| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 360051000 | Data clocking | 84 |
| 20080231984 | Apparatus and method to minimize amplitude variations associated with media/head response characteristics in servo writing of perpendicular magnetic recording - A servo writer that writes servo information onto a disk of a hard disk drive. The writing of the servo can be synchronized by a clock track that contains a clock read back signal. The clock read back signal is differentiated by a differentiator circuit. A clamping circuit clamps the clock read back signal to minimize signal ringing, undershoot and overshoot phenomena in the signal. | 09-25-2008 |
| 20080304173 | MAGNETIC RECORDING DISK DRIVE WITH PATTERNED MEDIA AND SYSTEM FOR CLOCKING WRITE DATA - A system and method accurately clocks write data to the discrete data blocks in a patterned media disk drive. The precise time intervals between successive timing marks in the data tracks are measured by a timing mark detector that counts the integer number of write clock cycles between successive timing marks and the fractional part of a write clock cycle by detecting the phase difference between a timing mark and a reference signal. The resulting timing error is output to a write clock compensator. The write clock is capable of generating equally spaced primary phases and phases intermediate the primary phases. The compensator includes a phase rotator that controls which write clock phase is selected for output. The value in a phase register of the compensator is used to control the phase rotator to advance or retard the write clock phase, and thus to adjust its frequency and phase so as to be synchronized for writing to the data blocks. | 12-11-2008 |
| 20090002865 | Zone Based Timing Recovery For Bit Patterned Media - A method includes: producing a bit detection signal in response to a plurality of islands located in a plurality of zones of a bit patterned media, processing the bit detection signal to produce a synchronization signal, wherein the processing is dependent on characteristics of the islands in the zone containing the plurality of islands, and using the synchronization signal to control timing of writing to the bit patterned media. The synchronization signal can also be used to control timing of reading from the bit patterned media. | 01-01-2009 |
| 20090002866 | ADJUSTMENT OF READ/WRITE CLOCK EDGE TIMING - Apparatus and methods are disclosed that adjust the phase of a read/write clock signal. The read/write clock signal may be used in a data storage apparatus to regulate reading/writing on a data storage media. An apparatus includes an adjustment circuit that adjusts phase of an edge of a read/write clock signal based on the timing of information that is read from a data storage media. Another apparatus includes a servo circuit and a read/write channel circuit. The servo circuit generates a leading edge transition of a servo gate signal in response to a signal indicating that a read/write transducer is approaching a start of a servo wedge. The read/write channel circuit generates a trailing edge transition of the servo gate signal in response to occurrence of a defined time delay following the transducer reading a servo address mark from the servo wedge. | 01-01-2009 |
| 20090002867 | Alternative Sensors For Tracking And Timing In Bit Patterned Media - An apparatus includes a bit patterned magnetic storage media, a write transducer positioned adjacent to the bit patterned magnetic storage media, a write driver coupled to the write transducer to deliver write pulses to the write transducer, an optical sensor for producing a bit pattern signal, and a timing recovery circuit for producing a synchronization signal in response to the bit pattern signal, wherein the timing of the write pulses is adjusted in response to the synchronization signal. | 01-01-2009 |
| 20090052075 | Systems and Methods for Improved Synchronization Between an Asynchronously Detected Signal and a Synchronous Operation - Various embodiments of the present invention provide systems and methods for synchronizing data processing. As one example, a method for synchronizing data processing is disclosed that includes receiving a data input, and sampling the data input at a sample period to generate a sample set. A first pattern is received and a first periodic boundary associated with the first pattern is identified. In one particular case, the first pattern is a preamble pattern included as sector data on a storage medium, and the first periodic boundary is a 4T boundary. Further, a second pattern is detected in the sample that is used to establish a second periodic boundary. In one particular case, the second pattern is a SAM pattern included as sector data on a storage medium, and the second periodic boundary is a 1T boundary. Based at least in part on the first periodic boundary and the second periodic boundary, a time to transmit or assert a data-found signal is determined. | 02-26-2009 |
| 20090080101 | SIGNAL GENERATOR WITH ADJUSTABLE FREQUENCY - Frequency of an oscillating signal is temporarily adjusted to adjust frequency and/or phase of an output signal. For example, the frequency of the oscillating signal may be adjusted for a very short period of time to adjust the phase of the output signal. In addition, the frequency of the oscillating signal may be temporarily adjusted in a repeated manner to adjust the effective frequency of the output signal. In some aspects the frequency of the oscillating signal is adjusted by reconfiguration of reactive circuits associated with an oscillator circuit. | 03-26-2009 |
| 20090091854 | Write timing system for hard disk drives with bit patterned media - A hard disk drive with a patterned disk that has a plurality of data fields. Each data field includes a sync field and a plurality of sync marks. Data is written onto the patterned disk in accordance with a write clock. The write clock is generated and synchronized by the sync field and the sync marks. The sync marks are dispersed throughout the data field so that the write clock is resynchronized as data is written onto the field. | 04-09-2009 |
| 20090109564 | Low-power read channel for magnetic mass storage systems - An improved mass storage system having a read channel adapted to store in a FIFO memory digitized analog samples of data symbols read from a disk, the buffered digitized samples being processed by digital circuitry that may be operated at a slower speed than the maximum symbol rate from the disk. In one embodiment, the read channel has an analog portion that processes analog signals from a read head and includes an ADC for converting the processed analog signals into digital samples in response to a first clock; a FIFO storing therein the digital samples in response to the first clock and reading out the stored digital samples in response to a second clock; and a detector, in response to the second clock, detecting the digital samples from the FIFO into digital data. The maximum frequency of the first clock is less than the maximum frequency of the second clock. | 04-30-2009 |
| 20090168218 | DISK DRIVE DEVICE AND SERVO WRITE METHOD - According to one embodiment, a servo write module is configured to write radial servo patterns on the disk media using a first spiral servo pattern of the spiral servo patterns as a base pattern for tracing, to detect a shift amount of a sync mark position in each of other spiral servo patterns with respect to a sync mark position in the first spiral servo pattern, and to adjust, when the base pattern is switched from the first spiral servo pattern to a second spiral servo pattern of the spiral servo patterns, a phase of the servo write clock based on the detected shift amount corresponding to the second spiral servo pattern. | 07-02-2009 |
| 20090237826 | DATA STORAGE APPARATUS - A data storage apparatus includes: a medium for storing data including sectors, each of the sectors including a synchronization mark indicating the data start position in each of the sectors; a memory for storing types of synchronization marks stored in the sectors; and a processor for executing a process including receiving a write request, reading out a synchronization mark type from the memory, overwriting data, a new synchronization mark into the sector, and the new synchronization mark into the memory, receiving a read request, reading out the synchronization mark and the data from one of the sectors, reading out the type of the synchronization mark from the memory, and determining whether correct data is read out from the sector by matching the type of the synchronization mark between read out from the sector and read out from the memory. | 09-24-2009 |
