Sony Corporation

Ryo Ando

Kazuhiko Fujiie

Tadao Yoshida

Yasuaki Maeda

Hideo Obata

Hideki Nagashima

Hirotoshi Fujisawa

Hiroshi Mukawa

Nobuhiko Ando

Takao Maruyama

Seiryu Takayama

Katsuaki Tsurushima

Takashi Ohmori

Takeshi Yamaguchi

Hirokazu Kuroda

Yayoi Mochizuki

An optical disk reproducing device has a defect-signal generating circuit including a peak-holding-signal generating circuit for generating a peak-hold signal based on an RF signal read from a recording medium, an intermediate-signal generating circuit for generating an intermediate signal based on the peak-hold signal, a signal-level adjusting circuit for generating a threshold signal based on the intermediate signal, a threshold-signal adjusting circuit for adjusting the level of the threshold signal, and a comparator for generating a defect signal based on the peak-hold signal and threshold signal. The threshold-signal adjusting circuit includes at least one of: a first adjusting circuit for raising the threshold signal in the event the peak-hold signal falls below the threshold signal due to the peak-hold signal and the threshold signal being reversed; and a second adjusting circuit for lowering the threshold signal in the event the peak-hold signal exceeds the threshold signal, due to the reversal.

Defect-signal generating circuit and optical disk reproducing device having the same

A disk drive apparatus drives, by means of a motor, a disk mounted thereon so as to reproduce signals recorded in the disk. The disk drive apparatus has an edge detecting unit for generating an edge signal XEG indicating a timing of phase switching, in accordance with a plurality of signals CU, CV and CW induced when the motor is driven. The disk drive apparatus further has a drive voltage controlling unit for controlling, in accordance with the edge detection signal XEG, the maximum value of a drive voltage VS for driving said motor. This arrangement implements optimal motor control, while reducing circuit scale and cost and, at the same time, enhancing adaptability of the disk drive apparatus.

Disk drive apparatus

Disk drive apparatus for optimum motor control

The present invention provides a disk driving apparatus which includes an interpolating edge circuit for generating an interpolating signal in accordance with a cycle of an edge detection signal, and a phase switching unit for performing phase switching by both the timing signal and the interpolating signal when a period for which the edge detection signal is normally generated reaches a predetermined value.

Disk driving apparatus

A high speed dubbing is to be realized with two recording and/or reproducing units for compressed data. To this end, a magneto-optical disc,is read by an optical head,and compressed data produced via a decoder,are delivered to a memory,via a switch,. The data are then delivered to a magnetic head driving circuit,via an encoder,for direct writing on a magneto-optical disc,. In this manner, compressed data are directly dubbed without expansion to realize high speed dubbing.

Recording/reproducing apparatus for compressed data

A motor rotation control circuit of a disc recording and/or reproducing apparatus has first and second rotation control units and a switching circuit. Information extracted from data read out from a disc is supplied to the first rotation control unit. The first rotation control unit forms a first control signal to rotate a disc rotating motor at a constant linear velocity. A signal indicative of the detection of the rotation of the motor to rotate, the disc is supplied to the second rotation control unit. The second rotation control unit forms a second control signal to rotate the motor at a constant angular velocity. The second rotation control unit fetches rotational speed information of the disc when switching from the first rotation control unit to the second rotation control unit and forms the second control signal to control the motor on the basis of the fetched rotational speed information of the disc when switched from the first rotation control unit to the second rotation control unit. The switching circuit switches the first and second control signals on the basis of a switching signal which is supplied from the controller and outputs the switched control signal. The switching circuit generates the first control signal from the first rotation control unit while the data is read out from the disc and generates the second control signal from the second rotation control unit while the reading operation of the data from the disc is stopped.

Disc recording and/or reproducing apparatus and its motor drive control

A phase locked loop circuit for extracting a clock component from an input signal and generating a phase locked clock signal. Operates to detect a partial loss of the input signal and keep the input signal of a low-pass filter that is one component of the circuit zero. The clock signal is controlled to be far from an originally assumed signal while a partial loss of the input signal is detected. Hence, the pull-in operation of the PLL is expedited after the normal clock signal can be extracted.

