Pulse shape modulation and information recording and reproducing technique using pulsed laser beam
AssigneeRicoh Company, Ltd.
InventorIppei Ogawa
Life of this patent
Estimating the term…
Abstract
In the disclosed pulse shape modulation method, an amplitude modulation gain for a reproduced signal from an information recording medium that makes the jitter of the reproduced signal become the minimum is specified. Then, it is determined whether the amplitude modulation gain corresponding to the minimum jitter resides within a prescribed range. If the amplitude modulation gain corresponding to the minimum jitter is outside the prescribed range, the pulse shape of the pulsed laser beam is modulated.
Claims18
A pulse shape modulation method for modulating a pulse shape of a pulsed laser beam used in recording operations for an information recording medium, based on the jitter of a reproduced signal from the information recording medium, the method comprising:
- specifying an amplitude modulation gain for the reproduced signal that makes the jitter the minimum;
- determining whether the amplitude modulation gain corresponding to the minimum jitter resides within a prescribed range;
- and
- modulating the pulse shape of the pulsed laser beam when the amplitude modulation gain corresponding to the minimum jitter is outside the prescribed range
An information recording method for recording information in an information recording medium using a pulsed laser beam, comprising:
- specifying an amplitude modulation gain for a reproduced signal of test data from the information recording medium that makes the jitter the minimum;
- determining whether the amplitude modulation gain corresponding to the minimum jitter resides within a prescribed range;
- modulating the pulse shape of the pulsed laser beam when the amplitude modulation gain corresponding to the minimum jitter is outside the prescribed range;
- and
- recording the information in the information recording medium using the pulse modulated laser beam.
An information recording and reproducing apparatus for recording information in an information recording medium using a pulsed laser beam, comprising:
- a reproduced signal processing circuit that acquires an amplitude modulation gain for a reproduced signal from the information recording medium that makes the jitter of the reproduced signal become the minimum;
- a laser control circuit that modulates a pulse shape of the pulsed laser beam when the amplitude modulation gain corresponding to the minimum jitter is not within a prescribed range, and
- an optical pickup that records the information in the information recording medium using the pulse-modulated laser beam.
An information recording and reproducing apparatus for recording information in an information recording medium using a pulsed laser beam, comprising:
- gain acquiring means for acquiring an amplitude modulation gain for a reproduced signal from the information recording medium that makes the jitter of the reproduced signal become the minimum;
- pulse shape modulation means for modulating a pulse shape of the pulsed laser beam when the amplitude modulation gain corresponding to the minimum jitter is not within a prescribed range, and
- recording means for recording the information in the information recording medium using the pulse-modulated laser beam.
Dependencies are inferred from the claim text.