| 20090244760 | MAGNETIC STORAGE CONTROL APPARATUS, MAGNETIC STORAGE CONTROL METHOD, AND MAGNETIC STORAGE APPARATUS - A magnetic storage control apparatus for controlling a magnetic storage apparatus that uses a recording medium having a plurality of reference signals on its track and having a data area between the reference signals. The apparatus includes: a measurement section that reproduces the reference signal in a predetermined track of the recording medium and measures, for each data area, the time for a head to scan the data area to obtain a measurement value; a calculation section that calculates a setting value concerning the frequency of a recording clock used in data recording based on the measurement values of a plurality of data areas obtained by the measurement section; and a generation section that generates the recording clock based on the measurement values obtained by the measurement section and setting value calculated by the calculation section. | 10-01-2009 |
| 20090268331 | HARD DISK DRIVE AND SERVO TRACK WRITING SYSTEM FOR THE SAME - A hard disk drive includes a housing including a base member and a cover member, a spindle motor disposed in the housing, a data storage disk disposed on the spindle motor, an actuator disposed in the housing to move a read/write head to a position on the data storage disk, a clock signal providing unit disposed on the data storage disk to provide a clock signal of the data storage disk, a position signal providing unit disposed on the actuator to provide a position signal of the actuator, and first and second windows disposed in the housing to correspond to the clock signal providing unit and the position signal providing unit. | 10-29-2009 |
| 20090296255 | PHASE ADJUSTING DEVICE, MAGNETIC STORAGE MEDIUM, AND STORAGE DEVICE - A magnetic storage medium such as a BPM includes a plurality of magnetic dots for writing and reproducing data disposed in a magnetically separated manner so as to be spaced a predetermined distance in a down-track direction and a plurality of tracks concentrically disposed so that the magnetic dots are disposed in a magnetically separated manner. In the BPM, a phase-adjusting track is disposed in an arbitrary track among the tracks. On the phase-adjusting track, phase detection dots disposed in a down-track direction to allow writing and reproduction of phase detection data and blank bits providing a predetermined phase difference in a down-track direction to next successive phase-detecting dots are alternately disposed in a successive manner. | 12-03-2009 |
| 20100020429 | Converting Timing Errors Into Symbol Errors to Handle Write Mis-Synchronization in Bit-Patterned Media Recording Systems - A method includes: writing data to a bit-patterned media at times determined by a clock having a period that is offset from a bit island period by a fixed offset to create one insertion or one deletion approximately within a predetermined number of bit islands, reading the data, and correcting the read data using error correction. An apparatus that implements the method is also provided. | 01-28-2010 |
| 20100073800 | RECOVERING SERVO INFORMATION FROM A SYNCHRONOUS SERVO CHANNEL - Provided are a method, servo channel, and tape drive for recovering servo information from a synchronous servo channel. An interpolator reads samples of a servo signal obtained from a servo reader at a rate of one servo sample per clock interval, to produce up to M interpolated servo samples per clock interval. A first buffer buffers interpolation time instants at which the interpolator generates interpolated servo samples. The interpolated servo samples are buffered in a second buffer and the interpolated servo samples are outputted from the second buffer to a correlator to produce correlation signal samples. | 03-25-2010 |
| 20100073801 | MAGNETIC RECORDING DEVICE, CONTROL DEVICE, AND MAGNETIC RECORDING DEVICE CONTROL METHOD - A magnetic recording device includes: a magnetic recording medium including a write-synchronization region and a data region; a correction-value-storage unit configured to store therein a phase-correction value for correcting a phase of the write clock; a reading unit configured to read out a signal from the magnetic recording medium; a write-clock generator configured to generate the write clock based on a write-reproduction signal which is a signal read out from the write-synchronization region by the reading unit; a phase-correction unit configured to correct the phase of the write clock generated by the write-clock generator based on the phase-correction value stored in the correction-value-storage unit; and a data acquisition unit configured to acquire data included in a data-reproduction signal which is a signal read out from the data region by the reading unit based on a clock that is generated by correcting the phase by the phase-correction unit. | 03-25-2010 |
| 20100079891 | TRACK-ADAPTED DATA CLOCKING - A method for writing data to a tape at multiple rates for simultaneously creating data tracks having differing linear data densities, according to one embodiment, includes passing a tape over a head, the head having an array of writers thereon; receiving incoming data; mapping the data to a two dimensional array corresponding to the array of writers; clocking some of the mapped data to a first writer in the array of writers at a first rate; and clocking some of the mapped data to a second writer in the array of writers at a second rate different than the first rate. | 04-01-2010 |
| 20100110573 | SYNCHRONOUS WRITING WITH TIMING ERROR DETECTION IN BIT PATTERNED MEDIA DISK DRIVES - A hard disk drive that includes a head that is coupled to a disk. The disk drive further includes a comparator circuit that is coupled to the head. The comparator circuit receives a synchronization signal and a write clock. The comparator generates a write error signal if a comparison of the synchronization and write clock signals exceeds a threshold. The write error signal can inhibit a write operation or cause a rewrite of data. | 05-06-2010 |
| 20100110574 | TESTING STORAGE SYSTEM ELECTRONICS USING LOOPBACK - A system includes a hard disk controller module configured to control a hard disk. A read channel device is in communication with the hard disk controller module via a read bus and a write bus. The read channel device includes a loopback circuit configured to selectively loop back the write bus to the read bus. The read channel is configured to generate a write clock for the hard disk controller module to write data on the write bus. The read channel is configured to generate a read clock for the hard disk controller module to read the data on the read bus. The write clock is independent of the read clock. | 05-06-2010 |
| 20100118426 | WRITE CLOCK CONTROL SYSTEM FOR MEDIA PATTERN WRITE SYNCHRONIZATION - A write clock control system comprises a clock controller that determines a phase offset based on a phase difference between a write clock signal and a media pattern corresponding to a given timing synchronization field being read, and a phase interpolator that produces an updated write clock signal by updating the phase of the write clock signal in accordance with control signals that are based on the phase offset signal. | 05-13-2010 |
| 20100118427 | ELIMINATING SECTOR SYNCHRONIZATION FIELDS FOR BIT PATTERNED MEDIA - Clock synchronization techniques are described for data storage media, particularly for the tolerances of efficient use of bit patterned media (BPM) capacity. In particular, techniques are described where position of a read-write head and timing of a write and/or read clock is determined within a fraction of a dot of the underlying media. The techniques obviate the requirement for the fields conventionally written preceding a data sector to provide bit synchronization and symbol framing (sector synchronization fields). | 05-13-2010 |
