Patents by Inventor Roger W. Wood

Roger W. Wood 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: 10283146
    Abstract: According to one embodiment, a system includes a head, where the head includes: an optical signal source configured to emit a first optical signal, and a near-field transducer (NFT) configured to focus the first optical signal on a moving ferroelectric storage medium positioned below the head. The system also includes a detector operatively coupled to the head, where the detector is configured to detect a second optical signal generated in and reflected from the ferroelectric storage medium, and where the second optical signal has twice the optical frequency as the first optical signal.
    Type: Grant
    Filed: April 3, 2018
    Date of Patent: May 7, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Takuya Matsumoto, Barry C. Stipe, Ikuya Tagawa, Roger W. Wood
  • Publication number: 20180350397
    Abstract: According to one embodiment, a system includes a head, where the head includes: an optical signal source configured to emit a first optical signal, and a near-field transducer (NFT) configured to focus the first optical signal on a moving ferroelectric storage medium positioned below the head. The system also includes a detector operatively coupled to the head, where the detector is configured to detect a second optical signal generated in and reflected from the ferroelectric storage medium, and where the second optical signal has twice the optical frequency as the first optical signal.
    Type: Application
    Filed: April 3, 2018
    Publication date: December 6, 2018
    Inventors: Takuya Matsumoto, Barry C. Stipe, Ikuya Tagawa, Roger W. Wood
  • Patent number: 9632863
    Abstract: In general, techniques are described for performing track-error-correcting code on data. A hard drive comprising a storage device and a read channel may be configured to perform the techniques. The read channel may be configured to read data from a track comprising a plurality of data sectors each comprising a plurality of bits, and a parity sector comprising a plurality of parity bits, wherein the data includes a plurality of bit groups, each bit group including a single bit from each data sector, and wherein each parity bit corresponds to a respective bit group, perform a track parity check, and, responsive to determining that the data includes an error, identify one or more data sectors as possible sources of the at least one error and adjust a log-likelihood ratio for at least one bit from the bit group.
    Type: Grant
    Filed: January 13, 2015
    Date of Patent: April 25, 2017
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Richard L. Galbraith, Weldon M. Hanson, Roger W. Wood
  • Publication number: 20160203041
    Abstract: In general, techniques are described for performing track-error-correcting code on data. A hard drive comprising a storage device and a read channel may be configured to perform the techniques. The read channel may be configured to read data from a track comprising a plurality of data sectors each comprising a plurality of bits, and a parity sector comprising a plurality of parity bits, wherein the data includes a plurality of bit groups, each bit group including a single bit from each data sector, and wherein each parity bit corresponds to a respective bit group, perform a track parity check, and, responsive to determining that the data includes an error, identify one or more data sectors as possible sources of the at least one error and adjust a log-likelihood ratio for at least one bit from the bit group.
    Type: Application
    Filed: January 13, 2015
    Publication date: July 14, 2016
    Inventors: Richard L. Galbraith, Weldon M. Hanson, Roger W. Wood
  • Patent number: 8792210
    Abstract: In one embodiment, a system includes a writer for shingled recording which includes a write pole having a trailing edge and first and second side edges extending from the trailing edge. The writer further includes a shield extending along and about parallel to at least an entire length of the trailing edge, the shield also extending along at least a portion of the first side edge. Other systems are also presented which include advanced shingled writing head designs.
    Type: Grant
    Filed: September 12, 2012
    Date of Patent: July 29, 2014
    Assignee: HGST Netherlands B.V.
    Inventors: Anton R. de la Fuente, Masafumi Mochizuki, James T. Olson, Roger W. Wood
  • Publication number: 20130016443
    Abstract: In one embodiment, a system includes a writer for shingled recording which includes a write pole having a trailing edge and first and second side edges extending from the trailing edge. The writer further includes a shield extending along and about parallel to at least an entire length of the trailing edge, the shield also extending along at least a portion of the first side edge. Other systems are also presented which include advanced shingled writing head designs.
    Type: Application
    Filed: September 12, 2012
    Publication date: January 17, 2013
    Applicant: HGST NETHERLANDS B.V.
