摘要:
This optical disc drive has an optical pickup head that emits a light beam to an optical storage medium, detects the light beam reflected from the optical storage medium, and outputs a signal based on the received reflected light; a jitter measuring unit for measuring jitter in signals output from the optical pickup head; and an evaluation unit for determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.
摘要:
This optical disc drive has an optical pickup head that emits a light beam to an optical storage medium, detects the light beam reflected from the optical storage medium, and outputs a signal based on the received reflected light; a jitter measuring unit for measuring jitter in signals output from the optical pickup head; and an evaluation unit for determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.
摘要:
An optical information apparatus comprises an optical pick-up head including: a light source emitting a light beam; a diffraction unit receiving a beam emitted from the light source to generate a plurality of diffracted beams composed of a 0th order diffracted light beam and a 1st or higher order diffracted light beam; a condensing unit receiving the plurality of diffracted beams from the diffraction unit and condensing the beams onto an optical recording medium; a beam splitter receiving the plurality of beams reflected from the optical recording medium and splitting the beams; and a photodetector receiving the beams split by the beam splitter and outputting signals in accordance with amounts of the received light beams, wherein the 0th order diffraction light beam generated in the diffraction unit is set to be a main beam, and two 1st or higher order diffracted light beams generated in the diffraction unit are set to be a first sub-beam and a second sub-beam; the photodetector has a plurality of light-receiving portions; and the main beam, the first sub-beam, and the second sub-beam are received by the plurality of light-receiving portions, respectively. The apparatus further comprises a tracking error signal generator generating a tracking error signal for irradiating a desired track with a beam. The optical recording medium has an information recording surface for recording information, the optical recording medium has a reflective surface for reflecting the beam to a region other than the information recording surface when the beam is condensed onto the information recording surface, and guide grooves are formed on the optical recording medium. The optical recording medium has tracks for recording information, arranged substantially at a constant pitch, on the information recording surface, and the tracks are provided on the guide grooves or between the guide grooves. When the main beam is placed on the track, the first sub-beam and the second sub-beam are respectively placed between the tracks. The tracking error signal generator performs a differential arithmetic operation with respect to signals output from the light-receiving portion receiving the main beam to generate a first push-pull signal, performs a differential arithmetic operation with respect to signals output from the light-receiving portions receiving the first sub-beam and the second sub-beam to generate a second push-pull signal, and performs a differential arithmetic operation with respect to the first push-pull signal and the second push-pull signal to generate the tracking error signal. Regions in a vicinity of centers of the main beam, the first sub-beam, and the second sub-beam are split by providing the beam splitter in an optical path from the optical information recording medium to the photodetector, the first push-pull signal is generated without using the region in the vicinity of the center of the main beam, and the second push-pull signal is generated without using the regions in the vicinity of the centers of the first sub-beam and the second sub-beam.
摘要:
This optical disc drive has an optical pickup head that emits a light beam to an optical storage medium, detects the light beam reflected from the optical storage medium, and outputs a signal based on the received reflected light; a jitter measuring unit for measuring jitter in signals output from the optical pickup head; and an evaluation unit for determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.
摘要:
This optical disc drive has an optical pickup head that emits a light beam to an optical storage medium, detects the light beam reflected from the optical storage medium, and outputs a signal based on the received reflected light; a jitter measuring unit for measuring jitter in signals output from the optical pickup head; and an evaluation unit for determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.
摘要:
An optical information apparatus, comprises an optical pick-up head including: a light source emitting a light beam; a diffraction unit receiving a beam emitted from the light source to generate a plurality of diffracted beams composed of a 0th order diffracted light beam and a 1st or higher order diffracted light beam; a condensing unit receiving the plurality of diffracted beams from the diffraction unit and condensing the beams onto an optical recording medium; a beam splitter receiving the plurality of beams reflected from the optical recording medium and splitting the beams; and a photodetector receiving the beams split by the beam splitter and outputting signals in accordance with amounts of the received light beams, wherein the 0th order diffraction light beam generated in the diffraction unit is set to be a main beam, and two 1st or higher order diffracted light beams generated in the diffraction unit are set to be a first sub-beam and a second sub-beam; the photodetector has a plurality of light-receiving portions; and the main beam, the first sub-beam, and the second sub-beam are received by the plurality of light-receiving portions, respectively. The apparatus further comprises a tracking error signal generator generating a tracking error signal for irradiating a desired track with a beam. Guide grooves are formed on the optical recording medium, the optical recording medium has tracks for recording information, arranged substantially at a constant pitch, and the tracks are provided on the guide grooves or between the guide grooves. An average of the pitch is tp. When the main beam is placed on the track, the first sub-beam and the second sub-beam are respectively placed between the tracks. The tracking error signal generator performs a differential arithmetic operation with respect to signals output from the light-receiving portion receiving the main beam to generate a first push-pull signal, and performs a differential arithmetic operation with respect to signals output from the light-receiving portions receiving the first sub-beam and the second sub-beam to generate a second push-pull signal. An amplitude of the first push-pull signal obtained at the pitch tp when the light beam is scanned in a direction orthogonal to the tracks of the optical recording medium is changed at a pitch different from the pitch tp, due to a fact that a track in which information is not recorded is adjacent to a track in which information is recorded or that a pitch of the track formed on the optical recording medium is partially different from the pitch tp. The first push-pull signal is generated using a polarity or amplification coefficient k different from that of an arithmetic operation for obtaining an ordinary push-pull signal with respect to a region in a vicinity of a center of the main beam. The second push-pull signal is generated using a polarity or amplification coefficient k different from that of an arithmetic operation for obtaining an ordinary push-pull signal with respect to a region in a vicinity of respective centers of the first sub-beam and the second sub-beam. A differential arithmetic operation is performed with respect to the first push-pull signal and the second push-pull signal to generate the tracking error signal.
摘要:
An optical disc apparatus includes a control section. The control section performs a first search while the tracking control is in the off state. The first search is for searching for a plurality of sets of the focus positions of the light beam and the spherical aberration amounts such that an amplitude of the tracking error signal is greater than a predetermined value. The control section performs a second search while the tracking control is in the on state. The second search is for determining a set of the focus position of the light beam and the spherical aberration amount such that the reproduced signal quality index is substantially optimal, among the plurality of sets of the focus positions of the light beam and the spherical aberration amounts obtained in the first search.
摘要:
This optical disc drive has an optical pickup head that emits a light beam to an optical storage medium, detects the light beam reflected from the optical storage medium, and outputs a signal based on the received reflected light; a jitter measuring unit for measuring jitter in signals output from the optical pickup head; and an evaluation unit for determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.
摘要:
This optical disc drive has an optical pickup head that emits a light beam to an optical storage medium, detects the light beam reflected from the optical storage medium, and outputs a signal based on the received reflected light; a jitter measuring unit for measuring jitter in signals output from the optical pickup head; and an evaluation unit for determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.