Patents Examined by Alan Faber
  • Patent number: 5978171
    Abstract: In a reproducing apparatus for reproducing an information signal from a recording medium on which a number of recording tracks are formed in parallel to each other and on which the information signal is recorded with a pilot signal component superimposed on the information signal periodically at intervals of a predetermined number of tracks, a pair of reproducing heads are arranged to reproduce signals by concurrently tracing mutually adjacent tracks, a switching part is arranged to selectively output the signals reproduced by the reproducing heads, and the pilot signal component included in the output of the switching part is used in controlling the positions of the reproducing heads relative to the recording medium.
    Type: Grant
    Filed: August 27, 1997
    Date of Patent: November 2, 1999
    Assignee: Canon Kabushiki Kaisha
    Inventor: Yukio Shimura
  • Patent number: 5978168
    Abstract: A head positioning system accurately positions a read/write head along a selected track of a rotating magnetic disk. In one aspect, servo information is embedded along the track with the centerline of the servo information offset a radial distance from the centerline of data stored or written along the track. The head positioning system micro-jogs the read/write head a first and a second radial distance from the centerline of servo information for a read operation and a write operation.
    Type: Grant
    Filed: February 11, 1997
    Date of Patent: November 2, 1999
    Assignee: Maxtor Corporation
    Inventors: Harlan Mathews, James A. Valent
  • Patent number: 5978162
    Abstract: A synchronous read channel is disclosed which samples an analog read signal from a magnetic read head positioned over a magnetic disk medium, filters the sample values according to a desired partial response, extracts timing information from the filtered sample values, and detects an estimated data sequence from the filtered sample values using a discrete time sequence detector. A Channel Quality circuit accumulates various signals generated by the read channel, such as sample errors, gain errors, timing errors, etc., for use in calibrating the read channel components and estimating the bit error rate.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: November 2, 1999
    Assignee: Cirrus Logic, Inc.
    Inventors: Richard T. Behrens, Kent D. Anderson, Alan J. Armstrong, Trent Dudley, Bill R. Foland, Neal Glover, Larry D. King
  • Patent number: 5978170
    Abstract: An index determining unit determines that a current position in a disk medium corresponds to a true index when reaching a true index pattern of servo information recorded in the disk medium. The determination is used for reading predetermined servo information so as to perform a servo control operation of a disk reading/writing head. The disk medium has the true index pattern in a first portion of the disk medium and also untrue index patterns of servo information in a predetermined number of second portions in proximity to the first portion along a track direction. The true index pattern and the untrue index patterns form a predetermined sequence.
    Type: Grant
    Filed: May 29, 1997
    Date of Patent: November 2, 1999
    Assignee: Fujitsu Limited
    Inventors: Yasunori Izumiya, Gen Ohshima, Taturo Sasamoto
  • Patent number: 5969896
    Abstract: A magnetic recording/reproducing device has an inductive write element provided with a coil and magnetic cores for recording information on a medium, a magnetoresistive read element for transducing a change in a magnetic field leaking from a medium, on which information is recorded, into an electrical signal, a detector for detecting an output signal of the read element, a bias field applying unit for applying a bias field to the read element, and a recording/reproducing operation controller for reproducing information based on an output signal from the read element and for controlling the recording current applying unit based on an inputted signal to record information. The recording/reproducing operation control unit has a stabilizing unit for controlling the bias field applying unit to make an absolute value of the bias field in a state where a magnetic field leaking from the medium is applied to the read element larger than that during a normal reproducing operation.
    Type: Grant
    Filed: January 6, 1997
    Date of Patent: October 19, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Kazuhiro Nakamoto, Yoshiaki Kawato, Hiroshi Fukui, Hiroyuki Hoshiya
  • Patent number: 5969893
    Abstract: Various data storage formats help to efficiently locate, read, and write user data stored on magnetic tape media. A tape is formatted by writing multiple segment-headers, free from any interleaved access of user data Adjacent segment-headers are spaced by a predetermined interval to define multiple data storage segments. Segment-headers all contain a unique key, which is copied into a key index to identify valid segments. After formatting, normal tape accesses can be performed. Without erasing any old headers or data, a new formatting scheme can be established by writing new segment-headers on the tape. The new segment-headers include a new unique key, replacing the previous key in the key index. Previous segment-headers stored on the tape are ignored, since they lack the updated key. Segments may be selectively grouped to provide independently addressable partitions. Mapping between segments and partitions can use a fixed relationship (e.g.
