Patents by Inventor Guoxiao Guo

Guoxiao Guo has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8970982
    Abstract: A disk drive is disclosed comprising a disk comprising a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors. A position of the head is measured based on the servo sectors, and a compensated position of the head is generated based on the measured position of the head and a fly height of the head. The head is actuated over the disk based on the compensated position of the head.
    Type: Grant
    Filed: December 9, 2013
    Date of Patent: March 3, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jianguo Zhou, Abhishek Dhanda, Eugene C. Wu, Teddy T. Chen, Sanghoon Chu, Guoxiao Guo, Jie Yu
  • Patent number: 8970980
    Abstract: A disk drive is disclosed comprising a disk and a head actuated over the disk. A burst metric is generated in response to a burst read signal. The burst metric comprises at least one of an alpha metric comprising a ratio of a first burst amplitude of a first phased based servo burst measured at a first radial offset to a second burst amplitude of a second phased based servo burst measured at a second radial offset, a harmonic metric comprising a ratio of a first harmonic of the burst read signal as the head is moved radially over the disk to a higher harmonic of the burst read signal as the head is moved radially over the disk, and a spiral track crossing metric comprising a first and second interval each representing a partial duration of the read element crossing a spiral track.
    Type: Grant
    Filed: June 27, 2011
    Date of Patent: March 3, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Abhishek Dhanda, Wei Guo, Russ A. Quisenberry, Guoxiao Guo, Jie Yu
  • Patent number: 8970979
    Abstract: A disk drive is disclosed comprising a servo control system configured to control an actuator for actuating a head over a disk. Servo sectors are sampled at a servo sample frequency fs to generate a position error signal PES(k) that is filtered with a compensator to generate a first control signal u1(k). A first discrete-time sinusoid comprising a sinusoid frequency of fs+?f is added to the first control signal u1(k) to generate a second control signal u2(k). The second control signal u2(k) is applied to the actuator, and a frequency response of the actuator is determined at the frequency |?f|. The frequency response of the actuator is determined at the frequency fs+?f based at least in part on the frequency response of the actuator at the frequency |?f| and a measured signal of the servo control system when applying the second control signal u2(k) to the actuator.
    Type: Grant
    Filed: December 18, 2013
    Date of Patent: March 3, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Qing Wei Jia, Hui Li, Shuyu Cao, Guoxiao Guo, Jie Yu
  • Patent number: 8941945
    Abstract: A data storage device is disclosed comprising a first disk surface comprising servo tracks defined by servo sectors and recorded at a first radial density, and a first head actuated over the first disk surface. A servo sector on the first disk surface is read to generate a first physical position measurement that is converted into a first virtual position measurement corresponding to a nominal radial density of servo tracks different from the first radial density. The first head is servoed over the first disk surface based on the first virtual position measurement.
    Type: Grant
    Filed: June 6, 2014
    Date of Patent: January 27, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Michael Chang, Wei Guo, Yun Hong, Brian P. Rigney, Guoxiao Guo
  • Patent number: 8934186
    Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones, and at least one servo sector of a servo track comprises a partial track address. A read signal generated by the head is processed to detect a current servo zone for the head, and the read signal is processed to detect the partial track address in one of the servo sectors of the current servo zone. A full track address is generated based on the detected servo zone and the detected partial track address.
    Type: Grant
    Filed: April 17, 2014
    Date of Patent: January 13, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Wei Guo, Michael Chang, Russ A. Quisenberry, Richard K. Wong, Guoxiao Guo
  • Patent number: 8922938
    Abstract: A disk drive is disclosed comprising a servo control system operable to actuate a head over a disk. A disturbance signal is generated in response to a vibration, and the disturbance signal is filtered with a first filter comprising a frequency response to generate a filtered disturbance signal. The filtered disturbance signal is filtered with a model of the servo control system to generate a compensated disturbance signal. An error signal of the servo control system is filtered with a second filter comprising the frequency response to generate a filtered error signal. An adaptation control signal is generated in response to the compensated disturbance signal and the filtered error signal, and an adaptive filter is adapted in response to the adaptation control signal, wherein the adaptive filter filters the disturbance signal to generate feed-forward compensation values applied to the servo control system to compensate for the vibration.
