Patents by Inventor David E. Norton
David E. Norton 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).
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Patent number: 7362525Abstract: Apparatuses and methods for detecting reference marks on magnetic data storage mediums are described herein. In one variation, the apparatus comprises a magnetic servo position demodulator operable to extract information from the magnetic data storage medium utilizing Partial Response/Maximum Likelihood (PRML) technique. Synchronization marks stored within the PRML channel is then detected utilizing a digital filter. For each of the detected synchronization mark, a further refined position of the synchronization mark can be determined utilizing a mathematical prediction model.Type: GrantFiled: July 22, 2005Date of Patent: April 22, 2008Assignee: Quantum CorporationInventor: David E. Norton, Jr.
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Publication number: 20080030899Abstract: According to one aspect of the present invention a data storage tape is provided. In one example, the data storage tape comprises a substrate having a first recording layer and a second recording layer disposed on opposite sides of the substrate. Further, the first and second recording layers are uni-directional, and oriented in opposite directions on the first and second sides. In one example, the recording material includes an Advance Metal Evaporated (AME), and is generally suitable for vertical recording. Additionally, the tape may include various other layers and materials, for example, a coating on one or both major sides for reducing adhesion to the opposite major side (when wound on a cartridge or take-up reel, for example).Type: ApplicationFiled: August 7, 2006Publication date: February 7, 2008Applicant: Quantum CorporationInventor: David E. Norton
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Patent number: 6697209Abstract: In a helical scan recording system, magnetic tape (31) is transported by a tape transport (98) proximate a rotating scanner (85). The scanner has a pair of read heads (82) mounted thereon, e.g., a first read head and a second read head, which travel in a helical direction on the magnetic tape in view of the transport of the tape and rotation of the scanner. A synchronization detection system (38) determines a first synchronization mark detection time at which a first synchronization mark is read by the first read head from the first track, and a second synchronization mark detection time at which a synchronization mark read by the second read head from the second track. A position error signal generator (100) develops a position error signal (PES) based upon a difference between the first synchronization mark detection time and the second synchronization mark detection time.Type: GrantFiled: January 18, 2001Date of Patent: February 24, 2004Assignee: Exabyte CorporationInventors: Timothy C. Hughes, David E. Norton, Jr.
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Patent number: 6433945Abstract: A transformer-coupled tape drive (30) allows operation using a direct current (DC) content code. Usage of the DC content code is facilitated by a compensation circuit (240) which corrects timing distortion caused by the DC content code. The compensation circuit comprises both an emulation circuit (306) and a delay circuit (302). The emulation circuit (306) emulates a high pass filter action of a transformer (220) to provide an emulated high pass filter response signal (WD_HP). The delay circuit (302) modifies the modify timing of the write data signal in accordance with the emulated high pass filter response signal to output a compensated write data signal to the transformer (220).Type: GrantFiled: November 9, 2000Date of Patent: August 13, 2002Assignee: Exabyte CorporationInventor: David E. Norton, Jr.
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Publication number: 20020080519Abstract: In a helical scan recording system, magnetic tape (31) is transported by a tape transport (98) proximate a rotating scanner (85). The scanner has a pair of read heads (82) mounted thereon, e.g., a first read head and a second read head, which travel in a helical direction on the magnetic tape in view of the transport of the tape and rotation of the scanner. A synchronization detection system (38) determines a first synchronization mark detection time at which a first synchronization mark is read by the first read head from the first track, and a second synchronization mark detection time at which a synchronization mark read by the second read head from the second track. A position error signal generator (100) develops a position error signal (PES) based upon a difference between the first synchronization mark detection time and the second synchronization mark detection time.Type: ApplicationFiled: January 18, 2001Publication date: June 27, 2002Inventors: Timothy C. Hughes, David E. Norton
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Patent number: 6344981Abstract: A power supply circuit (120) for supplying power to a load (130) comprises a regulator (122), a switching transistor (124) connected to the regulator; and a power transformer (126) connected between the switching transistor and the load. The regulator is of a type that requires feedback regarding the amount of voltage supplied to the load. In accordance with the present invention, a feedback signal to the regulator is generated by monitoring an input to the power transformer. In particular, a voltage signal related to a voltage on the primary of the power transformer after a voltage spike is applied as the feedback signal to the regulator. A peak detector (140) detects the to voltage spike and applies the voltage signal to the regulator. A peak detector reset circuit (142) resets the peak detector. In one example context of usage, a variable air gap exists between a stationary primary of the power transformer and a secondary of the power transformer.Type: GrantFiled: January 27, 2000Date of Patent: February 5, 2002Assignee: Exabyte CorporationInventors: David E. Norton, Jr., Christopher J. Wells, John S. Gablenz
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Patent number: 6343336Abstract: Method and apparatus are provided for enabling a reproducing apparatus, having a read channel which utilizes a second transfer function, to recover accurately data which has been recorded on a medium with a first transfer function. A compatibility circuit (73) derives a data rate from the medium, and causes the read channel to sample the data steam acquired from the medium at a multiple of the data rate, thereby creating a multiply-sampled data stream. Further, the compatibility circuit manipulates the multiply-sampled data stream to generate a deformatted read data stream. In particular, a deformatter (62) of the compatibility circuit selects only some bits of the multiply-sampled data stream to generate a modified data stream; and the applies a reverse of the first transfer function to generate a deformatted read data stream.Type: GrantFiled: January 27, 2000Date of Patent: January 29, 2002Assignee: Exabyte CorporationInventors: David E. Norton, Jr., Mark H. Moyer
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Patent number: 5455720Abstract: Positive and negative peaks of the differential pulses produced by a differential head of a disk drive are detected. The respective peaks, which represent the positive and negative peaks of the pulses, are compared to a set of reference levels and, depending upon the relationship of those peaks with the reference levels, a gain error or an offset error is indicated. If the positive pulse peaks and negative pulse peaks exhibit substantially similar relationships with respect to the reference levels, a gain error is indicated. However, if the positive pulse peaks and negative pulse peaks exhibit dissimilar relationships with respect to the reference levels, an offset error is indicated.Type: GrantFiled: October 27, 1994Date of Patent: October 3, 1995Assignee: Fujitsu LimitedInventor: David E. Norton, Jr.