| 20100118428 | INTERSPERSED PHASE-LOCKED LOOP FIELDS FOR DATA STORAGE MEDIA SYNCHRONIZATION - Techniques are described for providing media-referenced timing for operations on a data storage medium. In particular, Phase-Locked Loop (PLL) synchronization fields may be interspersed within data fields of the medium and may be read to obtain timing measurements. The PLL fields are illustratively pre-recorded at predetermined intervals on the medium and have a fixed number of dots of the bit patterned medium between the PLL fields. Phase and frequency of a write clock may be controlled based on the read PLL fields to translate the timing measurements from the PLL fields into phase and frequency corrections to synchronize the write clock to the data storage medium, | 05-13-2010 |
| 20100118429 | REDUCED READ/WRITE TRANSITION OVERHEAD FOR STORAGE MEDIA - A technique is described for reducing overhead in a magnetic medium utilizing interspersed timing synchronization fields. In particular, a reader reads timing synchronization fields interspersed within data fields of the medium to obtain timing measurements. The reader is separated from a writer by a distance greater than a distance of the reader to traverse a select timing synchronization field. As such, the writer may perform a direct current (DC) write to the medium to suspend transitional write operations while the reader is reading the select timing synchronization field, and/or while the writer is over a unipolar field (e.g., a timing synchronization field). | 05-13-2010 |
| 20100134913 | FREQUENCY CONTROL APPARATUS AND STORAGE DEVICE - According to one embodiment, a frequency control apparatus includes an eccentric component storage module, a frequency correction amount calculating module, and an oscillator control module. The eccentric component storage module stores in advance an eccentric component calculated by a discrete Fourier transform of the number of clock signals measured for each servo frame. The frequency correction amount calculating module calculates the number of clock signals corresponding to the servo frame based on the eccentric component stored in the eccentric component storage module and calculates a frequency correction amount corresponding to the servo frame based on the number of clock signals. The oscillator control module controls the operation of a frequency oscillator such that a frequency for oscillating a clock signal in the frequency oscillator is adjusted according to the frequency correction amount calculated by the frequency correction amount calculating module. | 06-03-2010 |
| 20100142078 | Systems and Methods for Memory Efficient Repeatable Run Out Processing - Various embodiments of the present invention provide systems and methods for low overhead disk wobble compensation. As an example, a method for performing synchronous wobble compensation processing is disclosed. The method includes providing a medium that includes a servo data region and a user data region. The servo data region includes a clock recovery pattern and a location pattern. A detectable pattern is written to the user data region a known number of bit periods from the location pattern. The detectable pattern is read back, and a fractional processing delay is calculated. Based at least on the fractional processing delay and a known number of bit periods from the location pattern to the end of the servo data region, a wobble compensation pattern is written an integral number of bit periods from the location pattern. | 06-10-2010 |
| 20100149675 | Skip Block Writing For Bit Patterned Media Write Synchronization - A method for synchronizing writing to a bit patterned media includes: reading bits from skipped blocks on the bit patterned media, using timing of bits read from the skipped blocks to update a write clock, and writing request data to physical blocks on the bit patterned media, interleaved with the skipped blocks. An apparatus that operates in accordance with the method is also provided. | 06-17-2010 |
| 20100157459 | Systems and Methods for Controlling Data Equalization - Various embodiments of the present invention provide systems and methods for performing data equalization. For example, various embodiments of the present invention provide data equalization circuits that include an equalization circuit and a transition adjustment circuit. The equalization circuit receives a series of at least two original data bits and replaces at least one of the two original data bits with an equalization pattern including two or more equalization bits. The original data bits correspond to an original data clock, and the two or more equalization bits correspond to an equalization data clock. The transition adjustment circuit is operable to modify an occurrence of a transition from one logic state to another logic state within the equalization pattern on a sub-equalization data clock basis. | 06-24-2010 |
| 20100202079 | WRITE SYNCHRONIZATION PHASE CALIBRATION FOR STORAGE MEDIA - A technique is described for write synchronization phase calibration for storage media (e.g., bit patterned media). In one embodiment, a calibration write clock signal may be generated at a frequency offset from a nominal dot frequency of a bit patterned storage media. A periodic signal that was written to the media synchronous to the calibration write clock signal may then be read and mixed with a reference periodic signal at the nominal dot frequency to obtain a difference signal. This difference signal may be demodulated to determine a phase correction for write synchronization to the media. | 08-12-2010 |
| 20100238578 | METHOD FOR GENERATING WRITE CLOCK SIGNAL IN MAGNETIC DISK DRIVE - According to one embodiment, a write clock generator writes data to bits in a magnetic recording medium based on a write clock signal with a phase obtained by delaying the phase of a reference write clock signal. The write clock generator detects the amplitude of a read signal for the written data. The write clock generator repeats these operations with a phase delay varied. The write clock generator decides an optimum phase delay based on the amplitude detected for each phase delay. | 09-23-2010 |
| 20100259845 | THERMALLY-ASSISTED MAGNETIC RECORDING HEAD AND THERMALLY-ASSISTED MAGNETIC RECORDING METHOD - A head capable of favorite thermally-assisted magnetic recording without depending on the use of a near-field light generator is provided. The head comprises a write head element formed on the trailing side from a waveguide and comprising a first main pole. The first main pole and the waveguide are opposed to each other through a first clad layer, and a second clad layer is provided on a rear side from the first main pole. This gives that the end surface of the waveguide can be placed much close to the end surface of the first main pole apart by only a thickness of the first clad layer. As a result, the end surface of the first main pole can apply a sufficient intensity of write field to the intensity center and its vicinity of the light spot formed on the magnetic recording layer. | 10-14-2010 |
| 20100302669 | TRANSDUCER DESIGN WITH A SENSOR CLOSE TO WRITE POLE - A magnetic device includes a read sensor, a writer and a synchronization sensor. The magnetic device is configured for writing information to and reading information from a magnetic medium that includes a plurality of discrete magnetic bits. The writer includes a write element, a first return element magnetically coupled to the write element, and a second return element magnetically coupled to the write element. The write element is positioned in between the first and second return elements. The synchronization sensor is located adjacent to the write element of the writer in a closely spaced arrangement, and is configured to generate a signal as a function of a sensed magnetic bit. The signal is used to position the writer element relative to the sensed magnetic bit. | 12-02-2010 |