Phase locked loop circuit and reproducing apparatus provided with thereof

A high speed dubbing is to be realized with two recording and/or reproducing units for compressed data. To this end, a magneto-optical disc 32 is read by an optical head 33 and compressed data produced via a decoder 41 are delivered to a memory 14 via a switch 37. The data are then delivered to a magnetic head driving circuit 16 via an encoder 15 for direct writing on a magneto-optical disc 2. In this manner, compressed data are directly dubbed without expansion to realize high speed dubbing.

Recording and/or reproducing method and apparatus with dubbing mode

A defect detecting apparatus and a reproducing apparatus therewith are disclosed, the defect detecting apparatus includes a detector for detecting a first type of defect such as a black dot that takes place in a fabrication stage and a second type of defect such as fingerprints that adheres on an optical disc and a controller for controlling various servo signals corresponding to the detected result.

Defect detecting circuit and reproducing apparatus having the defect

A recording device for a disc-like recording medium having some recording tracks formed by grooves wobbled in response to their absolute positional information and the track including a linking area for controlling laser power, the recording device comprising an information reader for reading information from the disc-like recording medium, a frequency information extractor for extracting groove frequency information from information extracted by the information reader, a frequency measurer for measuring the frequency of the frequency information extracted by the frequency information extractor, a recorder for performing a recording operation in respect to the disc-like recording medium, a discriminator for discriminating whether a rotating speed of the disc-like recording medium has reached a suitable rotation velocity or not, and a controller for controlling a laser power at the linking area in advance for a recording operation if the rotating speed has reached a suitable rotation velocity in accordance with a result of the discriminator.

Recording or reproducing apparatus having a spindle servo control linked

A disc recording and reproducing apparatus for use with a disc cartridge which includes an exterior indicator for indicating a reflectance of an optical disc housed in a cartridge body thereof, the disc recording and reproducing apparatus including a detector for detecting the exterior indicator and a setting control circuit for initially setting an output level of a laser light irradiated on the optical disc based on a detection output from the detector before beginning recording or reproducing operations.

Disc recording and/or reproducing apparatus

A servo apparatus for which the servo operation remains stable even if the power supply voltages changes, and the control processing load and amount of control data necessary is reduced by setting up gain variation equipment so as to proceed phase compensators, or setting up gain variation equipment so as to proceed selectors, so that the gain set-up at the time of non-loop operations such as focus searches and track jumps etc. can be varied by the gain variation equipment and the extent of variation of the gain variation equipment can be controlled simultaneously for a number of servo systems.

Disc apparatus having servo circuits which compensate for fluctuations

A spindle rotational information is obtained and a positive spindle servo control or a recording operation control is carried out in the case that CLV servo is performed in reference to a groove information. A recording or reproducing device corresponding to a disc having some recording trucks formed therein by grooves wobbled in response to their absolute positional information is comprised of the information reading means 3, the frequency information extracting means 7, 10 for extracting groove frequency information, the frequency measuring means 21, the rotational servo means 9 and the control means 11. The control means 11 controls an operation of the rotational servo means in response to the result of measurement performed by the frequency measuring means 21. In the recording device, the control means 11 controls a recording operation timing with the recording means by using the result of measurement performed by the frequency measuring means 21.

Clock reproducing device utilizing a frequency of wobble groove

A spindle servo circuit controls the rotation of a disc-driving spindle motor based on absolute address information taken from a disc. Reproduction digital data is written to and read from a RAM. An address control circuit generates a write address of the RAM by counting clocks synchronized with the reproduction digital data by a first counter, and generates a read address of the RAM by counting reference clocks by a second counter. A jitter correction circuit produces jitter-removed reproduction digital data from the RAM. The address control circuit is reset so that the address margin of the RAM is maximized when the spindle servo circuit is locked.

Disc recording/reproduction apparatus and method for resetting an

A recording or reproducing device for a disc shape recording medium of the type having wobbled grooves includes a circuit for reproducing the recording medium, a circuit for extracting groove information, comparing the frequency of the groove information with a predetermined value, and determining from the comparison if the spindle servo is in a runaway state, and a control circuit which disables a PLL circuit in a spindle servo control if a runaway state is detected to thereby stop the runaway state.

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Tokyo, Japan

Ryo Ando