摘要:
An optical disk apparatus includes a semiconductor laser for emitting a light beam, and an automatic power control or APC circuit for driving the laser. A compound prism structure is optically coupled to the laser in an optical head section, and defines a first optical path for causing a front laser light to be projected onto a rotating optical disk and guiding a reflected light therefrom toward a first photodetector, and a second optical path for guiding a part of the reflected light toward a second photodetector. An output signal of the first photodetector is used to generate a reproduced information signal. An output signal of the second photodetector is fed back to the APC circuit as a front light monitor signal. A part of a laser control signal internally generated in the APC circuit is supplied through a wiring line to a noise reduction circuit as a laser noise monitor signal. The noise reduction circuit subtracts this noise monitor signal from the reproduced information signal to provide a noise-suppressed information signal.
摘要:
According to this invention, general addresses are given to a multi-layer information storage medium to facilitate handing of information. That is, it is possible to set generalized addresses for multiple information layers, and information indicating a condition for setting the general addresses, e.g., the contents of a disk ID zone in a rewritable zone of a lead-in area, is recorded on an information reproducing layer.
摘要:
Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.
摘要:
Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.
摘要:
Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.
摘要:
Signal processing systems can be switched according to the optical system selected from a plurality of optical systems and set to the operating state. A system controlling portion 100 finally sets an appropriate optical system according to the kind of an optical disk 11, and sets an appropriate signal processing system corresponding to the set optical system for setting an appropriate mode depending upon CD (compact disk) or DVD (high density recording disk).
摘要:
An optical head is fed to the innermost area of an optical disk, and then fed to the outside while a detector circuit measures the frequency of a read signal supplied from the optical head. When the frequency of the read signal changes to high frequency, a tracking servo is performed, and the read signal is analyzed to acquire positional information during the tracking servo operation. The tracking servo operation is disabled, and the optical head is fed to a target position based on the positional information.
摘要:
An excellent waveform signal with less jitter is obtained as an output signal from a reproducing optical pickup, irrespective of a relative reading speed. Thus there is no need for an equalizing circuit on a reproducing apparatus side. An input bit sequence or a recording NRZI signal is combined with spatial frequency characteristics G(fs) by a G(fs) converter. An output signal from the G(fs) converter is combined with equalizing frequency characteristics EQ(fs) necessary on a reproducing side by an EQ(fs) converter. An output from the EQ(fs) converter is saturation-amplified by a saturation amplifier, thereby producing an ideally pre-jittered recording signal that has equivalent enhanced high-frequency component. The recording signal is recorded on an optical disk.
摘要:
An optical disk device includes first pickup portion PU1 which outputs first detection signal by irradiating first laser beam having first wavelength to surface of optical disk and receiving its reflected light, second pickup portion PU2 having independent structure, which irradiates second laser beam having second wavelength and receives its reflected light so as to output second detection signal, and control portion in which with the first laser beam and the second laser beam so as to receive the first detection signal and the second detection signal, when system data of first class disk system area is detected from the first detection signal, the optical disk is determined to be the first class disk and when system data of second class disk system area is detected from the second detection signal, that optical disk is determined to be the second class.
摘要:
The length of a format modulation area in an address segment is limited to be 25% of the address-segment length or less, and the position of the format modulation area is selectable two possible positions. Subsequently, where a CLV optical-disk medium is used, wobble modulation areas in adjacent recording tracks do not overlap each other in the radius direction.