Abstract: A device for and method of reducing intersymbol interference (ISI) and/or crosstalk is disclosed. The ISI and crosstalk reducing device includes an optical detector which divides an optical signal reflected from an optical disk into central and peripheral parts in the tangential direction of the optical disk, and a correcting unit for controlling the gain value of a peripheral detection signal detected by the optical detector and adding the gain-controlled detection signal and a central detection signal to each other to provide an ISI corrected signal. Instead of using the existing waveform equalizer, the device uses a multiple-divided detection signal output from the optical detector to thereby obtain a jitter value of the same level as that obtained when the waveform equalizer is used. Further, in HD-DVD system requiring high density recording, it is possible to reduce crosstalk and ISI at the same time even when the high density recording causes crosstalk or interference between neighboring tracks.

Abstract: The present invention includes a playback means for playing back data on a disk; an audio output unit for outputting audio data as an audio signal to the outside when the audio data is played back by the playback unit; an audio level manipulation unit for manipulating the output level of the audio signal outputted from the audio output unit; a detection unit for detecting a set value of the audio level manipulation unit; and a rotation speed control unit for controlling the rotation speed of the disk which is played back by the playback unit on the basis of the set value detected by the detection unit only when no audio signal is outputted from the audio output unit. In this disk playback device, less influence is exerted upon the operation of the drive even when an erroneous operation is performed and the user can arbitrarily change the disk rotation speed by a simple operation without adding a new operation unit.

Abstract: The present invention relates to an optical disk apparatus which performs information recording or reproduction into/from an optical disk, and provides an optical disk apparatus which makes the amount of optical pickup movement performed before adjustment of a track error signal suited and enables reduction of a start-up time. When a track error signal is subjected to adjustment, it is previously detected in a signal amplitude detecting circuit 17 whether an optical pickup 1 is located in an area where a required track on an optical disk medium 2 exists or not, and a micro processing unit 6 executes the procedure which uses only the necessary but minimum moving time, even when the optical pickup is required to be moved.

Abstract: In a digital recorded data reproduction which applies PRML signal processing, it is an object to enhance a reproduction signal quality and a playability for an abnormal signal by an offset correction and a phase-interpolation-type digital phase-locked loop. A prescribed frequency band of a reproduction signal is emphasized by a waveform equalizing unit 2, and its output signal is sampled by an asynchronous clock at an analog/digital converter 3. After a sampling signal is subjected to the offset correction, PR equalization is performed by a transversal filter 6 and a tap weighting factor control unit 8 which applies LMS algorithm, and a signal of a regular sampling phase is reproduced from its output signal by a high-order interpolation filter 7 employing a digital phase-locked loop 11. The reproduced signal in a regular phase is demodulated by a maximum likelihood decoder 12, thereby to reproduce digital data recorded on a medium.

Abstract: A collection management system, or virtual jukebox, is provided for a collection of recordings that is independent of the physical media upon which the material is recorded. The system forms a part of a network that includes storage media and playback devices, and provides an easy to use system for collection cataloging, archiving, and retrieval. In a preferred embodiment, a collection management system resides on a consumer electronic (CE) device, or a personal or home computer (PC), and the collection includes recordings that are stored on one or more hard drives associated with the CE device or the PC. The collection management system includes a user interface that facilitates the retrieval of recordings for playback from one or more storage devices, based on an individual selection of genre, author, and so on.

Abstract: A pre-pit detection unit having pre-pit detection circuits (600 and 700) respectively corresponding to beam intensity in mark and space periods that are provided in parallel on the output side of a push-pull circuit (500) for generating a pre-data signal. The pre-pit detection unit finally outputs the OR of the outputs of both pre-pit detection circuits as a pre-pit detection signal (l). An AGC circuit (601 and 701) for making the maximum amplitude of a radial push-pull signal (d) obtainable from said push-pull circuit coincide with a reference value is provided in the preceding stages of pre-pit detecting comparators (606 and 706) in the respective pre-pit detection circuits.

Abstract: A nonlinearity compensation circuit is disclosed which includes an inverse hyperbolic function generation circuit for converting differential currents corresponding to input signals in+ and in− into differential voltages which increase in proportion to an inverse hyperbolic function, an offset provision circuit for providing an offset corresponding to control signals c+ and c− to the differential voltages outputted from the inverse hyperbolic function generation circuit and a hyperbolic function generation circuit for converting the differential voltages to which the offset has been provided by the offset provision circuit into signals which increase in proportion to a hyperbolic function and outputting the resulting signals as output signals out+ and out−. Consequently, compensation for the nonlinearity such as second order distortion can be performed for the read signal from a recording medium.

