Teac Corporation

Mitsubishi Electric Corporation

Hiroyuki Onda

Akira Mashimo

Kyosuke Yoshimoto

Tetsuro Araki

Kazuhiko Nakane

Teruo Furukawa

Takuya Nagata

Koji Yamana

Minoru Ozaki

Osamu Ito

Yoshihiro Kiyose

Katsuya Enami

Minoru Minase

Yutaka Kobayashi

Junichi Kanenaga

Hidehiko Murata

Masaharu Ogawa

Hiroshi Tsuyuguchi

Yoshiaki Sakai

Kimiyuki Koyanagi

Tsutomu Morita

Yoshiki Nakajima

Hiroo Shimegi

Hiroshi Takahashi

Yoshiaki Umeda

Masasi Tanaka

Katsumi Aoyama

Toru Miura

Naotake Asano

An optical disk apparatus capable of determining the type of a loaded optical disk. In accordance with an RF signal output from a pickup, an RF processing section of the optical disk apparatus generates a focus signal (an FOK signal), which is an envelope of the RF signal, and supplies the focus signal to a DSP. In the DSP, the level of the FOK signal is compared with a threshold value, and a result of comparison is supplied to a controller. The controller determines occurrence of defocus on the basis of the comparison result. Concurrently, the controller quantitatively evaluates the level of the FOK signal by means of sequentially changing the threshold value, thereby determining the type of the optical disk on the basis of the reflectivity of the optical disk.

Optical disk apparatus which determines the type of optical disk

An optical disk device has a unit for counting data read errors from an optical disk and a unit for reducing a playback speed of an optical disk. When a number of data read errors occurring in a predetermined period of time exceeds a predetermined value the playback speed reducing unit reduces the playback speed of the optical disk. As a result, repetition of error detection and consequent reduction in playback speed with each data read command when reading defective sectors of an optical disk can be prevented and the time required for error detection and speed reduction thereby eliminated, greatly improving overall average playback speed.

Optical disk device

An optical disc apparatus prevents an occurrence of an error in the mirror signal due to a change in a reproducing speed or usage of different kinds of optical discs. A mirror circuit generates a mirror signal by comparing a level of a bottom signal with a level of a reference level signal. The bottom signal is detected from a reflection signal obtained by optically scanning the optical disc. A reference level control circuit generates a reference level control signal based on the reproducing speed. A reference level signal setting circuit sets a level of the reference level signal in accordance with the reference level control signal.

Optical disc accessing apparatus capable of preventing error in the

It is determined, according to a radial position of a pickup along a radius of a disk, whether or not to cause the pickup to jump to a different track so as to reduce a time required for reaching a target position on the disk. A reference value is used for the above-mentioned determination. The determination causes the pickup to jump to the different track when the target position on the disk is located behind the pickup, and also causes the pickup to jump to the different track when the target position on the disk is in front of the pickup and a distance to the target position is larger than the reference value. The reference value is determined to correspond to approximately one turn of the track at which the pickup is currently present. A buffer memory temporarily stores data which has been read out through said reading means. In response to an externally given first data transfer request, first requested data is read out from the buffer memory if it is present therein. The first requested data is read out from the disk if it is not present in the buffer memory. Data is further read, subsequent to the first requested data, from the disk continuously after the reading of the first requested data from the disk. The data thus further read is then stored in the buffer memory. When a second data transfer request is given during said reading the data subsequent to the first requested data, it is determined whether to further continue reading or to cause the pickup to jump to a different track so as to reach second requested data.

Disk apparatus having improved performance in reaching target position

An optical disk apparatus includes a disk servo unit which generates a servo signal based on a data signal read from an optical disk. The servo signal is supplied to a disk motor to control a rotation of the motor so that a linear velocity of the disk is kept constant when data is read from or written onto the disk. The disk servo unit is connected to the motor when the data is read from or written onto the disk, so that the servo signal is supplied to the motor, and the disk servo unit is disconnected from the motor when a pickup jumps from a present track of the disk to a destination track thereof so that the supply of the servo signal to the motor is inhibited. A velocity change signal which enables the motor to increase or decrease a rotating speed of the motor is generated depending on which one of two directions of the track jump is specified by a direction signal. A time signal which defines an estimated time of the track jump required to change an angular velocity at the present track to an angular velocity at the destination track is generated. The optical disk apparatus supplies the velocity change signal to the motor during the estimated time.

Constant linear velocity optical disk apparatus having improved

The disk drive apparatus of the present invention has an optical pickup that jumps a track to perform track jumping when a jumping voltage is impressed, and that traces a track by performing brake operation when a braking voltage is applied, and actuator that drives the optical pickup, a signal processing part that performs focus and tracking control with respect to the optical pickup, a movement time measurement part that measures the movement time when a light beam emitted from the optical pickup is moved to cross a track to a required track, a voltage control part that uses the results of measurement to generate parameters and a voltage value that is applied to the actuator, a storage part that stores voltage value that is generated by the voltage value setting part, and that after a disk is loaded, first stores data of that disk in the storage part and uses those data values according to the track jump operation.

