Abstract: Address information is formed by M wobbles (integer M is the number of wobble waves) per bit as a basic unit, and is NRZ-recorded. Also, a sync signal used in sync detection of the address information is formed by N wobbles per bit as a basic unit (integer N is the number of wobble waves and M=2N). The sync signal with such configuration (6 wobbles per bit) is recorded on the head side of the address information (12 wobbles per bit). In this way, even when external noise is large, a modulated wobble signal can be demodulated more accurately.

Abstract: Address information is formed by M wobbles (integer M is the number of wobble waves) per bit as a basic unit, and is NRZ-recorded. Also, a sync signal used in sync detection of the address information is formed by N wobbles per bit as a basic unit (integer N is the number of wobble waves and M=2N). The sync signal with such configuration (6 wobbles per bit) is recorded on the head side of the address information (12 wobbles per bit). In this way, even when external noise is large, a modulated wobble signal can be demodulated more accurately.

Abstract: Address information is formed by M wobbles (integer M is the number of wobble waves) per bit as a basic unit, and is NRZ-recorded. Also, a sync signal used in sync detection of the address information is formed by N wobbles per bit as a basic unit (integer N is the number of wobble waves and M=2N). The sync signal with such configuration (6 wobbles per bit) is recorded on the head side of the address information (12 wobbles per bit). In this way, even when external noise is large, a modulated wobble signal can be demodulated more accurately.

Abstract: An optical disk recording apparatus is configured to record information on a multilayer optical disk having a general information recording area for recording general information and a management information recording area for recording management information which manages general information recorded on this general information recording area. In this optical disk recording apparatus, meaningless information is recorded on an unrecorded area in the management information recording area of the optical disk.

Abstract: An information storage medium according to an embodiment of this invention includes a wobble track whose wobble period is modulated by multi-frequency shift keying corresponding to playback control information, wherein the playback control information contains header data and address data, and the header data contains a VFO area formed from a predetermined frequency.

Abstract: Address information is formed by M wobbles (integer M is the number of wobble waves) per bit as a basic unit, and is NRZ-recorded. Also, a sync signal used in sync detection of the address information is formed by N wobbles per bit as a basic unit (integer N is the number of wobble waves and M=2N). The sync signal with such configuration (6 wobbles per bit) is recorded on the head side of the address information (12 wobbles per bit). In this way, even when external noise is large, a modulated wobble signal can be demodulated more accurately.

Abstract: An information storage medium according to an embodiment of this invention includes a wobbled groove having a wobble period modulated by multi-frequency shift keying corresponding to playback control information.

Abstract: An optical disk recording apparatus is configured to record information on a multilayer optical disk having a general information recording area for recording general information and a management information recording area for recording management information which manages general information recorded on this general information recording area. In this optical disk recording apparatus, meaningless information is recorded on an unrecorded area in the management information recording area of the optical disk.

Abstract: An optical disk apparatus of the invention includes an optical pickup which irradiates an optical disk with a laser beam, a light-reception unit including a first light-reception element and a second light-reception element, the light-reception unit receiving the laser beam reflected from the optical disk to provide a first photodetection signal and a second photodetection signal corresponding to the reflected laser beam, measuring units and which receive the first and second photodetection signals from the optical pickup to measure propagation delay time difference between the first and second photodetection signals, a delay unit which delays the first and second photodetection signals based on the signal propagation delay time difference such that delay times of the first and second photodetection signals are equalized to each other, and a signal processing circuit which processes the first and second photodetection signals delayed by the delay unit, and provides the processed signals.

Abstract: An optical disk recording apparatus is configured to record information on a multilayer optical disk having a general information recording area for recording general information and a management information recording area for recording management information which manages general information recorded on this general information recording area. In this optical disk recording apparatus, meaningless information is recorded on an unrecorded area in the management information recording area of the optical disk.

Abstract: An information storage medium has a system lead-in area and a data lead-in area, and an area identifying circuit identifies whether a light beam irradiation area of an optical pickup head is at the system lead-in area or at the data lead-in area based on a reproduction signal provided from the optical pickup head. The area identifying circuit identifies the respective areas by using the number of zero crossings obtained from a signal, for example, into which the reproduction signal is binarized. An information reproducing circuit reproduces information from the reproduction signal based on the identified result by the area identifying circuit.

Abstract: An optical disk in which tracks in which a header region at which positional information showing a recorded position is recorded and a user region at which user information is recorded are alternately arranged, and in which the user region is made to wobble in a direction perpendicular to the arranging direction are formed, and in which a first region in which at least one of a phase, a frequency, and an amplitude of a wobble is different from the other portions is formed at a portion a given length before the header region in playback order within the user region.

Abstract: This invention relates to a focus control apparatus having a controller which generates a control signal and performs focus operation when the peak timing of a focus sum signal based on reflected light and the zero-crossing timing of a focus error signal are detected to substantially coincide with each other in supplying a control signal to a lens actuator driver for supplying a driving signal to a lens actuator for driving a lens. The invention also relates to an optical disk apparatus using the focus control apparatus. By detecting coincidence of the two timings, two reflected waves are discriminated, and stable focus operation is achieved.

Abstract: An information storage medium according to an embodiment of this invention includes a wobble track whose wobble period is modulated by multi-frequency shift keying corresponding to playback control information, wherein the playback control information contains header data and address data, and the header data contains a VFO area formed from a predetermined frequency.

Abstract: An information storage medium according to an embodiment of this invention includes a wobbled groove having a wobble period modulated by multi-frequency shift keying corresponding to playback control information.

Abstract: An information storage medium includes a wobbled track containing a wobble modulated in correspondence with playback control information. The playback control information contains address data. Part of the address data contains at least one item of sync information. The frequency of the wobble changes at the boundary of the sync information.

Abstract: An information storage medium has a wobbled groove whose wobble period is modulated by multi-frequency shift keying corresponding to playback control information, and one wavelength of the lowest frequency contained in the multi-frequency shift keying is an integer multiple of a half wavelength of the remaining frequencies contained in the multi-frequency shift keying.

Abstract: An information storage medium which stores data with an error correction code includes wobble grooves, whose wobble period is modulated in correspondence with address information, in which a length smaller than the maximum error-correctable data length of the data with the error correction code, which is stored along the wobble grooves, is defined as a basic unit, and the address information in the basic unit is reflected in the modulation of the wobble period of the wobble grooves.

Abstract: An optical disk recording apparatus is configured to record information on a multilayer optical disk having a general information recording area for recording general information and a management information recording area for recording management information which manages general information recorded on this general information recording area. In this optical disk recording apparatus, meaningless information is recorded on an unrecorded area in the management information recording area of the optical disk.