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7423834 |
Convolution based multiple harmonic frequency repeatable runout compensation method and apparatus
Real-time correction of repeatable runout for multiple harmonic frequencies is provided by using convolution of a position error signal, or similar real-time signal, with an impulse response of a...
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7408735 |
Data tracking method and apparatus for disk-based data storage
A method and apparatus for dealing with undesired deviations of servo burst component magnitudes, as compared with nominal magnitudes, is provided. Inaccurate servo burst magnitudes can arise from...
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7397621 |
Servo pattern characterization on magnetic disks
In one embodiment, a surface analyzer system comprises a radiation targeting assembly to target radiation onto a surface, a reflected radiation collecting assembly that collects radiation reflected...
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7394612 |
Third order curve fit for head skew in a hard disk drive
A hard disk drive that utilizes a third order curve fit equation to generate a skew table for a head of a hard disk drive. The skew table is used to compensate for offset between a write element...
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7375916 |
Magnetic recording disk drive with multiple feedforward controllers for rotational vibration cancellation
A disk drive has multiple feedforward controllers for handling external disturbances, such as rotational vibration (RV), that have different external disturbance frequency spectra. Each feedforward...
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7372658 |
Correction table creation method for head position control, head position control method and disk device
A head position control system controls the position of the head by correcting the components synchronizing rotation of the disk from the head control amount, in which an adjusted gain to minimize...
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7365927 |
Eccentricity correction data recording method and recording medium having eccentricity correction data
An eccentricity correction data recording method, a disk-shaped recording medium, a head position control method and an information recording and reproducing apparatus are disclosed for effective...
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7345841 |
Disk drive using a disturbance sensor for disturbance frequency-identification and suppression
A magnetic recording disk drive has a disturbance sensor and a disturbance frequency identifier that are used to adjust the frequency of a peak filter as the disturbance frequency changes. The...
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7345842 |
Method and system for optimized servo track writing motor current profile to reduce written-in high-frequency repeatable runout track mis-registration
A system for reducing written-in high-frequency repeatable run-out track mis-registration occurring during writing of servo information onto a hard disk implementable in a hard disk drive is...
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7333288 |
Method and apparatus for single written-in Repeatable Run-Out correction function used in multi-stage actuation control of hard disk drive
RRO corrector function is formulated to partition the contribution of micro-actuator control from the other voice coil assembly contributions. Single stage actuation is supported by zeroing the...
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7330331 |
Repeatable runout estimation in a noisy position error signal environment
A system and method for estimating repeatable runout in a servo control system, such as a disc drive servo loop, is provided. The system includes a Kalman filter that is configured to receive...
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7330332 |
Method and apparatus for high-speed compensation of RRO error in hard disk drive
There are provided a method and apparatus for high-speed compensating repeatable run-out in a hard disk drive. The method includes a) obtaining a value of a position error signal (PES) of the hard...
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7328138 |
Method and system of measurement and optimization of noise in servo systems
Method and system of measuring and optimization of noise in a servo system. The method and system including features to optimize filtering otherwise reducing noise in the system so as to permit...
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7315430 |
Servo controller in magnetic disk drive
Embodiment of the invention inhibit an effect of repeatable runout errors without expanding servo data areas of the magnetic disk. With regard to low frequency components of positional information...
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7315431 |
Method to correct radial misposition of data tracks using stitched correction fields
A disk drive measures the radial misposition of tracks and repositions the tracks at regularly spaced intervals. Written in runout (WRO) in servo bursts is determined to calculate track spacing and...
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7304751 |
Apparatus and method for automatically measuring characteristics of a hard disk drive carriage arm
An apparatus and method for automatically measuring characteristics of a hard disk drive carriage arm. The method provides a first measuring device for automatically measuring a first side of a...
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7304819 |
Method for writing repeatable runout correction values to a magnetic disk of a disk drive
A method is disclosed for writing repeatable runout (RRO) correction values to a disk of a disk drive. The disk has distributed position information in a plurality of embedded servo sectors. The...