| 20100328804 | MAGNETIC DISK STORAGE DEVICE AND METHOD CONTROLLING OF MAGNETIC DISK STORAGE DEVICE - According to one embodiment, a magnetic disk storage device includes a magnetic disk, a head, a clock generator, an estimating module, and a controller. The magnetic disk includes a servo area and a corresponding data area, and has a surface divided into zones in the radial direction. The basic frequency varies in the servo area depending on the zones. The head is driven to read a signal from the magnetic disk. The clock generator generates a clock signal for decoding a signal read from the data area corresponding to the servo area based on a signal read from the servo area. The estimating module estimates the position of the servo area in the radial direction, from which the head reads a signal next. The controller controls the clock generator to generate a clock signal of the basic frequency before the head reaches the servo area based on the estimated position. | 12-30-2010 |
| 20110032632 | TIMING RECOVERY DETECTOR - A timing detector adapted for timing recovery on a read-channel is disclosed to improve signal quality of an input signal and maintain a small loop latency. The timing detector selects bits within the input signal that are high quality for timing recovery and discards bits that are low quality. The selected bits are used to synchronize phase and frequency of a bit sampler with a read-back analog signal. High-pass and low-pass analysis filters may split the input signal into high-frequency and low-frequency sub-bands and equalizers may re-shape the sub-bands. High-pass and low-pass synthesis filters may construct an output signal from the high-frequency and low-frequency sub-bands. Scaling factors may correct for signal and disturbance variations in the sub-bands. A comparator may eliminate sampled bits within the detector signal that have a magnitude less than a threshold and assign a common magnitude to sampled bits that meet or exceed the threshold. | 02-10-2011 |
| 20110038073 | Using Readback Signals to Estimate Radial Location on a Rotating Storage Device - Approaches for estimating the operating radius of a head in a hard-disk drive. These approaches may be used in a constant or approximately constant density servo scheme. Statistics, which describe the proportion of high frequency values to low frequency values in a readback signal read by the read/write head of a persistent storage medium, such as a hard-disk drive (HDD), are maintained. An estimated location for the read/write head using the statistics is determined. The estimated location may be expressed as an estimated operating radius, which is an estimated distance from the center of the magnetic-recording medium to a current position of the read/write head. Based on the estimated location of the read/write head, an estimated clock frequency for a readback channel to use in reading the servo data stored on the magnetic recording medium is determined. The readback channel reads the servo data using the estimated clock frequency. | 02-17-2011 |
| 20110102929 | DISK DRIVE AND METHOD OF TIMING CONTROL FOR SERVO-DATA DETECTION - A method of timing control for servo-data detection in a disk drive. The method includes retrieving a plurality of servo sectors arranged discretely in a circumferential direction of a disk and measuring time intervals between servo sectors. The method also includes determining in which zone of a plurality of preset zones each of the measured time intervals is included. Moreover, the method also includes determining variations in time intervals from the zones of a plurality of previous time intervals, and modifying timing for servo-sector detection if variations in time intervals are within a preset range. | 05-05-2011 |
| 20110205657 | SYNCHRONIZATION OF SYMMETRIC TIMING BASED SERVO BURSTS - Timing based servo bursts of servo frames, in which the frames are arranged to be symmetric with the same number of servo stripes in each burst of a frame, are synchronized by shifting selected bits. For example, servo frames are arranged with four servo bursts with an equal number of servo stripes in each burst, the servo frames comprising two symmetric sub-frames, each sub-frame comprising two bursts of servo stripes that are parallel to each other within a burst, and the bursts are non-parallel with respect to each other; each servo burst is arranged to comprise at least one reference servo stripe; and each servo burst is arranged to comprise at least one shifted servo stripe, wherein the shift is in the same longitudinal direction with respect to at least one reference servo stripe for each burst of a frame and the opposite longitudinal direction for bursts of sequentially adjacent frames. | 08-25-2011 |
| 20110216434 | TIMING ALTERNATIVE INTERVALS WITHIN A TIMING BASED SERVO BAND - An alternative time interval is taken of a timing based servo band to determine lateral position of a servo read head. The servo band is arranged in a sequence bursts with non-parallel servo stripes in sequentially adjacent sub-frames of a linear tape. The timing intervals comprise at least a first time interval (A) between a first pair of non-parallel servo stripes of a sub-frame; and an alternative time interval (C) between a pair of non-parallel servo stripes intermediate the first time intervals (A), the alternative interval servo stripes of sequentially adjacent sub-frames comprising a second servo stripe of the first pair, and a first servo stripe of a sequentially succeeding first pair. Position signals are ratios involving the first and second time intervals. | 09-08-2011 |
| 20110292535 | METHODS AND APPARATUS FOR SYNCHRONIZATION MARK DETECTION BASED ON A POSITION OF AN EXTREME DISTANCE METRIC - Methods and apparatus are provided for detection of a synchronization mark based on a position of an extreme distance metric. A synchronization mark is detected in a received signal by computing a distance metric between the received signal and an ideal version of the received signal expected when reading the synchronization mark, wherein the distance metric is computed for a plurality of positions within a search window; determining a substantially extreme distance metric within the search window; and detecting the synchronization mark based on a position of the substantially extreme distance metric. The distance metric can comprise a sum of square differences or a Euclidean distance between the received signal and the ideal version of the received signal. | 12-01-2011 |
| 20120113539 | SKEW COMPENSATION SIGNAL - The relative trajectory of a transducer head over bit-patterned media (BPM) may be skewed with respect to a down-track direction on the media (i.e., skew error). In order to resolve the skew error, the presently disclosed technology measures the skew error without adding additional patterning on the media. A detector circuit detects a sequential series of data bits on a storage media. The sequential series of data bits alternate between at least two tracks on the storage media. The sequential series of data bits are sent to a timing circuit, which sets a time stamp indicating when each data bit is received using, for example, a delay chain or a voltage ramp. A time elapsed between receiving a first data bit, a second data bit, and a third data bit is tracked. Transducer head skew is adjusted based on a signal containing the time elapsed between the bits. | 05-10-2012 |
| 20120134044 | MAGNETIC DISK DEVICE, SIGNAL PROCESSING CIRCUIT, AND SIGNAL PROCESSING METHOD - According to one embodiment, a signal processing circuit processes a signal read from a magnetic disk including a servo region and a user data region, the servo region including a servo address mark, the user data region including a data sector, and includes a counter and a gate controller. The counter is configured to count a first clock when having detected the servo address mark based on the signal read from the magnetic disk. The gate controller is configured to generate a pulse for locating the data sector in synchronization with a second clock when the counter counts a first value. | 05-31-2012 |
| 20120147493 | Phase Calibration System for Disk Drives - A method and disk drive for calibrating a phase of a clock in the disk drive. The phase of the clock in the disk drive is changed such that a rate of change for the phase is substantially constant. A pattern of data is written to a magnetic material in the disk drive after the rate of change for the phase becomes substantially constant and while changing the phase of the clock. A selected phase of the clock at which the pattern of data that is written on the magnetic material has a desired quality is identified using the rate of change for the phase, a first point in time at which a timing mark on the magnetic material is read, a second point in time at which the timing mark is read, and a third point in time at which the pattern of data has the desired quality. | 06-14-2012 |
