat portion of the solid immersion lens is zero is detected. The so detected light intensity is associated with the distance between the optical disc surface and the solid immersion lens to accurately detect the minute gap between the optical disc and the solid immersion lens.

Abstract: A magnetic recording device is provided according to the present invention for magnetic recording on a recording medium. The magnetic recording device includes a planar waveguide having a propagation axis. The planar waveguide allows light received thereby to propagate along the propagation axis. The magnetic recording device further includes a magnetic pole having a yoke disposed adjacent the planar waveguide and a pole tip extending into the planar waveguide along the propagation axis. By extending the pole tip into, and incorporating it with, the planar waveguide, the light propagating through the planar waveguide and a magnetic flux flowing through the magnetic pole are co-locatable on a recording medium disposed adjacent the magnetic recording device.

Abstract: An optical pickup device comprises a photodetector for receiving laser light reflected from a disc and a housing in which the photodetector is housed, and the photodetector is directly attached to the housing. Through the use of the optical pickup device, occurrence of positional deviation of the photodetector can be suppressed, even under greatly changing temperatures.

Abstract: A copper frame plate (2) has a central frame plate (2a) and a pair of side frame plates (2c) bent from both ends of the central frame plate. A flexible substrate (3) has a central substrate (3a) covering the central frame plate and bent substrates (3b) bent from the central substrate so as to cover the side frame plates. An optical element (4) is mounted on the central frame plate. A plurality of internal wiring terminals (9) connected to the optical element are disposed on the central substrate and arranged in the width direction (W) along which the pair of side frame plates are opposed to each other. A plurality of external wiring terminals (11) used for connection to external equipment are disposed on the bent substrates and arranged in the length direction (L) orthogonal to the width direction.

Abstract: On an information recording medium, an entire stream including a plurality of portion streams, each of which is provided with content information including still picture information, is multiplexed-and-recorded by a unit of packet. The information recording medium is provided with a file for storing object data, which is provided with a plurality of packets, each of which stores therein a piece of the content information. The information recording medium is further provided with a file for storing information which defines a reproduction sequence of the object data. The object data includes packets, each packet storing therein a piece of respective one of still picture information sets, the still picture information set including still picture information and control information thereof. A display control to the still picture information included in one still picture information set is described by the control information included in another still picture information set.

Abstract: An information storage medium according to an embodiment of this invention includes a management area for recording management information, and a data area for recording content data. The content data recorded in the data area contains a plurality of object data, each object data contains a plurality of data units, each data unit contains a plurality of packs, each pack contains at least one packet, the packet contains at least one transport stream packet, the management information recorded in the management area contains program chain information which manages the playback order of data contained in the object data, the program chain information contains cell information, and the cell information contains information that specifies an object to be played back.

Abstract: To improve the sync code detection reliability while simplifying the sync code position detection process, when a first pattern as a combination of three successive sync codes is compared with a second pattern in which the allocation of sync codes is shifted by one code from the first pattern, two or more sync codes are changed.