    Type: Grant
    Filed: November 2, 2012
    Date of Patent: December 30, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Xu Chen, Jianguo Zhou, Wei Xi, Kuang-Yang Tu, Guoxiao Guo
  • Patent number: 8917469
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks defined by a plurality of servo sectors. An estimated track ID is generated and a plurality of proximate track IDs is generated having values proximate the estimated track ID. A set of Gray codes is generated each corresponding to the estimated track ID and the proximate track IDs, wherein each Gray code in the set of Gray codes comprises N bits, and M bits out of a high order of the N bits comprise the same value. A recorded Gray code is detected in a first servo sector to generate a detected Gray code, and an error in the detected Gray code is corrected by inverting at least one bit in the detected Gray code comprising a value that is different from the value of the corresponding bit in the M bits.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: December 23, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Donald Brunnett, Jianguo Zhou, Wai Ee Wong
  • Patent number: 8824081
    Abstract: A disk drive is disclosed comprising a disk comprising a plurality of data tracks defined by servo sectors. Each servo sector comprises a periodic preamble recorded at a first frequency, servo data, a periodic reference pattern recorded at a second frequency different from the first frequency, and at least one servo burst. A servo sector is processed by processing the periodic preamble to extract the servo data, demodulating the servo burst in response to the periodic reference pattern, generating a position error signal based on the extracted servo data and the demodulated servo burst, and measuring a fly height of the head based on the periodic reference pattern.
    Type: Grant
    Filed: March 13, 2012
    Date of Patent: September 2, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Jie Yu
  • Patent number: 8792202
    Abstract: A disk drive is disclosed comprising a head and a disk comprising a plurality of servo tracks, wherein each servo track comprises a plurality of servo sectors. The disk drive further comprises control circuitry comprising a servo control system operable to actuate the head over the disk in response to the servo sectors. The disk is rotated at a first speed and the servo sectors are read at a first servo sample frequency to generate first servo samples. The disk is rotated at a second speed different from the first speed and the servo sectors are read at a second servo sample frequency to generate second servo samples. The second servo samples are processed to measure a frequency response of the servo control system proximate the first servo sample frequency.
    Type: Grant
    Filed: August 29, 2013
    Date of Patent: July 29, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jie Wan, Xiaotian Xu, Shuyu Cao, Jern Khang Tan, Guoxiao Guo, Wei Xi
  • Patent number: 8780477
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks, wherein the servo tracks form a plurality of servo zones, and a servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone. A disk locked clock is synchronized to the data rate of the servo sectors in the first servo zone, wherein the disk locked clock for generating a timing window relative to the servo sectors. When the head crosses from the first servo zone to the second servo zone, at least one of the disk locked clock and the timing window is adjusted to compensate for a timing transient.
    Type: Grant
    Filed: June 21, 2012
    Date of Patent: July 15, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Wei Guo, Michael Chang, Guoxiao Guo, Jie Yu
  • Patent number: 8724245
    Abstract: A disk drive is disclosed comprising a head actuated over a disk, the disk comprising a plurality of servo sectors defining a plurality of servo tracks, wherein the servo tracks form a plurality of servo zones. A servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone. A boundary of a first servo zone overlaps with a boundary of a second servo zone over a transition zone. The servo sectors of the first servo zone are interleaved with the servo sectors of the second servo zone within the transition zone. At least one servo parameter is adjusted when the head is over the transition zone in order to transition between the first servo zone and the second servo zone.
    Type: Grant
    Filed: June 21, 2012
    Date of Patent: May 13, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Steven C. Smith, Charles A. Park, Siri S. Weerasooriya, Jenghung Chen, Guoxiao Guo, Wei Guo
  • Patent number: 8717704
    Abstract: A disk drive is disclosed comprising a disk having a plurality of servo tracks defined by servo sectors, and a head actuated over the disk. The disk drive further comprises control circuitry comprising a servo control system operable to position the head over the disk. A disturbance is induced in the servo control system, and while positioning the head over the disk, a data track is accessed. The disturbance induced in the servo control system causes the data track to be non-circular relative to a rotation axis of the disk such that the non-circular data track crosses multiple of the servo tracks over a revolution of the disk.
    Type: Grant
    Filed: February 28, 2012
    Date of Patent: May 6, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jie Yu, Guoxiao Guo, Jianguo Zhou, Sanghoon Chu, Young-Hoon Kim, Abhishek Dhanda
  • Patent number: 8711506
    Abstract: A disk drive is disclosed comprising a disk comprising a plurality of servo tracks defined by servo sectors. The disk drive further comprises a head comprising a read element offset linearly from a write element by a gap such that when the disk rotates, the read element reaches a servo sector before the write element. During a first operation, a first length of a beginning of the servo sector is read, and during a write operation, a second length of the beginning of the servo sector shorter than the first length is read to enable data to be written while the read element is over at least part of the servo sector.
    Type: Grant
    Filed: May 31, 2012
    Date of Patent: April 29, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Davide Giovenzana, John W. Vanlaanen, Prakash Balasubramaniam, Teik Ee Yeo, Guoxiao Guo, Honge Wang, Jie Yu, Philip S. Gordon
  • Patent number: 8693123
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of tracks defined by a plurality of servo sectors. An estimated track ID is generated representing an estimated radial location of the head. A high order Gray code in a first servo sector is detected, and errors in the high order Gray code are corrected using the estimated track ID to generate a corrected Gray code. The corrected Gray code is decoded into a first part of a detected track ID. A low order track code is detected in the first servo sector, and the low order track code is decoded into a second part of the detected track ID. The first part of the detected track ID is combined with the second part of the detected track ID.