| 20120194938 | METHOD OF WRITING INITIAL CLOCK PATTERNS AND MAGNETIC DISK DRIVE - According to one embodiment, a method of writing initial clock patterns to a disk in a magnetic disk drive is disclosed. The method can write a first timing mark in a location on a circumference of a disk using a head based on a first clock signal corresponding to a frequency of oscillation of an oscillator. The method can adjust the frequency of oscillation of the oscillator or a rotational speed of a spindle motor by detecting, as a first timestamp, a time interval at which the first timing mark is read by the head from the disk so as to coincide with a second timestamp targeted by the first timestamp. In addition, the method can write the initial clock patterns to the disk based on a second clock signal corresponding to the adjusted frequency of oscillation or the adjusted rotational speed after the adjustment. | 08-02-2012 |
| 20120194939 | PATTERNED MEDIUM INSPECTION METHOD AND INSPECTION APPARATUS - A patterned medium inspection method according to the present invention includes a timing computation process including a read process reading the reproduced signal of a patterned medium under inspection and a computation process computing the signal interval values from the patterned medium reproduced signal read in the read process, and a judgment process judging the quality of the patterned medium using the reproduced signal interval values computed in the computation process. | 08-02-2012 |
| 20120229929 | MAGNETIC RECORDING MEDIUM AND MAGNETIC READING APPARATUS - According to one embodiment, a magnetic recording medium includes: a data area where a plurality of first magnetic dots are placed at predetermined positions to record information, the data area being formed on a surface of the magnetic recording medium; a servo area where a plurality of second magnetic dots for specifying the positions of the first magnetic dots are placed at predetermined positions, the servo area being formed on a surface of the magnetic recording medium; and servo address marks being doubly formed in the servo area, and subdivision being performed while boundary positions of second magnetic dots of one of the servo address marks and boundary positions of second magnetic dots of another one of the servo address marks are different from each other in a radial direction. | 09-13-2012 |
| 20120293885 | POSITION DEMODULATOR AND POSITION DEMODULATION METHOD - According to one embodiment, a position demodulator includes a demodulator, a phase corrector, and a position demodulating module. The demodulator demodulates a first demodulated signal and a second demodulated signal having a phase difference of 90 degrees from the first demodulated signal as a result of discrete Fourier transform operation on a read signal of a null servo pattern recorded in a servo area of a medium read out by a head. The phase corrector carries out correction to tilt respective vectors of the first demodulated signal and the second demodulated signal represented on a phase plane by a predetermined angle. The position demodulating module demodulates a positional signal for determining the position of the core of the head based on the first demodulated signal and the second demodulated signal corrected by the phase corrector. | 11-22-2012 |
| 20120293886 | TAPE STORAGE DEVICE, DATA WRITING METHOD, AND PROGRAM - A tape drive receives multiple write requests for data pieces and a synchronization request corresponding to the write requests from a device, performs a synchronization process, and returns a completion status of the synchronization request. The tape drive includes a write controller that stores data pieces transferred from the device in the buffer, according to a first write request, receives a first synchronization request and then a subsequent write request for at least one data piece, and returns the completion status when processing for the first synchronization request is completed and the subsequent write request is received with a command queuing function. | 11-22-2012 |
| 20130003214 | Systems and Methods for Inter-Track Alignment - Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is discussed that includes: a servo address mark count circuit, a user sync mark count circuit, and an offset calculation circuit. The servo address mark count circuit is operable to provide: a first count corresponding to a first servo address mark within a first track of a storage medium, a second count corresponding to a second servo address mark within the first track, a third count corresponding to a third servo address mark within a second track of the storage medium, and a fourth count corresponding to a fourth servo address mark within the second track. The user sync mark count circuit is operable to provide: a fifth count corresponding to a first user sync mark within the first track, and to provide a sixth count corresponding to a second user sync mark within the second track. The offset calculation circuit is operable to calculate an offset between the first track and the second track based at least in part on the first count, the second count, the third count, the fourth count, the fifth count, and the sixth count. | 01-03-2013 |
| 20130003215 | WRITING A REFERENCE PATTERN TO BIT PATTERNED MEDIA - A given reference pattern is written on bit patterned media that has an initial reference pattern already disposed thereon. A write phase and frequency is detected based on the initial reference pattern and the given reference pattern is written on the bit patterned media at the detected write phase and frequency. | 01-03-2013 |
| 20130010383 | PATTERNED MEDIA WITH AN ALTERNATING SERIES OF CONCENTRIC SERVO ZONES AND OVERLAP ZONES - Embodiments described herein provide for patterned media concentric zones with an alternating series of concentric servo zones and overlap zones. The overlap zones facilitate the writing of servo data between servo zones of different servo frequency. The overlap zones may be dual frequency zones. The dual frequency zones have a first set of overlap patterns with the substantially identical pattern as the bordering lower frequency servo zone and a second set of overlap patterns with the substantially identical pattern as the bordering higher frequency servo zone. A bootstrap zone can be included near the inner diameter to assist initial servo writing. Alternatively the overlap zones are bootstrap zones. Such bootstrap zones have both bootstrap patterns and overlap patterns, the overlap patterns have the substantially identical pattern as a bordering servo zone. Bootstrap patterns only require DC magnetization for servo operability. | 01-10-2013 |
| 20130021690 | Systems and Methods for User Data Based Fly Height Calculation - Various embodiments of the present invention provide systems and methods for calculating and/or modifying fly height. For example, a circuit for calculating fly height is disclosed that includes: a first pattern detector circuit, a second pattern detector circuit, a first pattern fly height calculation circuit, a second pattern fly height calculation circuit, a first averaging circuit, a second averaging circuit, and a combining circuit. | 01-24-2013 |
| 20130077188 | Systems and Methods for Controlled Wedge Spacing in a Storage Device - Various embodiments of the present invention provide systems and methods for data processing. For example, some embodiments of the present invention provide clock generation systems that include: a first clock multiplier circuit, a second clock multiplier circuit, a modulus accumulator circuit, and a data clock phase control circuit. The first clock multiplier circuit is operable to multiply a reference clock by a first multiplier to yield a first domain clock, and the second clock multiplier circuit is operable to multiply the reference clock by a second multiplier to yield a second domain clock. The modulus accumulator circuit is operable to yield a value indicating a fractional amount of the second domain clock that an edge of the second domain clock is offset from a trigger signal. The data clock phase control circuit is operable to phase shift the second domain clock by a phase amount corresponding to the fractional amount. | 03-28-2013 |
