Patent application number | Description | Published |
20080263430 | Data readout device and data readout method - A data readout device generates decoded data based on a decided data bit decided by performing a hard-decision on likelihood data, wherein the likelihood data is generated in accordance with an iterative decoding method corresponding to a turbo-coding process. The iterative decoding process is performed on a sampled value obtained by sampling a signal read out from a magneto-optical disk at a predetermined sampling period. The data readout device is made up of a reliability determination part and an error correcting decoder. The reliability determination part detects whether each obtained data bit was obtained from likelihood data within a predetermined range defined with respect to a histogram of log likelihood ratios. When it is detected that a data bit was obtained by a hard-decision on likelihood data within the predetermined range, the data bit is regarded as being obtained by a hard-decision whose reliability is not sufficient. In this way, the error correcting decoder can perform ECC-based decoding operations including loss-correction processes depending on respective reliability-determination results that distinguish reliabilities among respective data bits. Thus, the accuracy of decoded data is increased. The data transfer rate of transferring decoded data when reading out of the MO medium is also improved to the utmost. | 10-23-2008 |
20090031187 | DATA RECORDING/REPRODUCING APPARATUS AND DATA RECORDING/REPRODUCING METHOD - A data format, a data recording/reproducing method, and a data recording/reproducing apparatus are provided for effectively correcting data errors caused by dust and scratches on a recording medium even with the use of a conventional ECC. The data recording/reproducing apparatus includes a generation unit that generates predetermined data units by dividing an ECC sector including error correction codes generated by an error correction encoder into prescribed data units and encoding the prescribed units into iterative encoded data units using an iterative encoder so that the predetermined data units may consist of the iterative-encoded data units, a recording unit, a reproducing unit, an iterative decoder for conducting iterative decoding on the predetermined data units, and an error correction decoder. The apparatus further includes a distribution unit for distributing the predetermined data units generated by the generation unit. The distribution unit distributes the iterative encoded data units using at least two ECC sectors and records the distributed data units on a recording medium. | 01-29-2009 |
20100020432 | MAGNETIC DISK APPARATUS AND MAGNETIC DISK ACCESS CONTROL METHOD - A magnetic disk apparatus includes a magnetic disk provided with a data recording area and a servo-pattern area. The data recording area includes a non-magnetic area scattered with magnetic regions, and the servo-pattern area includes a plurality of magnetic regions each having a larger area than the magnetic regions in the data recording area. The magnetic disk apparatus also includes a reader for reading magnetization in the data recording area and the servo-pattern area, and a magnetizer for application of a magnetic field to the magnetic regions in the servo-pattern area for equalizing magnetization directions of the magnetic regions in the servo-pattern area before the reader starts to read the servo-pattern area. | 01-28-2010 |
20100020433 | MAGNETIC DISK APPARATUS AND MAGNETIC DISK ACCESS CONTROL METHOD - A magnetic disk apparatus includes a magnetic disk, a magnetic head, a reverse-pulse detector, and a re-magnetizer. The magnetic disk includes a data recording area and a servo-pattern area. The magnetic regions of the servo-pattern area have been pre-magnetized in the same direction or pre-magnetizing direction. The magnetic head is arranged to reciprocate radially of the magnetic disk. The reverse-pulse detector is provided for reading the servo-pattern area with the magnetic head before data recording or reproducing with respect to the data recording area is performed. The reverse-pulse detector detects, from servo reproduction signal pulses, reverse pulses corresponding to the reversal of magnetization direction relative to the pre-magnetizing direction. The re-magnetizer causes the magnetic head to perform the re-magnetizing of the magnetic regions in the servo-pattern area when the count of reverse pulses is not smaller than a threshold number. | 01-28-2010 |
20100020436 | MAGNETIC DISK APPARATUS AND MAGNETIC DISK ACCESS CONTROLLING METHOD - A magnetic disk apparatus includes a magnetic disk, a magnetic head, a servo reproduction signal generator and a magnetic head controller. The disk includes a data recording area and a servo-pattern area. The data recording area includes a non-magnetic area scattered with magnetic regions, and the servo-pattern area includes uniformly magnetized magnetic regions larger than the magnetic regions in the recording area. The magnetic head reciprocates radially of the disk, giving a magnetization direction to the magnetic regions in the data recording area and reading the magnetization direction of the magnetic regions in the data recording area and the servo-pattern area. The servo reproduction signal generator reads the servo-pattern area, using the magnetic head, via an absolute-value calculation circuit to generate a servo reproduction signal before the recording or reading with respect to the data recording area. The magnetic head controller performs recording or reproducing with respect to the data recording area by controlling the magnetic head based on the servo reproduction signal. | 01-28-2010 |
20100027155 | MAGNETIC DISK APPARATUS AND METHOD FOR CONTROLLING PROJECTING AMOUNT OF MAGNETIC HEAD - A magnetic disk apparatus includes a magnetic disk, and a magnetic head facing the magnetic disk. The magnetic disk apparatus also includes a thermal deforming member and a thermal deformation controller. The thermal deforming member is provided in the magnetic head for thermally deforming the magnetic head to change the projecting amount of the magnetic head toward the magnetic disk. The thermal deformation controller controls the driving power supplied to the thermal deforming member, so that the falling characteristic of the driving power in transition from an on-state to an off-state is gentler in inclination than the rising characteristic of the driving power in transition from an off-state to an on-state. | 02-04-2010 |
20100244580 | WIRELESS POWER SUPPLY APPARATUS - A wireless power supply includes: a power transmitting coil resonant at a first resonant frequency that generates a magnetic field resonance, a power receiving coil resonant at the first resonant frequency, a power receiving unit that outputs energy received by the power receiving resonant coil; a distance detector that detects a distance between the power transmitting resonant coil and the power receiving resonant coil; a power transmitting frequency controller that changes the first resonant frequency to a second resonant frequency on the basis of the distance detected by the distance detector; and a power receiving frequency controller that changes the first resonant frequency of the power receiving resonant coil from the first resonant frequency to a second resonant frequency on the basis of the distance detected by the distance detector. | 09-30-2010 |
20120212069 | WIRELESS POWER TRANSMITTING DEVICE AND WIRELESS POWER TRANSMISSION SYSTEM - A wireless power transmitting device includes a housing configured to have a feeding surface on which a power receiving device is to be placed; a power transmitting coil disposed inside the housing and configured to have a central axis that intersects with the feeding surface; and an alternating-current power supply configured to supply power to the power transmitting coil, wherein the feeding surface has raised and recessed portions in an area corresponding to a region inside an outer region of the power transmitting coil. | 08-23-2012 |
20130015720 | RESONANT FREQUENCY CONTROL METHOD, ELECTRIC POWER TRANSMITTING DEVICE, ELECTRIC POWER RECEIVING DEVICE IN MAGNETIC RESONANT TYPE POWER TRANSMISSION SYSTEM - In a resonant frequency control method in a magnetic field resonant coupling type power transmission system transmitting an electric power from a power transmitting coil to a power receiving coil using magnetic field resonance, a high-speed, accurate and real-time adjustment of the resonant frequency of a coil is realized. The phase of a voltage supplied to a power transmitting coil and the phase of a current that flows in the power transmitting coil or a power receiving coil is detected and the resonant frequency of the power transmitting coil or the power receiving coil is varied such that the phase difference between them becomes a target value. | 01-17-2013 |