Abstract: An optical disc player, and more particularly, an apparatus controlling a mirror signal independently of variations of the quantity of light in a laser received by a pickup or the reflectivity of a disc, and a method thereof. The apparatus includes an envelope detector detecting an envelope of a signal which is reflected from an optical disc, a center voltage outputting unit outputting a center voltage of the envelope, a comparator outputting the optimum mirror signal by comparing the envelope with the center voltage using a predetermined mirror controlling signal and a mirror signal controller outputting a predetermined mirror controlling signal to the comparator, until the mirror signal output from the comparator reaches a predetermined level compared to a fixed mirror signal.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus.

Abstract: A data recording system employs parallel iterative decoding of soft output samples representing encoded data read from a storage medium. The iterative decoder reads packets of data from a sector of the medium, each packet containing soft output samples representing data encoded with a concatenated code formed from N component codes, N a positive integer. The iterative decoder employs I decoding iterations, I a positive integer. Each packet has a length substantially equal to the sector length divided by N. For an exemplary magnetic recording system, encoded data read from a sector of a magnetic medium is partitioned into N packets of length 4096/N. The first packet is passed to the first component code decoder of a parallel iterative decoder. When the second packet is ready to be passed to the first component code decoder, the decoded output values of the first packet in the first decoder are passed to the second component code decoder. The second packet is then applied to the first component code decoder.

Abstract: A tracking error balance adjustment circuit, and a current control circuit used for a variable gain RF amplifier automatically controlled to output a signal having a predetermined amplitude. The tracking error balance adjustment circuit comprises two separate gain adjusting circuits, each having variable attenuation circuit having first gm amplifier of variable gm type, a second gm amplifier of variable gm type connected to the variable attenuation circuit, and an output circuit connected to the second gm amplifier, comprising an operational amplifier circuit having feedback resistor, wherein the first and second gm amplifiers are differentially controlled commonly by a control current.

Abstract: A device suitable for manufacturing an optical registration carrier, such as a master plate, which device comprises a support for said optical registration carrier, at least a first and a second light source, wherein the wavelengths of the light from said first and said second light source are different from each other, as well as an objective disposed between said light sources and said support, which is movable with respect to said light sources. A correction lens is disposed between the first light source and the objective, which correction lens can be moved jointly with the objective. The focal points of the two light sources at least substantially coincide with various movements of the objective and the correction lens with respect to the light source.

Abstract: An object of the present invention is to remove a laser beam source noise in an optical disc device.

Abstract: A method for controlling the position of an optical beam incident on a track of a rotationally mobile carrier of information, such as a disc, includes picking up a beam reflected by the disc using an optical pick-up and determining a positioning error of the beam with respect to the track. The pick-up may include several photodetectors each providing an elementary signal, and the positioning error may be determined from the elementary signals. More precisely, from the elementary signals two sampled secondary signals whose mutual time gap is representative of the positioning error of the beam with respect to the track may be formulated. Furthermore, successive current values of the mutual time gap may be determined at the sampling frequency by searching at the sampling frequency for a successive current maximum of the cross-correlation function between the two sampled secondary signals. The present invention may be particularly applicable to multifunction digital disc (e.g., DVD) readers, for example.

Abstract: Disclosed is a pick-up head controller for optical disk drives, structured particularly for optimal actuation characteristics of a pick-up head of optical disk drives. A framework, composed of a high-frequency digital controller and a low-frequency digital controller, accomplishing different order types of controllers required by optical head systems, is provided based upon the sampling rate dependence of response of digital controllers. Experimental results shows excellent performance in optical systems that high performance, low cost and easy designing can be achieved.

Abstract: A reproducing apparatus and a signal processing apparatus each having a filter for eliminating cross modulation distortion when cross modulation noise is caused by poor compatibility with an amplifier or a speaker connected to a reproducing apparatus for reproducing a digital signal composed of quantization one-bit data having high-frequency band.

Abstract: A method and apparatus for adjusting equalization characteristics of signals reproduced from an optical disk rotating at a constant angular velocity. The method according to the present invention includes measuring the linear velocity of an arbitrary track on a rotating optical disk medium and adjusting equalization characteristics of signals reproduced from the track based on the measured linear velocity. The method provides high fidelity data reproduction by allowing fine adjustment of equalization characteristics and general applicability, by exploiting signals recorded on the particular optical disk medium read.

