Patents by Inventor Robert Leslie Cloke

Robert Leslie Cloke 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: 6693760
    Abstract: A preamplifier circuit is disclosed comprising a data input for receiving write data, a read signal output for outputting an amplified read signal, a read signal input for receiving a read signal from a read element, and a write signal output for supplying a write signal to a write element. The preamplifier circuit further comprises a first amplifier circuit, responsive to the write data, for generating the write signal supplied to the write element, and a second amplifier circuit for amplifying the read signal from the read element to generate the amplified read signal output via the read signal output. A head control circuit, responsive to head select data, simultaneously enables the first and second amplifier circuits to perform a simultaneous read and write operation.
    Type: Grant
    Filed: March 31, 2000
    Date of Patent: February 17, 2004
    Assignee: Western Digital Technologies, Inc.
    Inventors: Mohamad T. Krounbi, John Cuda, Jack M. Chue, Robert Leslie Cloke, David Price Turner, Gary L. Dunbar
  • Patent number: 6600620
    Abstract: The present invention may be regarded as a self-servo writing disk drive comprising a head having a read element radially offset from a write element. During a first time interval, the read element is positioned over a first radial location to read first A clock data to generate first circumferential timing information and first A servo bursts to generate first position control information. The first position control information is used for positioning the write element over a second radial location, and the first circumferential timing information is used for writing second B clock data and second B servo bursts to the second radial location. During a second time interval, the read element is positioned over the first radial location to read first B clock data to generate second circumferential timing information and first B servo bursts to generate second position control information.
    Type: Grant
    Filed: March 31, 2000
    Date of Patent: July 29, 2003
    Assignee: Western Digital Technologies, Inc.
    Inventors: Mohamad T. Krounbi, John Cuda, Jack M. Chue, Robert Leslie Cloke, David Price Turner, Gary L. Dunbar
  • Patent number: 6441981
    Abstract: A disk drive includes a disk having a disk surface, the disk surface having a plurality of tracks arranged in an embedded servo format. The disk surface includes a plurality of radially-extending user-data regions and a plurality of radially-extending servo-data regions. Each user-data region has a plurality of data zones in each of which user data are stored in a plurality of track segments at a data channel frequency particular to that data zone. Each servo-data region has a plurality of servo zones in each of which servo data are stored in a plurality of track segments at a servo channel frequency particular to that servo zone, wherein in at least one of the tracks having servo data and user data, the servo channel frequency differs from the data channel frequency.
    Type: Grant
    Filed: May 1, 2001
    Date of Patent: August 27, 2002
    Assignee: Western Digital Technologies, Inc.
    Inventors: Robert Leslie Cloke, Richard William Hull, Vafa James Rakshani, David Price Turner
  • Patent number: 6411452
    Abstract: A hard disk drive has a pattern detector for providing fault-tolerant detection of a data sync mark represented by a substring of a concatenated string of error-prone read symbols and for providing a reduced risk that a nonmark substring of the concatenated string of error-prone read symbols will be misdetected as a sync mark. The data sync mark write string corresponds to an ordered set of m expected symbols selected to have maximum distance from all non-mark substrings of m consecutive expected symbols that exist in the concatenated string of expected symbols.
    Type: Grant
    Filed: March 11, 1997
    Date of Patent: June 25, 2002
    Assignee: Western Digital Technologies, Inc.
    Inventor: Robert Leslie Cloke
  • Patent number: 6292912
    Abstract: A disk drive has a normal mode of operation and a built-in self-test (BIST) mode of operation for producing a sequence of channel metrics {&Ggr;n}. The disk drive includes a recording surface having a plurality of bit cells and a transducer for reading the plurality of bit cells to produce a noise-corrupted read signal. The disk drive further includes means responsive to the noise-corrupted read signal for generating a sequence of observed samples {yn}, the sequence of observed samples {yn} forming a sequence of observed-sample subsequences {Yn}. An expected sample generator operates during the BIST mode of operation to provide a sequence of expected samples {wn}, the sequence of expected samples forming a sequence of expected-sample subsequences {Wn}. A channel metrics &Ggr;n computation system computes a sequence of channel metrics {&Ggr;n}.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: September 18, 2001
    Assignee: Western Digital Technologies, Inc.
