Abstract: A phase error detection apparatus capable of performing offset correction of a tracking error signal accurately even when there is a defect or a non-recorded position on an optical disc. There are provided a phase difference detection circuit (107) which receives two sequences of digital signals, performs phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputs a phase comparison result PCR and a phase comparison completion signal PCC, and an offset control circuit (11) which outputs an offset correction amount for each phase comparison completion signal PCC from the phase difference detection circuit (107), and the offset correction amount ?? is added to the phase comparison result PCR to avoid offset correction in a position where phase comparison is not carried out.

Abstract: An optical disc device including a high frequency band processing circuit for removing low frequency components of signals outputted from plural photodetectors of a pickup, and generating various kinds of signals required for recording/playback of an optical disc by digital processing after performing AD conversion by a high-speed low-bit AD converter; and a low frequency band processing circuit for removing high frequency components of the signals outputted from the respective photodetectors of the pickup, and generating various kinds of signals required for recording/playback of an optical disc by digital processing after performing AD conversion by a low-speed high-bit time-division AD converter.

Abstract: A phase error detection apparatus capable of performing offset correction of a tracking error signal accurately even when there is a defect or a non-recorded position on an optical disc. There are provided a phase difference detection circuit (107) which receives two sequences of digital signals, performs phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputs a phase comparison result PCR and a phase comparison completion signal PCC, and an offset control circuit (11) which outputs an offset correction amount for each phase comparison completion signal PCC from the phase difference detection circuit (107), and the offset correction amount ?? is added to the phase comparison result PCR to avoid offset correction in a position where phase comparison is not carried out.

Abstract: The address signal position detection apparatus comprises a photodetector, a first and second adders which generate, from the output signals from the photodetector, two signal sequences whose phases change from each other according to a tracking error of a light spot, a phase difference detection circuit for detecting the phase difference from the two signal sequences, and a phase difference signal processing unit which generates an address signal position using the phase difference signal detected by the phase difference detection circuit, and detects an address signal position by providing threshold values with respect to the detected phase difference, thereby enabling a stable detection of the address signal position even when a DC symmetry in a difference signal of a reproduced signal is imperfect in an optical disk using the land/groove recoding method.

Abstract: A tracking error detection apparatus comprises a photodetector comprising plural photoreceptor elements; zerocross detection circuits for detecting zerocross points at which two sequences of digital signals intersect the center levels of the respective digital signals, which digital signals are generated according to the amounts of light received by the respective photoreceptor elements and are outputted from the photodetector; a phase difference detection circuit for performing phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputting a result of phase comparison; and a low-pass filter for performing band restriction to a signal outputted from the phase difference detection circuit. When a phase difference between the two sequences of digital signals, which is detected by the phase difference detection circuit, is larger than a maximum value of a theoretical tracking error signal, the output from the phase difference detection circuit is limited.

Abstract: A tracking error detection apparatus comprises a phase difference detection circuit for receiving two sequences of digital signals, and performing phase comparison using a distance between zerocross points of the two sequences of digital signals to output a result of phase comparison, and an LPF for generating a tracking error signal from the result of phase comparison. The phase difference detection circuit does not carry out phase composition in a position that is not appropriate as a target position to perform phase comparison, and outputs the result of phase comparison as a pulse signal corresponding to one sampling clock. Therefore, even when a disc is played at CAV or a flaw or the like exists on the disc, an accurate tracking error signal can be detected.

Abstract: An optical disc device according to the present invention is provided with, as shown in FIGS. 1 and 2, a high frequency band processing circuit for removing low frequency components of signals outputted from plural photodetectors of a pickup, and generating various kinds of signals required for recording/playback of an optical disc by digital processing after performing AD conversion by a high-speed low-bit AD converter; and a low frequency band processing circuit for removing high frequency components of the signals outputted from the respective photodetectors of the pickup, and generating various kinds of signals required for recording/playback of an optical disc by digital processing after performing AD conversion by a low-speed high-bit time-division AD converter. Thereby, various kinds of signals required for recording/playback of an optical disc can be generated using a single circuit, whereby the product cost, power consumption, and circuit scale can be reduced.

