Sony Corporation

Yoshiyasu Masuda

Takashi Sasaki

Mitsuyuki Bamba

Munetoshi Moriichi

Tsunemitsu Takase

When performing writing and/or reading of information to/from an optical disk provided with a wobble including time axis information, an occurrence of a reading error of the time axis information from the wobble is suppressed so that disabled reading of information from the optical disk and an occurrence of a writing error can be prevented. Evaluated parameters such as a CRC error rate of an ATIP signal, an FMDT jitter amount and a phase error between an ATIP synchronization signal and a frame synchronization signal of writing data are evaluated based on a range of set values. When the evaluated parameter is deviated from the range of set values, writing and reading speeds are changed, thereby increasing the reading accuracy of the wobble signal.

Optical writing device, optical reading device, recording-medium writing method, including wobble signal evaluation features

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.

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Tokyo, Japan

Yoshiyasu Masuda