    Inventors: Robert Leslie Cloke, Patrick James Lee, Howard Anthony Baumer
  • Patent number: 6262857
    Abstract: A disk drive includes a disk having a disk surface, the disk surface having a plurality of tracks arranged in an embedded servo format. The disk surface includes a plurality of radially-extending user-data regions and a plurality of radially-extending servo-data regions. Each user-data region has a plurality of data zones in each of which user data are stored in a plurality of track segments at a data channel frequency particular to that data zone. Each servo-data region has a plurality of servo zones in each of which servo data are stored in a plurality of track segments at a servo channel frequency particular to that servo zone. The servo channel frequency differs from the data channel frequency for at least one track.
    Type: Grant
    Filed: June 23, 1998
    Date of Patent: July 17, 2001
    Assignee: Western Digital Corporation
    Inventors: Richard William Hull, Vafa James Rakshani, David Price Turner, Robert Leslie Cloke
  • Patent number: 6246346
    Abstract: A storage system employs a method for encoding a sequence of input data blocks into a sequence of codewords. Each input data block includes a first predetermined number of bits (the data block length). Each codeword includes a second predetermined number of bits (the codeword length). The code rate, i.e., the ratio of the first number to the second number, is greater than ¾. The method is performed in a sampled-data channel in a storage system; and the channel includes a circuit the performance of which is adversely affected by an excessive run length of bits between occurrences of a predetermined influential pattern. Preferably, the influential pattern is a two-bit sequence of adjacent 1's, which favorably influences the performance of a timing recovery circuit. The method includes receiving the sequence of input data blocks and generating the sequence of codewords responsive to the received sequence of input data blocks.
    Type: Grant
    Filed: October 24, 1997
    Date of Patent: June 12, 2001
    Assignee: Western Digital Corporation
    Inventors: Robert Leslie Cloke, Patrick James Lee, Steven William McLaughlin
  • Patent number: 6208477
    Abstract: In a hard disk drive, a semiconductor chip includes a circuit used in a built-in self test (“BIST”) to determine an amplitude of a dibit echo for characterizing nonlinear distortion of a readback signal. Preferably, write precompensation is performed based on results of the BIST to minimize distortion attributable to intersymbol interference. A generator is used to generate a maximal length pseudo-random sequence. This maximal length pseudo-random sequence is input to a correlator which performs a correlation between the maximal length pseudo-random bit sequence and a readback signal responsive to the pseudo-random sequence that was stored onto a disk of the hard disk drive. In one embodiment, a seed value stored in memory is loaded into the generator upon detection of a synchronization signal read from the disk. With the appropriate seed value loaded into the generator, a specific pseudo-random bit sequence corresponding to a sample point of interest is then generated.
    Type: Grant
    Filed: June 6, 1997
    Date of Patent: March 27, 2001
    Assignee: Western Digital Corporation
    Inventors: Robert Leslie Cloke, Patrick James Lee
  • Patent number: 6178056
    Abstract: A disk drive includes a disk surface having a plurality of tracks arranged in an embedded servo format including servo track segments for storing servo data and data track segments for storing user data. The disk drive includes a read element operative during a user-data read operation for reading data from the disk surface to produce a time-multiplexed analog read signal that during a revolution of the disk represents analog read servo data during each of a first set of time intervals and represents analog read user data during each of a second set of time intervals. The disk drive includes a sampled signal processing circuit that generates a servo state variable while processing the time-multiplexed read signal during the first servo time interval and a user data state variable while processing the time-multiplexed read signal during the first user data time interval.
    Type: Grant
    Filed: April 15, 1999
    Date of Patent: January 23, 2001
    Assignee: Western Digital Corporation
    Inventors: Robert Leslie Cloke, Richard W. Hull, Vafa James Rakshani, David Price Turner
  • Patent number: 5822143
    Abstract: A partial-response maximum-likelihood (PRML) sequence detector with decision feedback equalization (DFE) for a disk drive read channel. The symbol recovery method for a disk drive read channel produces a sequence of samples X.sub.n of a magnetic readback signal with amplitudes representing the readback signal during corresponding sample intervals n=1-N. A DFE circuit generates a sequence of equalized samples y.sub.n and includes a feed-forward filter that removes precursor ISI from the sequence of sample signals x.sub.n to produce a sequence of feed-forward equalized samples w.sub.n, detection logic that translates the sequence of equalized samples y.sub.n into a sequence of detected symbols y.sub.n, and a feedback filter that filters the sequence of detected symbols y.sub.n to produce a sequence of equalization feedback values e.sub.n to offset postcursor ISI remaining in the sequence of feed-forward equalized samples w.sub.n. A combinational circuit receives the feed-forward equalized samples w.sub.
    Type: Grant
    Filed: June 11, 1996
    Date of Patent: October 13, 1998
    Assignee: Western Digital Corporation
    Inventors: Robert Leslie Cloke, Patrick James Lee