Abstract: A device is provided for calculating mutual phase shift of first and second incident signals. The device includes a first pair of blocks associated with the first incident signal, a second pair of blocks associated with the second incident signal, checking circuit, and post-processing circuit. Each of the blocks has storage elements for storing a predetermined set of samples of the corresponding incident signal. In the presence of minimum samples or maximum samples of both incident signals, the checking circuit stores a first set of samples relating to the first incident signal in one of the blocks of the first pair and a first set of samples relating to the second incident signal in the counterpart block of the second pair, and then stores the following sets of samples of each incident signal alternately in the two blocks of each pair. The checking circuit delivers a block validation signal when a set of samples has been completely stored in the storage elements of one of the blocks.

Abstract: Like a rewritable optical disk, a read-only optical disk interchangeable with a rewritable optical disk has a plurality of sector fields of a first specific length. Each of the second sector fields has a header field of a second specific length and, following the second header field, a recording field of a third specific length as in the rewritable optical disk. Each of the second recording fields has a read-only second user data recording field of a fourth specific length in a specific position as in the rewritable optical disk.

Abstract: An apparatus of forming an evaluation signal used in adjusting focus bias and adjusting skew of a disk drive in which phase error information between a phase of a read data signal and a phase of a clock signal formed in synchronism with the read data signal, is detected, the phase error signal is converted into an analog signal and is outputted as an evaluation signal having a signal level in accordance with the phase error amount and the evaluation signal is inputted after A/D conversion to a portion for carrying out signal quality evaluation by using the evaluation signal whereby pertinent signal evaluation can be carried out by a simple constitution.

Abstract: An optical information reproducing apparatus and an optical information reproducing method are capable of restraining the variation of laser power by always detecting a constant amplitude of RF signal, even if there is a irregularity of asymmetry. In the optical information reproducing apparatus for reproducing an information signal recorded on a disk (8) by irradiating thereon a laser light modulated by an information signal, during reproduction, the control amount (S4) of the power control circuit 11 for controlling the power of the laser light to an optimum value is made the value based on the amplitude level VP−, VP+ of the reproduced information signal.

Abstract: A balance gain tuning apparatus including a first amplifying part amplifying one of signals output from a optical pickup to a fixed gain; a second amplifying part amplifying another signal of the signals output from the optical pickup to a tunable gain; a subtracting part producing a difference of an output of the first amplifying part and that of the second amplifying part; and a servo control part tuning the gain of the second amplifying part in response to an output of the subtracting part.

Abstract: Some of various multisignal (a plurality of signals except zero in the conventional binary system ) which are a variety of memories employed as signals instead of a single memory in the binary system are recorded in a medium for multisignal, by moving a recorder for multisignal to a determined position. An extractor is moved to a determined position to extract a part of the multisignal which have been recorded at that position in advance. When any change has to be made to the recorded multisignal, the change is made by the recorder. The multisignal can be used in two or more pairs as well. When processing a signal in the multisignal method in which various signals are used instead of 1 in the conventional binary system, the medium erases, writes, and corrects the signal with a machine which uses multisignal of light, magnetism, etc. that can be clearly discriminated from one another.

Abstract: A first pair of light-receiving cells and a second pair of light-receiving cells are diagonally arranged to constitute a quadrifid light-receiving cells. A pair of first wiring patterns are respectively connected to the first pair of light-receiving cells for leading out output signals therefrom. A pair of second wiring patterns are respectively connected to the second pair of light-receiving cells for leading out output signals therefrom. The first wiring patterns are arranged adjacent to each other, and the second wiring patterns are arranged adjacent to each other. A third wiring pattern is arranged between the first and second wiring patterns, in which a signal having a different nature from those of the output signals from the light-receiving cells.

Abstract: A waveform equalizer which can improve an S/N ratio without causing a jitter in a read signal read out from a recording medium. An amplitude level of the read signal read out from the recording medium is limited by a predetermined amplitude limitation value and, thereafter, is subjected to a filtering process.

Abstract: Method and apparatus for recovering a timing reference signal in an optical storage subsystem. The timing reference signal is recovered by passing it through a zonal bandpass filter coupled to a hard limiter, which feeds a phase locked loop that produces the reference signal.

Abstract: An amplitude detector for signals having a periodical character, recorded on a recording medium, including a first delay line and a second delay line, wherein an average maximum value of the detected signal is stored in the first delay line for each one of a predetermined number of detection instants within a detection period, and an average minimum value of the detected signal is stored in the second delay line for each one of the detection instants, means for determining an average level between the average maximum and minimum values for each detection instant on the basis of the output signals of the two delay lines, and means for comparing the current signal to be detected for a given detection instant with the average level for the detection instant so as to provide a detection signal.