    Inventors: Anton R. de la Fuente, Masafumi Mochizuki, James T. Olson, Roger W. Wood
  • Patent number: 8310786
    Abstract: In one embodiment, a system includes a writer for shingled recording which includes a write pole having a trailing edge and first and second side edges extending from the trailing edge. The writer further includes a shield extending along and about parallel to only a portion of the trailing edge or only a portion of the first side edge, and the shield does not extend along the second side edge. In addition, an angle formed between the first side edge and the trailing edge along an air bearing surface side of the writer is different than an angle formed between the second side edge and the trailing edge along the air bearing surface side of the writer. Other systems are also presented which include advanced shingled writing head designs.
    Type: Grant
    Filed: September 9, 2009
    Date of Patent: November 13, 2012
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Anton R. de la Fuente, Masafumi Mochizuki, James T. Olson, Roger W. Wood
  • Publication number: 20110058277
    Abstract: In one embodiment, a system includes a writer for shingled recording which includes a write pole having a trailing edge and first and second side edges extending from the trailing edge. The writer further includes a shield extending along and about parallel to only a portion of the trailing edge or only a portion of the first side edge, and the shield does not extend along the second side edge. In addition, an angle formed between the first side edge and the trailing edge along an air bearing surface side of the writer is different than an angle formed between the second side edge and the trailing edge along the air bearing surface side of the writer. Other systems are also presented which include advanced shingled writing head designs.
    Type: Application
    Filed: September 9, 2009
    Publication date: March 10, 2011
    Inventors: Anton R. de la Fuente, Masafumi Mochizuki, James T. Olson, Roger W. Wood
  • Patent number: 5535187
    Abstract: A system for encoding and decoding binary data in a data transmission system, such as a magnetic or optical data storage channel. The encoding process is implemented as a two-step RLL coding procedure wherein the original user bit data are first encoded as an asymmetric RLL code signal at a reduced clock rate and then translated to a second even-spaced RLL code signal suitable for recording to a data storage medium at a full-speed clock rate. The system also provides for recovering suitable even-spaced RLL codes recorded at a full-speed clock rate, translating the recovered even-spaced RLL code signal to an asymmetric RLL code signal at a reduced clock rate, and then decoding the asymmetric RLL code signal to recover the original user bit data. A preferred embodiment uses a rate 2/5 (2, 16, 2) even-spaced RLL code at a full-speed clock rate and a rate 4/5 (0,7; 1,8) asymmetric RLL code at a half-speed clock rate.
    Type: Grant
    Filed: December 15, 1993
    Date of Patent: July 9, 1996
    Assignee: Intenational Business Machines Corporation
    Inventors: Constantin M. Melas, Daniel Rugar, Pantas Sutardja, Roger W. Wood
  • Patent number: 5448571
    Abstract: A synchronization pattern is provided within an incoming waveform which represents a serial data stream transmitted at a rate determined by a data clock. The synchronization pattern includes a periodic training portion and a sync word portion. The periodic training portion is periodic and has a preselected period. As the periodic training portion is received, a receiver clock phase-locks to the periodic training portion of the incoming waveform, and a sampling circuit periodically samples the incoming waveform relative to the phase and frequency of the receiver clock to produce sample words. Thereafter, a subset of the sample words are selected utilizing a selection pattern having a period equal to the period of the periodic training portion of the incoming waveform. Utilizing the selected subset of sample words, a sync indicator word is produced and compared to preselected criteria. Such a sync indicator word may be produced with reference to the sign of each sample word of the subset of sample words.
    Type: Grant
    Filed: April 26, 1994
    Date of Patent: September 5, 1995
    Assignee: International Business Machines Corporation
    Inventors: Ju-Hi J. Hong, Roger W. Wood
  • Patent number: 5357520
    Abstract: A method and apparatus are provided for determining an adjustable precompensation value in a partial-response maximum-likelihood (PRML) data channel. The PRML data channel includes an adjustable precompensation function for modulating the write data waveform. A predetermined test pattern is written using write circuitry in the disk file. The predetermined test pattern is insensitive to channel misequalization and provides a reference for gain and timing control. The written predetermined test pattern is read back using read circuitry in the disk file. An error in sample values in the read back predetermined test pattern is identified using logic provided in the PRML data channel while performing a standard read operation of a data sector written with the test pattern. The adjustable write precompensation value is adjusted responsive to identifying an error.