| 20130128376 | METHOD AND A DEMODULATOR FOR DEMODULATING A POSITION ERROR SIGNAL FROM A READBACK SERVO SIGNAL - According to embodiments of the present invention, a method for demodulating a position error signal from a readback servo signal having a first frequency associated with a first servo track of a storage medium and a second frequency associated with a second servo track adjacent to the first servo track is provided. The method includes sampling the readback servo signal at successive time instants to provide a sequence of samples, computing a Discrete Fourier Transform based on the sequence of samples, and providing a measurement indicative of the position error signal based on the Discrete Fourier Transform. According to further embodiments of the present invention, a demodulator is also provided. | 05-23-2013 |
| 20130135766 | STORAGE DEVICE HAVING CLOCK ADJUSTMENT CIRCUITRY WITH FIRMWARE-BASED PREDICTIVE CORRECTION - A hard disk drive or other disk-based storage device comprises a storage disk, a read/write head configured to read data from and write data to the storage disk, and control circuitry coupled to the read/write head and configured to process data received from and supplied to the read/write head. The control circuitry comprises clock adjustment circuitry configured to generate a control signal for adjusting a parameter of a clock signal based at least in part on timing information obtained by detecting a timing pattern on a surface of the storage disk. The control signal is generated utilizing at least a predictive correction control loop, with the clock adjustment circuitry comprising predictive control firmware that implements at least a portion of the predictive correction control loop. | 05-30-2013 |
| 20130141811 | Disk drive with write clock frequency compensation for external vibration disturbance - A disk drive is described that uses a vibration sensor to generate a compensating feed-forward control signal to synchronize the write clock frequency with the modulated data island frequency. A linear vibration sensor is positioned with its sensitivity axis aligned with the tangential direction of a track at the radial position of the write head. The tangential component of the external linear vibration is measured by the sensor. The feed-forward control signal derived from the linear vibration sensor modifies the control voltage input to VCO (voltage controlled oscillator) in the write clock generator to adjust the write clock frequency to compensate for the modulated data island frequency caused by the tangential component of the linear vibration. | 06-06-2013 |
| 20130141812 | WRITE CLOCK SYNCHRONIZATION APPARTUS FOR MAGNETIC RECORDING DISK DRIVES WITH PATTERNED MEDIA - A write clock generator for use in writing data to a rotating patterned magnetic media disk is disclosed. The generator includes a magnetic read head for generating a succession of servo signals representative of succession of servo magnetization patterns detected from a corresponding succession of arcuate sectors along a circular data track on the disk. A preamble processor generates a corresponding succession of sector pair signals representative of the lengths of adjacent sectors along the data track on a rolling pair-wise basis. A next sector length predictor processor determines for a succession of pairs of sectors, a length ratio of the lengths of the sectors in the respective pairs of sectors. A clock generator generates a periodic clock for each sector of the succession of sectors, wherein the clock rate associated with a current sector has an associated phase deviation relative to a clock rate associated with a previous sector, which is proportional to the length ratio for the current sector and the previous sector. | 06-06-2013 |
| 20130155541 | Detector Pruning Control System - Various embodiments of the present invention provide apparatuses, systems and methods for data detection in a detector with a pruning control system. For example, a data detector is disclosed that includes a first set of counters operable to distinguish prunable data from non-prunable data in the data detector, a second set of counters operable to generate initial values for the first set of counters, and a prune control signal generator operable to generate a prune control signal based on the first set of counters. The second set of counters is operable to generate the initial values at least in part before a syncmark is detected in a data sector. The initial values are used to initialize the first set of counters when the syncmark is detected in the data sector. The prune control signal controls whether the data detector is allowed to prune a trellis. | 06-20-2013 |
| 20130182349 | INFORMATION RECORDING APPARATUS AND INFORMATION WRITING METHOD - According to one embodiment, there is provided an information recording apparatus that writes information onto a magnetic recording medium including a plurality of fine magnetic grains. The information recording apparatus includes a random number generation unit, a modulation unit, and a processing unit. The random number generation unit generates a random number bit value. The modulation unit modulates a period of a basic clock according to the random number bit value generated, and generates a modulated clock. The processing unit writes or reads information with respect to the magnetic recording medium in synchronization with the modulated clock generated. | 07-18-2013 |
| 20130182350 | MAGNETIC DISK DRIVE AND METHOD FOR SERVO BURST DATA CORRECTION - According to one embodiment, a magnetic disk includes a plurality of tracks each having a plurality of servo frames with servo burst data and repeatable runout correction data written thereto. The repeatable runout correction data includes a pattern repeated at a predetermined period and is written so that beginning of write is delayed by a time corresponding to a correction amount with respect to a base point corresponding to a synchronization timing position in the servo frame. A detector detects a phase delay amount corresponding to a time elapsed until the repeated pattern is read from the servo frame by a magnetic head, with respect to the synchronization timing position. | 07-18-2013 |
| 20130242427 | Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads - A thin film magnetic recording head is fabricated by forming a substrate from opposing ferrite blocks which have a ceramic member bonded between them. This structure is then diced to form a plurality of columns, wherein each column has a ferrite/ceramic combination. Each column represents a single channel in the completed head. A block of ceramic is then cut to match the columned structure and the two are bonded together. The bonded structure is then cut or ground until a head is formed, having ceramic disposed between each channel. A ferrite back-gap is then added to each channel, minimizing the reluctance of the flux path. The thin film is patterned on the head to optimize various channel configurations. | 09-19-2013 |
| 20130250447 | DETERMINING INTER-TRACK COHERENCE USING OUTPUT SIGNALS FROM FIRST AND SECOND TRACKS - An assembly and method to determine adjacent track coherence is disclosed. The assembly includes coherence circuitry configured to receive phase and frequency offsets from timing recovery circuitry and determine an inter-track phase and frequency coherence between the encoded data on a first track and the encoded data on a second track adjacent to the first track utilizing the frequency and phase offsets from the timing recovery circuitry for the output signals corresponding to the first and second tracks. | 09-26-2013 |
| 20130258515 | MOTOR DRIVE DEVICE, MAGNETIC DISK STORAGE DEVICE, AND ELECTRONIC APPLIANCE - A motor drive device has a driver circuit generating an output current for a motor and a control circuit controlling the drive circuit. The control circuit, when switching the driver circuit from a PWM-driving state to a linear-driving state, controls the timing of the switching such that the path of the output current does not change between before and after the switching, and in addition, in the middle of the switching, switches the driver circuit to a high-output-impedance state momentarily. | 10-03-2013 |