Abstract: A tracking error detection apparatus includes a phase error detection unit for detecting a phase error of an output signal according to the amount of reflected light that is obtained when a light beam is applied to an information recording medium and a low-band pass unit for performing band restriction to obtain a tracking error signal from the phase error signal. The tracking error detection apparatus also includes a clock generation unit for generating a clock and a clock control unit having a frequency divider for generating a frequency-divided clock of the clock that is generated by the clock generation unit, wherein the clock control unit uses the frequency-divided clock as an operation clock for the tracking error detection apparatus. Therefore, the operation rate of each unit when generating a tracking error signal can be reduced, whereby a reduction in power consumption is achieved.

Abstract: The address signal position detection apparatus comprises a photodetector, a first and second adders which generate, from the output signals from the photodetector, two signal sequences whose phases change from each other according to a tracking error of a light spot, a phase difference detection circuit for detecting the phase difference from the two signal sequences, and a phase difference signal processing unit which generates an address signal position using the phase difference signal detected by the phase difference detection circuit, and detects an address signal position by providing threshold values with respect to the detected phase difference, thereby enabling a stable detection of the address signal position even when a DC symmetry in a difference signal of a reproduced signal is imperfect in an optical disk using the land/groove recoding method.

Abstract: A tracking error detection apparatus comprises a photodetector comprising plural photoreceptor elements; zerocross detection circuits for detecting zerocross points at which two sequences of digital signals intersect the center levels of the respective digital signals, which digital signals are generated according to the amounts of light received by the respective photoreceptor elements and are outputted from the photodetector; a phase difference detection circuit for performing phase comparison using a distance between zerocross points of the two sequences of digital signals, and outputting a result of phase comparison; and a low-pass filter for performing band restriction to a signal outputted from the phase difference detection circuit, thereby to obtain a tracking error detection apparatus.

Abstract: A tracking error detection apparatus comprises a phase difference detection circuit for receiving two sequences of digital signals, and performing phase comparison using a distance between zerocross points of the two sequences of digital signals to output a result of phase comparison, and an LPF for generating a tracking error signal from the result of phase comparison. The phase difference detection circuit does not carry out phase composition in a position that is not appropriate as a target position to perform phase comparison, and outputs the result of phase comparison as a pulse signal corresponding to one sampling clock. Therefore, even when a disc is played at CAV or a flaw or the like exists on the disc, an accurate tracking error signal can be detected.

Abstract: A tracking error detecting apparatus converts photoelectric current obtained by a photo detector into voltage signals at current/voltage conversion circuits, and adds the voltage signals to generate two signal series at adders. The two signal series are digitalized at analog to digital converters, are subjected to interpolation processing at interpolation filters and have their zero cross points detected by zero cross point detector circuits respectively. A phase difference between the zero cross points of the two signal series is detected by a phase difference detector circuit, and the phase difference is subjected to band restriction by a low pass filter, thereby to obtain a tracking error signal. The tracking error detecting apparatus is capable of coping with speed doubling of an optical recording/reproducing apparatus and density enhancing of an optical recording medium with a small size and at low cost.

Abstract: A tracking error detection apparatus includes a phase error detection unit for detecting a phase error of an output signal according to the amount of reflected light that is obtained when a light beam is applied to an information recording medium; a low-band pass unit for performing band restriction to obtain a tracking error signal from the phase error signal; a clock generation unit for generating a clock; and a clock control unit having a frequency divider for generating a frequency-divided clock of the clock that is generated by the clock generation unit; wherein the clock control unit uses the frequency-divided clock as an operation clock for the tracking error detection apparatus. Therefore, the operation rate of each unit when generating a tracking error signal can be reduced, whereby a reduction in power consumption is achieved.