    Type: Grant
    Filed: July 23, 1997
    Date of Patent: October 19, 1999
    Assignee: International Business Machines Corporation
    Inventors: Robert Beverley Basham, Kirby Grant Dahman, Scott Milton Fry, Steven Douglas Johnson, Steven Bennett Wilson
  • Patent number: 5966258
    Abstract: A sampled amplitude read channel is disclosed for reading data recorded on a disk storage medium by detecting an estimated binary sequence from a sequence of discrete-time sample values generated by sampling pulses in an analog read signal from a read head positioned over the disk storage medium. The read channel comprises a variable gain amplifier for adjusting the magnitude of the analog read signal before sampling, and a discrete-time gain control loop for generating a gain control signal applied to the VGA in response to the discrete-time sample values. The discrete-time sample values may, or may not be, synchronized to a baud rate of the recorded data. For example, when reading the user data the discrete-time sample values are synchronous, and when reading a servo address mark (SAM) the sample values are asynchronous. As such, the discrete-time gain control loop of the present invention is programmable to operate in a synchronous or asynchronous mode.
    Type: Grant
    Filed: May 21, 1997
    Date of Patent: October 12, 1999
    Assignee: Cirrus Logic, Inc.
    Inventor: William G. Bliss
  • Patent number: 5966257
    Abstract: A synchronous read channel is disclosed which samples an analog read signal from a magnetic read head positioned over a magnetic disk medium, filters the sample values according to a partial response of the form (1-D)(1+D).sup.n where n>1, extracts timing information from the filtered sample values, and detects an estimated data sequence from the filtered sample values using a discrete time sequence detector.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: October 12, 1999
    Assignee: Cirrus Logic, Inc.
    Inventors: Richard T. Behrens, Alan J. Armstrong, Trent Dudley, Neal Glover, Larry D. King
  • Patent number: 5963384
    Abstract: A signal recording device is provided for transmitting recording data signals via a rotary transformer to a rotary drum having a rotary head for recording data so that control data may be transmitted in a shorter time period and resolution along the time axis may be improved. A 1-bit start bit SB and 2-bit mode setting bits PD are followed by 3-bit group bits GP and 3-bit channel bits CL for a single bit mode, by 3-bit group bits GP and an 8-bit bit patterns BP for a multi-bit mode and by a 4-bit channel number DAN and 8-bit data DAD for D/A data. An even parity PE is appended for each of the respective modes. A continuation flag CF is further appended for the single-bit mode and the multi-bit mode.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: October 5, 1999
    Assignee: Sony Corporation
    Inventors: Minoru Kawahara, Hitoshi Tsujii, Kazuo Tomita
  • Patent number: 5963389
    Abstract: The tape transport system acquires telemetry information pertaining to the tape medium at a position in advance of the associated tape segment passing over the movable read head. The advance telemetry information includes tape motion and position information which is used to identify both physical defects in the tape medium and misalignment of the tape medium with respect to the movable read head. The advance telemetry information are used to adjust the tape speed and the position of the movable read head with respect to the tape medium as the tape moves ahead to encounter the read head. This compensation can significantly reduce the data loss errors induced by tape speed and tape tracking errors.
    Type: Grant
    Filed: August 8, 1997
    Date of Patent: October 5, 1999
    Assignee: Storage Technology Corporation
    Inventors: Matthew Peter Wojciechowski, Joe Kent Jurneke
  • Patent number: 5963382
    Abstract: A supplied time code is multiplied to generate detailed time data. The detailed time data are latched at a given time in an input signal. The latched time data are converted into converted time data having a given data format. The converted time data are recorded in the same transmission path as the output signal.
    Type: Grant
    Filed: April 12, 1996
    Date of Patent: October 5, 1999
    Assignee: Sony Corporation
    Inventor: Fumiyoshi Abe
  • Patent number: 5959799
    Abstract: A method and apparatus for tracking control of a magnetic head having information signals and tracking signals recorded on a plurality of slanted tracks measures a time duration from a time when a rotary head drum passes a reference position to a time when the head starts to reproduce the tracking signal. The measured time duration and a reference value are compared to determine whether the difference falls within a predescribed range and the relative speed between the transporting speed of the tape and the peripheral speed of the rotary head drum is controlled based on the comparison results when the determination results falls within the prescribed ranged. The reference value is continuously monitored and updated from a memory when the measured difference exceeds a predetermined value.
    Type: Grant
    Filed: December 28, 1995
    Date of Patent: September 28, 1999
    Assignee: Sony Corporation
    Inventor: Yoshihiko Deoka
  • Patent number: 5959794
    Abstract: A method and apparatus is disclosed for determining the remanent noise in a magnetic medium by DC saturation of a region thereof and measurement of the remaining DC magnetization. Conventional recording transducers may be used to determine the remanent noise. Upon determination, the remanent noise may then be compensated for in either or both of the record and playback modes for all varieties of magnetic media including, videotapes, cassette tapes, etc.
    Type: Grant
    Filed: October 25, 1996
    Date of Patent: September 28, 1999
    Assignee: Washington University
    Inventors: Ronald Scott Indeck, Marcel Wettstein Muller, Joseph Andrew O'Sullivan
  • Patent number: 5959797
    Abstract: A magnetic recording apparatus according to the present invention comprises a magnetic recording medium having a plurality of servo sectors and a plurality of data sectors on the tracks, first sensing means for sensing a first servo sector located before a target data sector and, on the basis of the first servo sector, sensing the target data sector, judging means for judging whether or not the first sensing means has sensed the first servo sector, and second sensing means for sensing the target data sector on the basis of a second servo sector different from the first servo sector, in response to the judging means judging that the first sensing means has failed to sense the first servo sector.