    Type: Grant
    Filed: January 31, 1992
    Date of Patent: October 18, 1994
    Assignee: International Business Machines Corporation
    Inventors: Patrick C. Arnett, Jonathan D. Coker, Richard L. Galbraith, Yaw-Shing Tang, Roger W. Wood
  • Patent number: 5280489
    Abstract: A method and apparatus for detecting spectral null sequences of a spectrally-constrained code on a noisy communications channel. From a Viterbi detector with a trellis structure comprising a plurality of states and edges, predetermined ones of the states and edges in the trellis structure are deleted at preselected times modulo N, such as times .phi. modulo N and/or at intermediate times m modulo N, where m=.phi., thereby to create a time-varying trellis structure for limiting the maximum length of dominant error events. The deleted edges are generally those edges which would have entered or emanated from the deleted states if they were not deleted. The trellis structure may be a so-called systolic structure, in which case the spectral null sequences are preferably DC-free or Nyquist free.
    Type: Grant
    Filed: April 15, 1992
    Date of Patent: January 18, 1994
    Assignee: International Business Machines Corporation
    Inventors: Lyle J. Fredrickson, Razmik Karabed, James W. Rae, Paul H. Siegel, Hemant K. Thapar, Roger W. Wood
  • Patent number: 5041922
    Abstract: Magnetic record media are described that have an overlying or underlying magnetically saturable high permeability keeper layer in addition to a high coervicity magnetic layer in which magnetic signals are stored. These media are used in magnetic signal processing devices whose transducers are capable of generating a keeper layer-saturating bias flux. In signal reproduction the bias flux magnetically forms a saturation zone in the nature of virtual gap in the keeper layer that directs signal flux between the media and the transducer.
    Type: Grant
    Filed: July 23, 1990
    Date of Patent: August 20, 1991
    Assignee: Ampex Corporation
    Inventors: Roger W. Wood, Beverley R. Gooch, Rex Niedermeyer
  • Patent number: 4555784
    Abstract: A parity and/or syndrome generator generates a block parity check for the detection and/or correction of errors in a multi-channel digital data communication system using a linear code or a coset of such code in which data and parity bytes are intended to be digitally encoded in n by m bit data blocks to form a respective codeword in n parallel bytes of m bits in serial order of significance in the form of a codeword having n elements represented by respective bytes in the Galois field GF(2.sup.m), such Galois field being defined by an m-order field generator polynomial in integral powers of z between z.sup.0 and z.sup.m, where z is the inverse of the delay operator z.sup.-1 of such Galois field. A first circuit produces a first partial parity check for the bit of such significance in each of the n elements of the respective codeword. A second circuit sums in the Galois field over all elements of the codeword the first partial parity checks to form a second partial parity check.
    Type: Grant
    Filed: March 5, 1984
    Date of Patent: November 26, 1985
    Assignee: Ampex Corporation
    Inventor: Roger W. Wood
  • Patent number: 4527269
    Abstract: An encoder verifier checks the functioning of a Reed-Solomon encoder in which data and parity bytes are intended to be digitally encoded in data blocks to form for each data block a respective codeword in multi-bit bytes in the form of a Galois field polynomial that is divisible in the Galois field by a generator polynomial, such generator polynomial being the Galois field product of a plurality of factors. A Galois field polynomial divider divides respective codewords by one of the factors to produce a remainder signal systematically related to the remainder from such division. An indicator responsive to the remainder signal produces an indication of encoder malfunction when the remainder signal corresponds to a remainder other than zero.
    Type: Grant
    Filed: February 8, 1983
    Date of Patent: July 2, 1985
    Assignee: Ampex Corporation
    Inventors: Roger W. Wood, Charles L. Matson