Track jump control means for a disk apparatus

A disk apparatus comprising a controller receiving commands from a command input device and controlling an entire operation of the disk apparatus. The rotating control function is coupled to the controller for controlling the first motor. The pickupmotor control function is coupled to the controller for controlling the second motor. The pickup control function is coupled to the controller for controlling a focusing operation and a tracking operation of the pickup. And the signal processing function is coupled to the controller for processing a recording signal to be recorded on the disk-shaped recording medium and a reproduced signal read out therefrom. The controller is comprised function-stop function for determining whether or not any command is received from the command input device during a predetermined period of time in a state. The disk apparatus is maintained in a predetermined mode and for stopping predetermined function among the rotating control function, the pickup motor control function, the pickup control function, and the signal processing function when it is determined that no command is received from the command input device during the predetermined period.

Disk apparatus having a power consumption reducing mechanism

A miniaturized optical disk apparatus which performs a pull-in of a focus servo and a pull-in of a tracking servo without a position detector for detecting an optical head. If the optical head is located at a non-reflection film area and thus the focus servo cannot be performed, then the optical head is moved and the focus servo is performed again. This process is repeated until the focus servo can be achieved. In addition, if the optical head is located at a non-track area, then the optical disk is moved to a track area and then the tracking servo is performed. This process also repeated until the optical head is located over the track area. The tracking servo can be stably performed since it is performed only when the optical head is located over the track area. The present invention is applicable to the optical disk apparatus which uses a 3.5 in optical disk.

Optical disk storage which provides pull-in of focus servo and pull-in

A method for rewriting four defect management areas on an optical disk according to an ECMA standard is performed by means of deleting an old data which has been recorded on the respective defect management areas and then sequentially writing down a new data on respective defect management areas.

Method for rewriting defect management areas on optical disk according

A motor stopping apparatus detects a rotation frequency of a motor to which a load is attached, and applies break power in accordance with the rotation frequency to the motor until the motor is approximately stopped. The apparatus may be provided in a disk storage.

Method and apparatus for stopping DC motor by brake power corresponding

In an optical disk storage, the seek of an optical head is controlled so that the number of seek times cannot exceed a threshold number of times in a predetermined period or an accumulated seek period cannot exceed a threshold period in a predetermined period. Therefore, a wasteful power consumption and a rise in the internal temperature associated with the seek activity can be effectively prevented.

Optical disk storage having reduced power consumption during seeking

An optical or magneto-optical disk storage which automatically adjusts a recording/reproducing level of a number of kinds of optical or magneto-optical disks having different recording/reproducing levels to an optimum recording/reproducing level. The optical or magneto-optical disk storage has an attenuator which applies a predetermined attenuation amount to a reproduced signal reproduced from an optical or magneto-optical disk so as to attenuate the reproduced signal, or intensity adjusting means for adjusting the intensity of a laser beam used for recording and/or reproducing. The optical or magneto-optical disk storage detects an amplitude of the reproduced signal and feed-back-controls the attenuation amount or intensity of the laser beam in accordance with the detected amplitude.

Disk storage which automatically adjusts to optimum

For the distortionless conversion of an audio or like data signal from analog to digital form as by pulse code modulation, the input data signal is time division multiplexed with an analog dither (white noise) signal to provide a multiplex signal composed of the analog dither signal and an analog data/dither signal, the latter being an addition of the analog data and dither signals. Then the multiplex signal is converted from analog to digital form by one and the same analog to digital converter. The subsequent removal of the digital dither component from the digital data/dither signal provides a digital data signal as a replica of the input analog data signal. The use of the same converter for the conversion of both dither signal and data/dither signal from analog to digital form makes possible the maximum possible removal of the dither from the digital data/dither signal.

Analog to digital conversion method and system with the introduction and

A digital data signal such as a digitized audio signal is time division multiplexed with a digital dither signal to provide a multiplex signal compound of the digital dither signal and a digital data/dither signal, the latter being an addition of the digital data and dither signals. Then the multiplex signal is converted from digital to analog form by one and the same digital to analog converter. The subsequent removal of the analog dither signal from the analog data/dither signal provides an analog data signal as a replica of the digital data signal. The use of the same converter for the conversion of both dither signal and data/dither signal from digital to analog form makes possible the maximum possible removal of the dither from the analog data/dither signal.

Digital to analog conversion method and system with the introduction and

A system for converting an audio or like data signal from digital to analog form, with the addition of dither (white noise) to the digital input, with or without the subsequent removal of the dither from the analog output, for the reduction of quantization noise. Included is a network of n adders, equal in number to the n bits of the coded data signal, for adding in bit parallel form the digital data signal and the digital dither signal. Generated by an analog dither generator, the dither signal is transformed by an analog to digital converter into an m bit coded digital output, m being less than n, prior to delivery to the adder network. Some, preferably all, of the m bits of the digital dither signal are each added to, for example, two different ones of the n bits of the digital data signal so that, for instance, an eight bits analog to digital converter can be used for the provision of a digital dither signal to be added to a 16 bits digital audio signal. The adder network is connected to a digital to analog converter for converting the bit parallel addition of the data and dither signals into analog form.

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Hoya, Japan

Hiroyuki Onda