    Type: Grant
    Filed: June 24, 1997
    Date of Patent: September 28, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Imai, Fubito Igari
  • Patent number: 5959802
    Abstract: A method and apparatus for recording and/or reproducing signal on or from a recording medium includes correct tracking servo signals which may be produced so that tracking errors may be detected correctly. The pilot signal from a recording amplifier 3, produced by frequency-dividing system clocks by a frequency divider 2, is recorded on the recording medium by a servo head 21 at the timing of a timing signal GP.sub.1. A tracking servo signal, obtained by reproducing the pilot signal by a recording/reproducing head 22, delaying the resulting signal by a delay circuit 4 and phase-shifting the resulting delayed signal by a phase shifting unit 5, is recorded at the timing of a timing signal GP.sub.2. The pilot signal and the tracking servo signal are reproduced by the recording/reproducing head 22 and the pilot signal is delayed by the delay circuit 4.
    Type: Grant
    Filed: July 11, 1995
    Date of Patent: September 28, 1999
    Assignee: Sony Corporation
    Inventor: Tsuguo Sato
  • Patent number: 5949600
    Abstract: A magnetic recording and reproducing apparatus, including a probe made of a ferromagnetic film movable relative to a magnetic recording medium while having a distal end facing the magnetic recording medium; a head section having a recording element for recording a signal on the magnetic recording medium and a reproducing element including at least a probe for reproducing a signal recording on the magnetic recording medium; and a head slider for mounting the head section.
    Type: Grant
    Filed: September 6, 1996
    Date of Patent: September 7, 1999
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Junichi Akiyama, Yoichiro Tanaka
  • Patent number: 5946153
    Abstract: A magnetic recording system utilizing a magnetic recording disk. In some embodiments, one magnetic surface is utilized with an associated read/write transducer supported by a load beam. In other embodiments, the disk has a plurality of magnetic surfaces, each having an associated read/write transducer for reading and writing data in tracks in a plurality of zones and an associated load beam for supporting and positioning the respective read/write transducer at a plurality of locations above the respective surface. In one embodiment, the radial boundaries of the zones and read/write frequency for each zone are defined as a function of the number of available tracks on the recording surface. In another embodiment, the radial boundaries of the zones and read/write frequency for the zones are defined as a function of the read/write performance of the read/write transducer with respect to its associated magnetic surface.
    Type: Grant
    Filed: January 30, 1996
    Date of Patent: August 31, 1999
    Assignee: Mobile Storage Technology Inc.
    Inventors: Bruce D. Emo, Brian D. Wilson, Nelson Chenkin
  • Patent number: 5946155
    Abstract: Three kinds of stop patterns are recorded at the same cylinder position of at least three recording surfaces of disk media. Each pattern is a division pattern in which one circumference is divided into two portions and which are recorded therein. Phases of the division patterns are sequentially deviated in the circumferential direction every 120.degree.. When a motor is activated, the motor stop position is detected on the basis of the stop patterns of the disk media and activating conditions to rotate the motor in a predetermined direction, thereby activating the brushless DC motor having no Hall sensor.
    Type: Grant
    Filed: December 23, 1996
    Date of Patent: August 31, 1999
    Assignee: Fujitsu Limited
    Inventor: Kazunori Tochiyama
  • Patent number: 5940237
    Abstract: A disk apparatus includes a disk medium for recording information in a track provided on the disk medium, a rotation circuit for rotating the disk medium, and a head for recording-and-reproducing to-and-from the disk medium. The head further includes a recording head element and a reproducing head element arranged along the track at a given gap from each other. The disk apparatus further includes a driving control circuit for swinging the head to a given position in a radial direction of the disk medium. In the disk apparatus, the disk medium is formatted by changing a track pitch in the radial direction of the disk medium.
    Type: Grant
    Filed: July 7, 1997
    Date of Patent: August 17, 1999
    Assignee: Fujitsu Limited
    Inventor: Masahiro Takagi
  • Patent number: 5930063
    Abstract: A variable-speed playback apparatus and method for reproducing digital video signals recorded in tracks of a recording medium, such as a magnetic tape. A track number and a synchronization block number may be obtained from the magnetic tape and utilized to form a trace phase. Such trace phase is compared to a reference trace phase so as to obtain a phase error which is used to control the tape speed. As a result, the tape traveling speed may be controlled with a relatively high accuracy.
    Type: Grant
    Filed: October 12, 1995
    Date of Patent: July 27, 1999
    Assignee: Sony Corporation
    Inventors: Toshitaka Yoshihiro, Masahiko Nagumo, Masato Yamaoka