Abstract: A fly height control system comprises a measurement circuit that measures a first amplitude of a pulse, which is based on a predetermined pattern recorded on a storage medium, at a first predetermined time and second amplitudes of the pulse at respective second predetermined times. A calculation circuit estimates a distance between a head and the storage medium based on a function of the first amplitude and the second amplitudes. A head controller that controls the distance between the head and the storage medium based on the estimate.

Abstract: A method of recording data on an optical recording medium includes forming a mark or a space using a recording waveform which includes a DC record pattern, and an erase pattern that includes a multi pulse. According to the method and an apparatus using the method, the distortion of a mark can be prevented and the shape of a mark can be improved, thereby increasing recording/reproducing characteristics.

Abstract: An amplifier system with feedback current cancellation comprises an amplifier, a feedback network, first and second unity-gain buffers, a second resistance, and a current mirror. The amplifier includes an input, an output, and at least one stage. The feedback network includes a first resistance having one end that communicates with the input of the amplifier and an opposite end that communicates with the output of the amplifier. The first and second buffers each include an input and an output. The inputs of the first and second buffers communicate with the output and the input of the amplifier, respectively. The second resistance communicates with the outputs of the first and second buffers. The current mirror provides a current at the input of the amplifier that is proportional to a second current flowing through the second resistance.

Abstract: A disk storage device has a plurality of disk faces and a plurality of heads. The disk storage device protects the data on the disk face for a head before the defect of the head occurs. For each head, a table for accumulating the error generation count generated by the operation of a head is provided. And a control unit predicts the defect of one head based on the accumulated error generation count, reads data on the corresponding disk face by the head of which the defect was predicted, and writes the read data to another corresponding disk face by another head. Since the defect of a head can be predicted, the data can be protected in advance.

Abstract: An optical pickup device is applied to DVD recorders and includes a beam expander unit. A drive coil wound around a lens holder within the beam expander unit, is located in a magnetic field formed by a magnet. When an electric current is passed through the drive coil, the drive coil moves an expander second lens in a direction of an optical axis, receiving a force based on interaction between the electric current and the magnetic field. This changes a distance between an expander first lens and the expander second lens, and thus light emitted from the beam expander unit toward an object lens becomes diffused light or converged light. Consequently, the objective lens generates a spherical aberration in a reverse direction of a spherical aberration that has occurred owing to a deviation of a cover layer in film thickness from a reference value, which cancels the latter spherical aberration.

Abstract: An optical disk apparatus including a waiting position determining circuit which detects physical properties of each region in an optical disk after recording or reproducing processing is finished and decides a waiting position of an optical head according to the detection, and various kinds of control mechanisms which controls a position of the optical head according to the decided waiting position in order to move the optical head, is provided. By making the optical head wait at a position before two or more tracks in an unrecorded region, the recording processing can be resumed stably and surely and the recording processing can be preferentially performed in the remaining unrecorded region.

Abstract: A liquid crystal device, and a method and an apparatus for driving the same in which the refractive index of the liquid crystal device is adjusted using a simple driving method and apparatus, which is advantageous in that the cost is reduced, are provided. A liquid crystal device (10) includes a first transparent substrate (1002) and a second transparent substrate (1004) that face each other, a liquid crystal (1014) filled between the first and second transparent substrates (1002, 1004), a first transparent electrode (1006) formed on a surface of the first transparent substrate (1002) that faces the second transparent substrate (1004), and a second transparent electrode (1008) formed on a surface of the second transparent substrate (1004) that faces the first transparent substrate (1002). First and second driving signals (S1, S2) of square waves are applied to the first and second transparent electrodes (1002, 1004) with a time interval t (sec) therebetween.

Abstract: Data for specifying servo bands SB1 to SB5 is embedded in each servo signal S1 to S5 that is written on a plurality of servo bands SB1 to SB5 formed on a magnetic tape MT.

Abstract: An information recording method includes the steps of carrying out an experimental write on both inner-peripheral and outer-peripheral experimental writing areas, in the case of the outer-peripheral experimental writing, a constant recording power computed on the basis of the optimum recording power is used, which is estimated by the inner-peripheral experimental writing, in addition, an optical disk apparatus operates according to this information recording method, thereby removing the fluctuation factors of the disk.

Abstract: An optical disk apparatus for suppressing a Digital Sum Value (DSV) and performing Running Optimum Power Control (R-OPC). An encoding/decoding circuit inserts a synchronization information item to a head of only one synchronous frame when data are recorded on an optical disk. First, the encoding/decoding circuit inserts a synchronization information item having a polarity of either a mark or a space on the basis of a DSV. When the polarity of the first synchronization information item is a mark, the polarity of a next synchronization information item is set to a space. When the polarity of the first synchronization information is a space, the polarity of the next synchronization information is set to a mark. A system controller executes R-OPC at a timing when the synchronization information having the polarity of a mark is recorded on the optical disk.