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7286317 |
Disk drive that compensates for repeatable runout of a disk based on measured timing between servo information and methods thereof
A disk drive includes a rotatable data storage disk, a transducer, an actuator, and a controller. The disk includes information and data tracks that are defined thereon. The transducer is...
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7286316 |
Method and data storage device for writing patterns onto recording disk
Embodiments of the invention efficiently conduct servo corrections for preventing error propagation during SSW. In an example of the present invention, a servo position signal generator generates a...
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7271977 |
Method to compensate for microjog error induced by localized track squeeze
A method of reducing microjog errors in a disk drive having a data recording disk with data tracks and a transducer head positionable on the tracks. The head includes a writer element offset from a...
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7268969 |
Repeatable timing mark position error correction in self-servowrite
The periodic component of a timing mark position error of a self-servo write pattern on a disk of a disk drive is determined based on measurements that are made of the timing mark position error at...
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7265932 |
Repetitive controller having reduced memory elements
A repetitive controller for suppressing periodic signals with half-wave symmetry includes a memory loop fed with a periodic signal of period NT and in which the memory size includes N/2 memory...
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7265933 |
Disk drive computing repeatable run out while actuator arm is pressed against crash stop
A disk drive is disclosed comprising a voice coil motor (VCM) for rotating an actuator arm about a pivot in order to actuate a head over a disk. The disk is rotated by a spindle motor, and a...
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7262930 |
Systems and methods for repairable servo burst patterns
The misplacement of a servo burst during a servowriting or self-servowriting process can be corrected by erasing and re-writing that burst. A servo pattern can be selected that has sufficient...
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7251098 |
Disk drive adjusting write clock frequency to compensate for eccentricity in disk rotation
A disk drive is disclosed that estimates a sinusoidal error in a wedge time period due to eccentricity in the disk rotating to generate eccentricity compensation values. During a write operation a...
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7251097 |
Written-in error compensation method for coherent repeatable runout
The present invention recognizes that induced RRO is coherent, i.e., the RRO has a large degree of repeatability from track to track. The present invention is a zero acceleration profile...
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7221533 |
Method and apparatus for servo information writing in a disk drive
A method of writing servo information for use in head positioning control on a disk medium incorporated in a disk drive, including executing the head positioning control based on original servo...
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7215501 |
Disk device, disk eccentricity control method, and recording medium
Weight factors corresponding to plural areas into which a disk is concentrically divided, respectively, are previously stored, and an amount of eccentricity control is calculated using the...
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7196864 |
Disk drive having a servo control system optimized for faster determination of repeatable runout correction values and related method
A disk drive is disclosed having a servo control system optimized for faster determination of repeatable runout (RRO) correction values. Each circumferential track on a magnetic disk exhibits total...
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7196865 |
Recording apparatus having discoid record mediums
A recording apparatus capable of securely reading out data for causing a head to follow along circular tracks set virtually. Therefore, on-track control along the virtual tracks is possible by the...
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7193809 |
Method of compensating for microjog error due to repeatable run-out
A process for continually compensating for the microjog error resulting from RRO. Typically, the 1F RRO is the most significant, but the method could be applied to the microjog error caused by RRO...
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7180693 |
Method and apparatus for maximum likelihood detection of data employing interpolation with compensation of signal asymmetry
A method and apparatus are disclosed for detecting data, such as a sample sequence read from a recording channel. Interpolation techniques are employed to generate one or more interpolated sample...
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7177112 |
Initial learn of adaptive feedforward coefficients
The present invention reduces the time required for coefficient convergence and thus improves time-to-ready. To that end, the present invention provides an initial learn—preferably...
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7167336 |
Method for providing variable gain, iterative embedded runout correction in a disk drive
A method for determining embedded runout correction (ERC) values using iteration and variable gain in a disk drive. A disk has a track written thereon, an ERC value is determined for a servo sector...