| 20130329313 | Servo Zone Detector - The present inventions are related to systems and methods for transferring information to and from a storage medium, and more particularly to systems and methods for positioning a sensor in relation to a storage medium. For example, an apparatus for determining a sensor position is disclosed that includes discrete Fourier transform calculators operable to process input data to yield a magnitude response of the input data at each of a number of candidate frequencies, a comparator operable to compare the magnitude responses to yield a winning candidate frequency, a servo controller operable to process at least one servo field in the input data to identify a position of a sensor based on the at least one servo field, and a servo frequency synthesizer operable to establish a frequency of operation in the servo controller based at least in part on the winning candidate frequency. | 12-12-2013 |
| 20140036382 | ROBUST METRIC COMPUTATION OF LONGITUDINAL POSITION (LPOS) DATA SYMBOL DETECTION - An apparatus according to one embodiment includes a digital correlator configured to compute a correlation signal between a sequence of samples of a readback servo signal and a reference waveform. A timing reference module is configured to provide a reference timing model comprising one or more interpolation instants to the digital correlator, wherein the correlation signal determined at each interpolation instant yields a detection metric for one data symbol. A correlation interpolator is configured to interpolate the correlation signal at the interpolation instants and compute a longitudinal position (LPOS) detection metric according to the interpolated correlation signal samples. | 02-06-2014 |
| 20140049853 | OFFSET-INDUCED SIGNAL CANCELLATION IN AN INTERLEAVED SAMPLING SYSTEM - Described embodiments provide an interleaved sampler having N sample and hold circuits for sampling an input signal, and M multiplexers. Each multiplexer is adapted to couple all N of the plurality of sample and hold circuits to a respective output of the interleaved sampler. The interleaved sampler samples at a sample rate of f | 02-20-2014 |
| 20140104719 | DATA RECOVERY USING NO SYNC MARK RETRY - A read channel is configured to receive at least part of a data fragment read from a storage media into a register, wherein the data fragment is configured to be formatted with a preamble, a sync mark (e.g., a syncMark), and user data, and wherein the data fragment is missing a sync mark. A position in the data fragment is selected, a sync mark is assumed at the selected position. The data is then processed assuming the sync mark is at the selected position of the data fragment to determine whether the data converges. When a determination is made that the data converges, the data is recovered. | 04-17-2014 |
| 20140139942 | MAGNETIC RECORDING DISK DRIVE WITH METHOD FOR RECOVERY OF DATA FROM FAILED DATA SECTORS - A magnetic recording disk drive determines the locations of defective bits in a failed data sector, and allows for the error correction code (ECC) to correctly decode the data from the sector. After a sector has failed decoding, the digitized waveform and the read channel state from the failed sector are stored in memory. A nondata pattern is written to the failed sector and read back to determine the locations of the defective data bits in the failed sector, which are then used to update the read channel state. The data pattern from the failed sector, with the identified bit error locations, is attempted to be decoded. If the decoding is successful then the sector is marked as bad and the correctly decoded data pattern is written to a different region of the disk, for example physical sectors specifically intended for use as spare sectors. | 05-22-2014 |
| 20140177086 | Disk Drive with Servo System with Timing Adjustments to Master Timer for SAM Detection Errors - A disk drive is described with a single servo master timer that is used to control timing critical signals such as servo gate, SAM windows, channel power save, PREAMP power save and so on. The master timer is adjusted to compensate for SAM detection errors (early, late or missed) and provides improved servo timing quality. In an embodiment the adjustable master timer can be selectably clocked by either the DLC/DSW clock or the system clock. | 06-26-2014 |
| 20140185159 | SYNC MARK DETECTION USING BRANCH METRICS FROM DATA DETECTOR - Methods and apparatus are provided for detecting a sync mark in a storage system, such as a hard disk drive. A sync mark is detected in a storage system by obtaining one or more branch metrics from a data detector in the storage system; generating one or more sync mark metrics using the one or more branch metrics from the data detector; and identifying the sync mark based on the sync mark metrics. An input data set is optionally compared with a plurality of portions of a sync mark pattern to yield corresponding comparison values and the comparison values can be summed to obtain at least one result. A sync mark found signal is asserted based upon the at least one result. | 07-03-2014 |
| 20140268400 | Systems and Methods for Loop Feedback - The present inventions are related to systems and methods for data processing, and more particularly to systems and methods for performing loop feedback in a data processing system. | 09-18-2014 |
| 20140313609 | DATA WRITING METHOD AND PROGRAM FOR TAPE DRIVE - One embodiment includes a method for writing data to a tape in a tape drive while data successively accumulated in the buffer of a file system is transferred to the tape drive. The method includes detecting a wrap turn when data is being written to the tape; allocating buffer space including a storage capacity exceeding the amount of data to be stored in the buffer during the wrap turn; successively accumulating write data in the buffer space instead of the buffer during the wrap turn; resuming the accumulation of write data in the buffer after the wrap turn has been completed; and releasing the buffer space after the write data accumulated in the buffer space has been transferred to the tape drive. | 10-23-2014 |
| 20140320995 | IMPLEMENTING DATA FREQUENCY AND DATA BITS PER SECTOR (BPS) CALIBRATION FOR NON-CIRCULAR DISK TRACKS - A method, apparatus and a data storage device are provided for implementing data frequency and data bits per sector (BPS) calibration for data written on a recordable surface including non-circular disk tracks of a storage device. A sector based BPS profile is created for data sectors on the recordable surface. The sector based BPS profile is used for modifying a number of data clock cycles based upon longer or shorter data sectors; and data clock frequency is dynamically adjusted based upon velocity jitter. | 10-30-2014 |
| 20140340780 | Method and System for Sliding-Window Based Phase, Gain, Frequency and DC Offset Estimation for Servo Channel - Sliding-window based data processing includes receiving an analog signal, converting the analog signal to a series of digital samples synchronous to a sampling clock, performing a first discrete Fourier transform on a first portion of the series of digital samples, performing a second discrete Fourier transform on a second portion of the series of digital samples, performing a third discrete Fourier transform on a third portion of the series of digital samples, generating a first series of zero phase start values by calculating a zero phase start value based on the first discrete Fourier transform in a sliding-window at a series of time increments across the servo preamble, storing the zero phase start values, and averaging the stored zero phase start values at the end of the servo preamble. | 11-20-2014 |
| 20140362463 | Timing Error Detector with Diversity Loop Detector Decision Feedback - Aspects of the disclosure pertain to an apparatus for detecting timing errors including an analog to digital converter circuit, a diversity loop detector and a timing error calculation circuit. The analog to digital converter circuit is operable to convert an input signal into a series of digital samples. The diversity loop detector is operable to apply a data detection algorithm to a plurality of signals derived from the series of digital samples at different phase offsets, to select one of the phase offsets, and to yield a detected output with the selected phase offset. The timing error calculation circuit is operable to calculate a timing error of the analog to digital converter circuit based at least in part on the selected phase offset. | 12-11-2014 |
