Hitachi-lg Data Storage, Inc.

Hitachi, Ltd.

Tomoya Hoshi

Atsushi Yamada

Toru Kawashima

Mitsuhiro Nishidate

Tsuyoshi Toda

Koichiro Nishimura

Toshiro Kinugasa

Akihito Nishizawa

Hiroyuki Komatsu

Tooru Kawashima

Mitsuru Harai

It is to provide an optical disc recording apparatus and a recording power control method that are adapted to high-speed recording and can set an optimal erasing power with high accuracy. A test writing signal detector reproduces a test writing signal of a predetermined mark length or space length with varied power, and detects the number of error mark signals and an amplitude value of an envelope. A controller obtains a first threshold Peof the erasing power based on the number of error mark signals in a region where laser power is low, and obtains a second threshold Peof the erasing power based on the amplitude value in a region where the laser power is high. Then, the controller sets an optimal value of the erasing power from an average value of the first and second thresholds.

Optical disc recording apparatus and recording power control method

An optical disc apparatus capable of improving an overwrite performance for performing an overwrite operation on a re-writable type optical disc. The apparatus includes a calculating section which calculates out a recording power at the time of previously performing recording in a recording area of the optical disc, and a recording power determining section which determines a write power of the recording power calculated out by the calculating section as a write power of the currently recorded recording power, and at the same time, adjusts erase power, cooling power, and/or middle power of the recording power calculated out by the calculating section to finally determine the currently recorded recording power.

Optical disc apparatus and method for controlling overwrite power

In a method for adjusting a focus position for an optical disc, onto/from which in formation is recorded or reproduced, while adjusting the focus position of an optical reproducing means, upon a recording surface of an optical information recording medium having an area where information of the optical information recording medium is recorded in advance, comprising the following steps of: memorizing plural numbers of information relating to focus positions determined appropriately, which can be obtained from the area where the information of the optical information recording medium is recorded in advance; and adjusting the focus position for the optical disc loaded into an apparatus, from at lease one (1) signal relating to the focus position, which can be obtained from the optical disc, with utilizing a relationship between the plural numbers of information relating to the focus positions determined appropriately, memorized in advance, when reproduction of the information is impossible when the optical disc is loaded into the apparatus, thereby providing the focus position adjusting method and an optical disc apparatus applying the same therein, for enabling an appropriate focus adjustment even in case when DMA area cannot read out due to damages or defects therein.

Method for adjusting a focus position on an optical disc and an optical disc apparatus applying the same therein

In an optical disk apparatus, for reproducing information recorded on a recording surface of an optical disk, by setting such a focus condition that a tracking servo-error level comes to be maximum with a reflection light from the recording surface, while irradiating a light beam of a semiconductor laser, within a signal processor portionfor amplifying a RF signal reproduced from the optical disk is provided an equalizerfor lifting up high-frequency region of the RF signal, wherein an optimal control is made on an amount of lifting (i.e., EQ Boost Value) by the equalizer, depending upon a difference (&#x394;AF) between a focus offset amount at which the RF signal reproduced comes to be maximum and a focus offset amount at which jitter of the RF signal reproduced come to be minimum.

Optical disk apparatus with controller for changing an amount of lifting and a control method thereof

A digital recording/reproducing video camera apparatus which externally receives analog video and audio signals as a standard video signal for data compression and recording. Selection switches for switching between a camera pick-up mode and a line input mode are switched to their terminals a in the camera pick-up mode and switched to their terminals b in the line input mode. An output signal of a CCD is sent via an amplifier, the switch and an A/D converter to a digital signal processing circuit to generate color and luminance signals. The generated color and luminance signals are fed to a data compression/expansion circuit to remove redundant parts therefrom and then sent to a HDD for recording. In a line input record mode, a line input signal is supplied through the switch and A/D converter to the digital signal processing circuit to generate the color and luminance signals. The generated color and luminance signals are fed to the data compression/expansion circuit to remove redundant parts therefrom and sent to the HDD for recording. The video camera apparatus may include a video signal processing circuit for detecting a time base error in 1 sampling period or less of the synchronization signal caused by performing Y/C separating/demodulating operations on a digital signal and moves a center of a video part in response to its detection result.

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Fujisawa, Japan

Tomoya Hoshi