Abstract: A method for opening/closing a disk tray of a disk drive. The method includes the steps of when a first event occurs, sending a load/unload command to the disk drive, to which the disk drive responds with a second or third event, and resends the load/unload command to the disk drive when the disk drive responds to the previous load/unload command with the second event.

Abstract: A method for calibrating a center error signal in an optical disc system, comprising the steps of (i) measuring a peak-to-peak value of the center error signal, (ii) computing a nominal peak-to-peak value of the center error signal after locking to a particular track of an optical disc, (iii) computing the nominal peak-to-peak value of the center error signal for a run-out condition, and (iv) defining a calibration gain for the current value for the center error signal.

Abstract: A detector for detecting information carried by a signal having a sawtooth-like shape. The detector includes a low-pass filter for receiving the wobble signal and filtering the wobble signal to generate a filtered signal, a comparator for comparing the wobble signal with the filtered signal and generating a compared signal, and a detecting unit for receiving the compared signal and generating a bit signal according to the duty cycle of the compared signal. The bit signal is a first value when the duty cycle of the compared signal is greater than a predetermined value, and the bit signal is a second value when the duty cycle of the compared signal is smaller than the predetermined value.

Abstract: Herein disclosed are an apparatus and method for encoding a wobble signal to be recorded on an optical disc, and an apparatus and method for decoding a wobble signal read from the optical disc. The encoding apparatus performs a minimum shift keying modulation operation for a wobble signal to be recorded as physical address information on a writable optical disc, by adjusting a first frequency f1 and second frequency f2 of the wobble signal with coherence. Therefore, a peak point of the wobble signal is formed at a point of time that the frequencies change. The decoding apparatus band pass filters an analog wobble signal read from the optical disc, converts the filtered wobble signal into a digital wobble signal, detects a peak point of the converted digital wobble signal, outputs a peak detection signal with a level transition at the detected peak point, and detects/outputs original wobble data on the basis of the outputted peak detection signal.

Abstract: A method and apparatus for controlling read-out and/or synchronization between an external magnetic field and written data during a reading operation from a magneto-optical recording medium includes generating a pulse in a reading signal in a read-out layer by copying a mark region from a storage layer to the read-out layer upon heating by a radiation power and with the aid of the external magnetic field. The waveform of the reading signal is analyzed, and the analysis result is used for correcting a phase deviation and/or for controlling a copy window size of the mark copying. Phase errors may thus be corrected for any size of the copy window. Even small changes in the copy window can be detected and corrected.

Abstract: A slot-in optical recording and/or reproducing apparatus includes a case formed with a slot and a swingable cover. The case provides a housing for adopting components of the slot-in optical recording and/or reproducing apparatus. The optical disk is drawn out of/into the slot-in optical recording and/or reproducing apparatus through the slot. The swingable cover is used to expose/block the slot to/from the exterior of the slot-in optical recording and/or reproducing apparatus.

Abstract: A method for controlling writing on a data carrier device, at least including: writing data on the data carrier device with a data writer device; obtaining a tracking error signal corresponding to a position of the data writer device with respect to a track on the data carrier device; if the tracking error signal is below a predetermined tracking error value: bringing the data writer device to a non-writing state; and if the writer device is in the non-writing state and the tracking error signal is above predetermined tracking error value: bringing the data writer device to a writing state in which the data writer device writes data to the data carrier device.

Abstract: A method of, and an apparatus for detecting a radial tilt of a disc. Phases of summed signals obtained from signals that external light-receiving units of an octant photo diode receive are compared to generate an external phase comparison signal Do. Phases of other summed signals obtained from other signals, that internal light-receiving units of the octant photo diode receive, are compared to generate the internal phase comparison signal Di. The radial tilt is detected based on the internal and external phase comparison signals Di and Do obtained when a laser beam crosses a track formed the disc. Thus, the radial tilt can be more precisely detected.

Abstract: The present invention relates to a method of maintaining an optimal writing power for various recording modes during data recording onto a recording medium. The present method checks a recording speed at a recording position, reads a write strategy set for the checked recording speed, detects a reflected level while recording data with the read write strategy, and changes a level reference for ROPC according to the detected level. Accordingly, a writing power can be kept most optimal even though a recording speed changes during data recording, thereby improving the quality of reproduced signals.

Abstract: Disclosed is a disk-like recording medium, a disk recording apparatus and a disk recording method, and a disk playback apparatus and a disk playback method. Disk ID is recorded over a circle of a burst cutting area on an optical disk. The circle is divided into n blocks, each of the blocks is divided into m frames, and ID information is recorded in each of the frames with k channel bits.