Abstract: A signal compensating apparatus is an apparatus for compensating a control signal which is generated on the basis of a light beam reflected by an optical recording medium and which includes information with respect to a relationship between a spot of the light beam and a track of the optical recording medium. The signal compensating apparatus has: a detecting device for detecting a damaged part of the control signal, which is caused by a defect of the optical recording medium or an obstruction existing on an optical path of the light beam or on the optical recording medium; a replacing signal generating device for generating a replacing signal whose level gradually varies so as to connect a level of a first normal part of the control signal immediately before the damaged part with a level of a second normal part of the control signal immediately after the damage part; and a replacing device for replacing the damaged part by the replacing signal.

Abstract: A magneto-optic disk and a recording/reproduction device therefor adopt optical super-resolution to increase recording capacity. More specifically, the magneto-optic disk has an heat emitting layer (6) on a recording layer (4) and still preferably has an intermediate layer (8) between a reproduction layer (3) and the recording layer (4). The recording/reproduction device includes a circuit (33) for pulsing a laser beam to be radiated to the magneto-optic disk and still preferably includes a polarization rotating unit (50) and a polarizing filter (51) for blocking only the center of the laser beam in reproduction. The heat emitting layer (6) diffusing any heat generated by the laser beam, and the discontinuously radiated laser beam allow small recording domain. The laser beam having its center blocked forms smaller main lobe due to diffraction effect.

Abstract: A method for monitoring and adjusting a motor current in a disk data drive allows to adjust a rotation speed of a disk to be as high as possible in order to increase an overall performance of the disk data drive. It comprises measuring the value of the motor current fed to the motor for an actual value of the disk rotation speed, comparing the value of the motor current with a nominal value of motor current at the actual value of the disk rotation speed, increasing the disk rotation speed to a new actual value of the disk rotation speed if the value of the motor current is substantially equal to the nominal value of motor current.

Abstract: A central servo control system is used in an optical disc drive to control an optical pickup head. The optical at least includes a lens. The central servo control system includes a radio frequency (RF) amplifier, a sled motor, a tracking coil, and a central servo controller. The RF amplifier chip is coupled to the optical pickup head so as to receive the optical signal, which is amplified and processed so as to produce a RF data signal, a tracking error (Te) signal, and a central servo (Tcs) signal. The sled motor is used to hold the optical pickup head and move the optical pickup head to a desired position. The tracking coil located on the optical pickup head is used to move the lens to a designed position so as to allow the optical signal to be easily detected by the optical pickup head. The central servo controller receives the RF data signal, the Te signal, and the Tcs signal from the RF amplifier chip, and accordingly exports a tracking control signal to the tracking coil.

Abstract: A signal detection method of an optical pickup which reproduces information from a phase-change optical disk, such that the optical pickup includes a photodetector having four light receiving regions. The signal detection method includes the steps of receiving light reflected from the phase-change optical disk using the photodetector, and detecting, as a reproduction signal, a difference between light quantities of light incident to the ones of the light receiving regions which are located forward from an optical axis of the optical pickup along a tracking direction of the optical pickup and those of light incident to the ones of the light receiving regions which are located backward from the optical axis of the optical pickup along the tracking direction of the optical pickup.

Abstract: A tracking system for optical storage media e.g. an optical disk, comprising a matrix of four sensors receiving a beam reflected by the disk; one processing channel for each sensor signal, including means for producing a binary signal from the sensor signal, and an adjustable edge delay circuit operating on the binary signal; one adder for each pair of channels corresponding to diagonal sensors of the matrix; and a phase detector comparing the outputs of the adders.

Abstract: In disk drives incorporating the present Peak Detection Channel invention (PDC) an important feature is the ability to locate the data on a disk. Servo timing sectors for each data track are recognized by the embodiments of the invention cooperating with system electronics at start up of the disk drive system. Variation of data pulse heights, widths and shapes over a broad range are accommodated. The invention takes advantage of the fact that typical pulse shapes (e.g. Gaussian or cosine-squared) can be closely approximated near their peak by a parabolic curve.

Abstract: An optical information processing apparatus includes: an optical head for radiating a light beam onto an information storage medium and generating a reproduction signal from the light beam reflected an/or diffracted from the information storage medium, the information storage medium carrying optically readable information recorded thereon; a transportation member for causing a relative movement of the optical head with respect to the information storage medium; and a signal processing circuit for receiving the reproduction signal generated by the optical head and processing the reproduction signal.