    Type: Grant
    Filed: June 27, 2011
    Date of Patent: April 8, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Jie Yu, Abhishek Dhanda
  • Patent number: 8654467
    Abstract: A disk drive is disclosed comprising a disk including a plurality of servo tracks defined by servo sectors, wherein each servo sector comprises a servo preamble. A head is actuated over the disk, wherein the head is operable to generate a read signal. The disk drive further comprises control circuitry including an analog cutoff filter operable to filter the read signal to generate a filtered read signal. The filtered read signal is sampled to generate read samples. During a normal operating mode, the analog cutoff filter is configured to have a first bandwidth. During a measurement mode, the analog cutoff filter is configured to have a second bandwidth greater than the first bandwidth, and the read samples representing at least part of the servo preamble are processed to measure a signal-to-noise ratio (SNR) and/or a fly height of the head.
    Type: Grant
    Filed: April 16, 2012
    Date of Patent: February 18, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Wai Ee Wong, Xiaotian Xu, Jinchuan Zheng, Guoxiao Guo, Jie Yu
  • Patent number: 8619385
    Abstract: A disk drive is disclosed comprising a disk including a plurality of sectors each comprising a sector sync mark pattern and sector data preceding and following the sector sync mark pattern, and a head actuated over the disk for generating a read signal. A data sequence is detected from the read signal, and the data sequence is correlated with an extended sync mark comprising a target sync mark pattern and target data. The correlation of the target sync mark pattern with the data sequence is biased relative to the correlation of the target data with the data sequence.
    Type: Grant
    Filed: January 28, 2011
    Date of Patent: December 31, 2013
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Jie Yu
  • Patent number: 8576506
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones. A disk locked clock is synchronized relative to a servo data rate of the servo zone the head is over. A first reader/writer gap is measured in cycles of the disk locked clock at a first servo track in the first servo zone. A second reader/writer gap is measured in cycles of the disk locked clock at a second servo track in the second servo zone. The first and second reader/writer gaps are normalized to generate a normalized first and second reader/writer gaps. A third reader/writer gap is estimated in cycles of the disk locked clock at a third servo track in the second servo zone based on the normalized first and second reader/writer gaps.
    Type: Grant
    Filed: June 21, 2012
    Date of Patent: November 5, 2013
    Assignee: Western Digital Technologies, Inc.
    Inventors: Honge Wang, Michael Chang, Abhishek Dhanda, Huanxiang Ruan, Guoxiao Guo
  • Patent number: 8531798
    Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors that define a plurality of servo tracks, wherein the servo sectors comprise a plurality of servo bursts. A radial velocity of the head is detected relative to the servo tracks. At least two of the servo bursts are read to generate servo burst signals, and the servo burst signals are adjusted in response to the radial velocity of the head. A position error signal is generated for the head in response to the adjusted servo burst signals.
    Type: Grant
    Filed: December 13, 2010
    Date of Patent: September 10, 2013
    Assignee: Western Digital Technologies, Inc.
    Inventors: Wei Xi, Abhishek Dhanda, Guoxiao Guo, Jie Yu
  • Patent number: 8213106
    Abstract: A disk drive includes a plurality of servo zones of different servo frequencies and a read channel. The disk drive also includes a frequency detector operable to determine a servo frequency associated with a servo sector. The read channel includes a voltage-controlled oscillator operable to provide a reference clock; frequency multiplier/divider circuitry operable to multiply or divide the reference clock from the voltage-controlled oscillator by a first factor to generate a first servo timing recovery clock for the first servo zone, the first factor selected based at least in part on the servo frequency determined by the frequency detector; and a servo demodulator operable to demodulate the at least a portion of a servo sector using the first servo timing recovery clock.
    Type: Grant
    Filed: March 10, 2009
    Date of Patent: July 3, 2012
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Jie Yu
  • Patent number: 7916416
    Abstract: A disk drive is disclosed comprising a disk having servo data defining a plurality of servo tracks. The servo data comprises a preamble comprising a varying length across a radius of the disk, and a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble. The tilt angle varies across the radius of the disk commensurate with the varying length of the preamble. A position error signal (PES) is generated in response to a phase difference when reading the preamble and the slanted line servo bursts.
    Type: Grant
    Filed: September 29, 2008
    Date of Patent: March 29, 2011
    Assignee: Western Digital Technologies, Inc.
    Inventors: Guoxiao Guo, Jie Yu