| 20150022917 | ADAPTING TRANSFER RATE OF CACHED DATA TO PREVENT STOPPAGE OF DATA TRANSMISSION - A file system to controls access to a tape library that selectively loads and unloads a plurality of cartridges from a plurality of slots to a drive for transmitting to the file system archived data retrieved from a particular cartridge. The file system includes a cache and receives a request from a requestor to access the tape library, estimates a first data transfer rate from an anticipated tape library operation completion duration and from a capacity of cached data to be transmitted from the cache to the requestor, initiates access to the tape library, and adapts the first data transfer rate to a second data transfer rate to transmit the capacity of the cached data to the requestor throughout the anticipated tape library operation completion duration. | 01-22-2015 |
| 20150062742 | QUASI-STATICALLY TILTED HEAD HAVING DILATED TRANSDUCER PITCH - A method according to one embodiment includes reading and/or writing data to a magnetic medium using a head having an array of transducers. An axis of the array is defined between opposite ends thereof, and is tilted at an angle greater than 0° from a line oriented perpendicular to an intended direction of tape travel thereacross during the reading and/or writing. The method further includes at least one of: introducing, by a controller, a timing offset to at least one servo channel to compensate for offset in servo readback signals introduced by the tilt of the head, introducing, by the controller, a timing offset to at least some read channels to compensate for offset in readback signals introduced by a tilt of the head, and introducing, by the controller, a timing offset to at least some write channels to enable writing of transitions that are readable by a non-tilted head. | 03-05-2015 |
| 20150077878 | DATA WRITING METHOD AND PROGRAM FOR TAPE DRIVE - One embodiment includes a method. The method includes sending data from a buffer to a tape drive, and allocating buffer space when a wrap turn is anticipated. The write data is accumulated in the buffer space during the wrap turn. The buffer space is released after the write data accumulated in the buffer space has been transferred to the tape drive. | 03-19-2015 |
| 20150109698 | ITERATIVE DATA STORAGE READ CHANNEL ARCHITECTURE HAVING DROPOUT MITIGATION - According to one embodiment, a computer program product for dropout detection in a read channel includes a computer readable storage medium having program code embodied therewith, the embedded program code being readable and/or executable by a processor to execute dropout detection on a block of signal samples to detect one or more dropout events employing a set of decisions provided by a detector executing a detection algorithm, determine an approximate location for each of the one or more detected dropout events, statistically characterize the one or more detected dropout events to calculate one or more dropout profiles, and selectively filter the block of signal samples during a duration of each of the detected dropout events. Other computer program products, systems, and methods for detecting dropouts are presented in more embodiments. | 04-23-2015 |
| 20150293715 | MAGNETIC DISC DRIVE AND METHOD OF RECOVERING RECORDED DATA - According to one embodiment, a magnetic disk drive includes a read/write channel configured to process a read/write signal with respect to a magnetic disk, a data refresh module configured to perform a rewrite for refreshing recorded data on the magnetic disk, a data capture module configured to capture read data in the read/write channel, a timing determination module configured to determine power shutdown timing during the rewriting from the read data, and a data recovery module configured to recover the read data by dividing the read data into two items based on the power shutdown timing, shifting timing of one item of the read data, and combining the shifted data with the other item of the read data. | 10-15-2015 |
| 20150310880 | MAGNETIC RECORDING HEAD, MAGNETIC HEAD ASSEMBLY, MAGNETIC RECORDING APPARATUS, AND MAGNETIC RECORDING METHOD - An example magnetic recording apparatus includes a magnetic recording medium, a magnetic recording head and a signal processor. The magnetic recording head includes a first magnetic pole to apply a recording magnetic field to the magnetic recording medium; a spin torque oscillator arranged parallel to the first magnetic pole; and a first coil to magnetize the first magnetic pole. The signal processor writes and reads a signal on the magnetic recording medium by using the magnetic recording head and includes a first current circuit to supply a recording current to the first coil, the recording current including a recording signal to be recorded on the magnetic recording medium. The recording current includes either one of a signal changing at a frequency higher than that of the recording signal, and a signal having the same frequency as the recording signal and changing an absolute value thereof in one cycle. | 10-29-2015 |
| 20160111119 | INTEGRATED SERVO FIELD FOR MEMORY DEVICE - A pattern of features of a storage medium includes first features having a first logical state and second features having a second logical state, wherein a cross track dimension of the first features is different from a cross track dimension of the second features. A transducer of a memory device senses the pattern of features and generates a transducer signal. Read circuitry samples the transducer signal at a frequency of a sampling clock signal and generates a read signal from the sampled transducer signal. Servo electronics includes a demodulator that demodulates at least first and second orthogonal frequency components of the read signal. Timing circuitry synchronizes a phase of the sampling clock signal with a phase of the pattern of features using the first orthogonal frequency component. Position error circuitry generates a signal indicating a cross track positional offset of the transducer relative to the features using the first and second orthogonal frequency components. | 04-21-2016 |
| 360052000 | With incremental movement between record and head | 3 |
| 20110013307 | METHOD AND APPARATUS TO IDENTIFY A DATA BAND ENCODED BETWEEN TWO SERVO BANDS IN A SEQUENTIAL INFORMATION STORAGE MEDIUM - A method and apparatus is presented to determine a lateral position of a read/write head relative to a sequential information storage medium having a servo signal encoded therein and moving adjacent to the read/write head, where the servo signal comprises a plurality of pulses. The method includes detecting the servo signal using the read/write head and calculating a timing interval between each of the pulses using a clock rate of a clock signal. The clock rate is then adjusted based upon the velocity of the sequential information storage medium. | 01-20-2011 |
| 20140362464 | POSITION DETECTION ENCODER - A position detection encoder includes a scale and a detection head and has position detection circuits which are capable of outputting respective pieces of position information on X | 12-11-2014 |
| 20150043101 | HIGH DENSITY TIMING BASED SERVO FORMAT FOR USE WITH TILTED TRANSDUCER ARRAYS - A product, according to one embodiment, includes a magnetic recording tape having opposite ends, a longitudinal axis of the magnetic recording tape being defined between the ends. The magnetic recording tape has at least one servo track, the at least one servo track having a plurality of first magnetic bars and a plurality of third magnetic bars oriented to form chevron-like patterns with the first magnetic bars. The first magnetic bars each have a longitudinal axis oriented at a first angle between 2 and 88 degrees from the longitudinal axis of the magnetic recording tape. The third magnetic bars each have a longitudinal axis oriented at a second angle between 2 and 88 degrees from the longitudinal axis of the magnetic recording tape, the second angle having a different numerical absolute value than the first angle. | 02-12-2015 |
