Matsushita Electric Industrial Co., Ltd.

Yukihiro Yamasaki

Yuji Hisakado

Toshiya Akagi

Mamoru Shoji

Shinichi Konishi

Chikashi Inokuchi

Takashi Ishida

Toshihiko Takahashi

Takeshi Nakajima

Harumitsu Miyashita

Ariaki Ito

Atsushi Nakamura

Shigeru Furumiya

Tamotsu Matsuo

Jun'ichi Minamino

Toshio Suetsugu

Hideo Okamura

Yasuhiro Honda

Jun-ichi Minamino

An optical disk drive and recording power determination method determine the optimum power with consideration for the recording state of a base layer track when determining the optimum power by test recording before recording user data. After recording at a second recording power that is higher than a first recording power by a specific amount, recording is performed at a third recording power that is lower than the first recording power by a specific amount, and the first recording power is set to the recording power for data recording when a specified playback signal quality is achieved.

Optical disk device and recording power determining method

An optical disc drive usable with discs to which data is continuously recorded and discs having a sector format can quickly resume playback signal output after passing imperfection causing potential reading errors, and plays disc with few read errors. A detection signal generator detects DC level fluctuation in the playback signal read from the disc and generates a detection signal tracking the DC level fluctuation. A selector selects a detection signal or a null signal without valid polarity based on the detection signal generated by the detection signal generator and input to the selector. A clamping unit performs a clamping process to suppress DC level fluctuation in the playback signal based on the detection signal when the selection unit selects the detection signal, and does not perform the clamping process when the selection unit selects the null signal. A signal processor performs specific signal processes based on clamping unit output.

Optical disc device

The optical disk recording apparatus of this invention includes: a first detection section for detecting a ID address cycle based on a timing of detection of an ID section of an optical disk; a second detection section for detecting a wobble cycle based on a wobble clock; and a state determination section for determining a state of the wobble clock based on the ID address cycle and the wobble cycle.

Optical disk recording apparatus and method for recording data on optical disk

The invention provides an optical disc device and a method of determining an optimal laser power for data recording by trial recording before recording actual user data even when there are fingerprints in the test track area for the trial recording. The BER (Byte Error Rate) is detected in each recorded sector. If the BER is less than a particular threshold value, the sector is taken as OK (good). Otherwise the sector is taken as NG (no good). While the peak power level is gradually changed or decreased from the power level at which half or more of the plural reproduced sectors are OK, a boundary peak power at which half or more of the sectors become NG is found. Based on the found boundary power, an amount of the optimal peak power is determined.

Method and apparatus for determining optical recording power used for recording onto an optical disk

An optical disk is operated in a ZCLV system for generating a stable and precise clock and the operation proceeds with a speed change of a high-speed motor when data is stored with the motor accelerated or decelerated at a high speed to improve accessibility for data storage. The optical disk includes: a disk rotator for rotating the optical disk at an optional number of rotations; a rotation controller for controlling rotation of the optical disk; a wobble extractor for extracting wobbling on the track of the optical disk; a clock extractor for extracting a clock element from the wobbling; a speed detector for detecting a linear speed of the optical disk; and a response switch for switching a response of the clock extractor, in which the response of the clock extractor is switched depending on the linear speed of the optical disk.

Optical disk device

A regenerated signal process circuit of an optical disk device is developed to solve the problem that a jitter margin is lowered without an optimum regeneration condition because, when data is regenerated independent of a transfer rate, a data frequency fluctuates against a set value of an AGC, a waveform equalization circuit, a binarization circuit, or the like. In a signal process circuit, a set value of the AGC (,), the waveform equalization circuit (,), the binarization circuit (,), or the like is controlled by referring to the amount of oscillation control current of the VCO (,) of a frequency synthesizer. The characteristics of the VCO of the data PLL (,) is set equal to the characteristics of the VCO (,) of the frequency synthesizer, and each set value is controlled by referring to the oscillation control current of each VCO. Then, the reference current is switched depending on the synchronization state of the data PLL (,). In addition, the gain of the charge pump (,) is adjusted based on the division ratio of the N divider (,) such that the frequency synthesizer has loop characteristics of constant and stable oscillation.

An optical disk device of the present invention performs at least one of recording and reproduction of an optical disk in which a wobble signal is included along a data-recording track, by rotating the optical disk and by scanning the track on the optical disk using an optical head. The device includes: an extraction section for extracting the wobble signal of the optical disk from an output of the optical head; a synchronization clock generation section for generating a synchronization clock signal based on the wobble signal extracted by the extraction section; and a recording/reproduction section for performing at least one of recording and reproduction of data to/from the optical disk by the synchronization clock signal generated by the synchronization clock generation section.

Optical disk device with abnormal jump detection

The data recording/reproducing device according to the present invention, in response to the detected signal output from the data error detector, repeats a reading operation to form a data from a reproduced signal. The gate signal generator includes an envelope detector and a comparator. The envelope detector has a time constant which is changed in accordance with the detected signal output from the data error detector, and forms a threshold signal that generally follows a level variation of the reproduced signal in accordance with the time constant. The comparator compares the reproduced signal and the threshold signal output from the envelope detector so as to form the gate signal.

Data recording/reproducing device and recording medium

In an optical data recording and reproducing apparatus comprising an information signal generator, a sample/hold switching signal generator, a write/read switching signal generator, a laser beam source, a reference voltage generator, a comparator and a photo detector, a dummy signal is added to the information signal modulating the laser beam or generation of the laser beam is forcedly stopped after a data write servo mode so as to prevent generation of the laser beam of an excessively high level at the time of change-over from the data write servo mode to a data write hold mode or from the data write hold mode to a data read mode, or the level of the write/read switching signal is changed before the level of the sample/hold switching signal is changed at the time of change-over from the data write hold mode to the data read mode, or the duration of emission of the laser beam is extended slightly before the level of the sample/hold switching signal is changed.

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Hirakata, Japan

Yukihiro Yamasaki