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7164550 |
Disk drive, positioning method for head, and servo system
Embodiments of the invention compensate for repeatable run-out errors without causing servo system instability. In one embodiment, HDD has a peak filter on a feedback route of a servo system. The...
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7161759 |
Self servo writing using servo burst edge errors for compound error correction
The present invention provides self-servo writing by which self-propagated servo pattern track shape errors are reduced or eliminated. The method includes providing first servo bursts on a first...
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7154700 |
Disk drive that stores time varying characteristics thereof with data from a host device and associated methods
A disk drive includes a rotatable data storage disk, a transducer, and a controller. The transducer is configured to write data on the disk. The controller is configured to receive data from a host...
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7151645 |
Interleaved repeatable runout estimation
A method and apparatus for reducing the effects of non-repeatable runout (NRRO) in the estimation of repeatable runout (RRO) in a disc drive is disclosed. PES information is a acquired in a way...
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7149048 |
Method and apparatus for improving spiral-based position correction system stability via kernel frequency component modification
The present invention is directed to a method and apparatus for improving spiral-based position correction system stability via kernel frequency component modification. In one embodiment, a disk...
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7145745 |
Multi-stage actuator disk drives, methods, and computer program products that compensate for repeatable runout based on estimated secondary actuator position
Methods of compensating for repeatable runout in a disk drive are provided. The disk drive includes a data storage disk, a transducer adjacent to the disk, a primary actuator for positioning the...
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7145304 |
Rotating storage media control loops having adaptive feed forward insertion of signals including harmonics
An adaptive feed forward controller inserts signals into control loops of an optical disc player and/or recorder at a frequency of the rotation of the disc and one or more harmonics thereof, while...
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7145746 |
Disk drive with adaptive control of periodic disturbances
A disk drive, such as a magnetic recording hard disk drive, has a head positioning servo control system that includes an improved repetitive controller included with the conventional feedback...
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7139145 |
Cluster-based defect detection testing for disk drives
Disclosed are techniques related to cluster-based defect detection testing for disk drives. A disk drive comprises a disk, a moveable head to scan the tracks of the disk, and a defect detection...
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7139149 |
Adapting compensation for repeatable runout of sectors based on tracked sector adaptation status
Methods, servo controllers, disk drives, and computer program products are provided for adapting compensation for repeatable runout (RRO) of sectors of a disk in a disk drive. RRO of a plurality of...
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7136253 |
Method and apparatus for providing multi-point position demodulation of a read head when using spiral-written servo information
The present invention is directed to a method and apparatus for providing multi-point position demodulation of a read head when using spiral-written servo information. In one embodiment, a disk...
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7133243 |
Burst position error data write method and magnetic disk unit
A magnetic disk unit writes, on a magnetic disk, a burst position error data which is used for correcting a positional error of a burst pattern which is used for correcting an error within one...
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7133244 |
Method and system for optimizing servo track writing motor current profile to reduce written-in high-frequency repeatable runout track mis-registration
A method for reducing written-in high frequency repeatable run out track mis-registration of a hard disk is described. The method includes adjusting the excitation frequencies away from mechanical...
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7123433 |
Method and apparatus for runout correction during self-servo writing
A disk drive self-servo writes on a storage disk. Servo bursts are self-written along a track using a transducer, a position error signal (PES) indicating repeatable runout due (RRO) for the servo...
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7119981 |
Method and apparatus for tracking radially-dependent repeatable run-out
An apparatus and method for tracking radially-dependent repeatable run-out in a disc drive having a servo loop for positioning a head over a rotating disc is provided. The disc includes multiple...
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7113362 |
Servo writing a disk drive by processing spiral tracks in an interleaved manner
A disk drive is disclosed having a disk comprising a plurality of spiral tracks, a head actuated over the disk, and control circuitry operable to process the spiral tracks in an interleaved manner...
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