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US 6,646,574 B2Granted
Method for recording information, method for reproducing information, and information recording apparatus
AssigneeHitachi, Ltd.
InventorsTakeshi Maeda, Yukari Katayama, Hiroyuki Minemura
Life of this patent
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Abstract
A method and apparatus for recording and reproducing information to and from an optical disk. If the size of a shortest mark is made small, a signal amplitude lowers and errors are likely to occur. In order to overcome this problem, when data of asymmetric codes is written, the length of a write mark is compensated so that the shortest mark and gap have the same length.
Claims1
An information recording apparatus, comprising:
- a laser driven circuit for driving a laser to be applied to a recording medium;
- a modulation circuit for modulating user data into channel data,
- wherein a first channel data corresponding to a write waveform for forming a shortest mark and second channel data corresponding to a write waveform for forming a shortest gap between mark are asymmetric;
- a mark length compensation circuit for shortening a pulse length corresponding to a shortest mark length of data of an NRZ format supplied from said modulation circuit by a half of a detection window width;
- and
- a write waveform generating circuit for converting data supplied from said mark length compensation circuit into a voltage waveform.
3 more elements
Dependencies are inferred from the claim text.