Sony Corporation

Mitsuyuki Bamba

Takashi Sasaki

Munetoshi Moriichi

Yoshiyasu Masuda

Atsushi Mori

Toshimasa Miyoshi

Tatsushi Sano

In a writing device for writing data at 1-time or higher recording rates, a first delay circuit capable of variably controlling a delay time in units of a relatively long time and a second delay circuit capable of variably controlling a delay time in units of a relatively short time are employed in a combined manner. A laser drive pulse can be controlled in the direction of the time base with high accuracy corresponding to any recording rates ranging from 1-time to higher, e.g., 8- or 12-time, speeds without using very large number stages of delay gates.

Writing device

A recording apparatus generates a first pulse (EQEFM signal) in accordance with recording data such as an EFM signal. A second pulse (first overdrive pulse) to be combined with substantially the leading edge of the first pulse is generated. A third pulse (end overdrive pulse) to be combined with substantially the trailing edge of the first pulse is generated. The first, second, and third pulses are combined to synthesize a driving pulse, and the driving pulse is supplied to a laser unit. At least one of the first, second, and third pulses is controlled so that one of the level and the pulse duration thereof is varied in accordance with the length of formed pits and lands.

Recording apparatus and recording method

A push pull signal is detected from a disk-shaped storage medium on which wobbling grooves are formed as recording tracks and address information is recorded by forming pre-pits on lands between adjacent grooves. The detected push-pull signal is compared with a reference voltage thereby generating a land pre-pit detection signal. Of pulses included in the land pre-pit detection signal, those pulses having a small pulse width are regarded as noise pulses and removed thereby obtaining a corrected land pre-pit detection signal. The number of pulses included in the land pre-pit detection signal is counted, and the reference voltage is controlled in accordance with the counted number of pulses.

Disk drive and detection method using pre-pit detection and push-pull signal generation

A method for recording on a write-once type optical disc. A laser light beam excited to light emission by a recording pulse having a pulse width corresponding to the length of a pit formed, with the recording power of substantially the leading end of the pulse being stepped over plural stages, is illuminated on a write-once type optical disc for recording. This enables recording with an optimal pit shape at a speed faster than a quadrupled speed, such as at an octupled speed or a duo-deca-tupled speed.

Optical disc recording method and apparatus

A plurality of periodical signals are generated as the moving body moves. The periodical signals are given respective fundamental values. The fundamental value of one of the periodical signals that has a maximum value is detected sequentially. An extension value is generated in such a manner as to be incremented or decremented when the detected fundamental value changes from one unit repetition range to another. Position detection information of the moving body is constructed as a combination of the detected fundamental value and the extension value. The position detection information is stored.

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Saitama, Japan

Mitsuyuki Bamba