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Patent number: 5388010Abstract: A peak detector for detecting accurate peaks of pulses recovered from a magnetic disk in the presence of residual magnetism by a magnetic head, but without the deleterious effects of such residual magnetism. The head supplies differential pulses as respective pulse trains to first and second peak detectors, respectively. The peaks detected in the first train of differential pulses are combined with the peaks detected in the second train, and an output signal produced as a function of the combined peaks is indicative of the pulse peaks. The respective peaks, which represent the positive and negative peaks of the pulses, are compared to a set of reference levels and, depending upon the relationship of those peaks with the reference levels, a gain error or an offset error is indicated. If the positive pulse peaks and negative pulse peaks exhibit substantially similar relationships with respect to the reference levels, a gain error is indicated.Type: GrantFiled: December 13, 1993Date of Patent: February 7, 1995Assignee: Fujitsu LimitedInventor: David E. Norton, Jr.
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Patent number: 5325241Abstract: A write precompensation circuit employs a frequency synthesizer for providing a variable timing signal linked to variable transfer rate in a track zone recording system of a disk drive. The synthesizer also provides an operating frequency current sense signal that is used to generate bit shift of data bits being recorded. A ramp voltage on a ramp capacitor and a logic signal from a bit shift decision circuit are determinative of the magnitude and direction of bit shift, early or late. The VCO and its capacitor are formed on the same IC chip as the ramp capacitor thereby minimizing mismatch due to tolerances inherent in production and operation of electrical components.Type: GrantFiled: June 14, 1991Date of Patent: June 28, 1994Assignee: Fujitsu LimitedInventors: Rodney A. L. Mattison, David E. Norton, Jr.
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Patent number: 5315168Abstract: A peak hold circuit includes an operational amplifier in a continually closed feedback loop and a peak hold capacitor with a discharge path. An input signal is received at a first input of the amplifier, and the output of the amplifier is fed to a first transistor then fed back therefrom to a second input of the amplifier. A current sink is coupled to the first transistor for drawing a current therefrom so that the feedback signal is continually provided to the second amplifier input, ensuring that the amplifier is in a continually closed feedback loop. The output of the amplifier is supplied to the peak hold capacitor through a second transistor.Type: GrantFiled: April 28, 1993Date of Patent: May 24, 1994Assignee: Fujitsu LimitedInventor: David E. Norton, Jr.
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Patent number: 5293276Abstract: A plurality of data sequences having patterns distinguishable from informational data are recorded as a servo mark portion of servo information on a disk. Upon decoding a predetermined number of these data sequences, a determination is made as to whether an accurately located servo mark has been detected. The detected servo mark provides a reference from which the beginning of recorded servo burst data can be located, thereby enabling all of the servo burst data to be read. The presence of defects does not inhibit the detection of the servo mark.Type: GrantFiled: January 24, 1992Date of Patent: March 8, 1994Assignee: Fujitsu LimitedInventors: Mary E. Dunn, David E. Norton, Jr.
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Patent number: 4868470Abstract: A true average peak detector includes an input capacitor having a capacitance C and an output capacitor having a capacitance nC. N voltage samples are successively stored on the input capacitor and are transferred to the output capacitor without discharging the latter. The output voltage from the accumulated charge on the output capacitor is equal to a true average of the voltages of the n samples.Type: GrantFiled: May 20, 1988Date of Patent: September 19, 1989Assignee: MiniScribe CorporationInventors: Nicholas J. Bucska, David E. Norton, Jr.
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Patent number: 4746821Abstract: A constant phase diode limiter has a pair of oppositely poled diodes in series between the primary of an output transformer and an input terminal. The junction of the diodes is connected to a voltage source through a resistor and inductor. A capacitor having the same value as the capacitance of each of the diodes when nonconducting is connected between the input and the secondary winding of the output transformer. The secondary winding of the output transformer is connected in series between the output terminal and the latter capacitor.Type: GrantFiled: February 14, 1986Date of Patent: May 24, 1988Assignee: Adams-Russell Co. Inc.Inventor: David E. Norton
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Patent number: 4622599Abstract: A write data transition detector is provided connected across a thin film write head and write current generator and is responsive to the fractional voltage drops across the head resulting from the fractional amperage currents passed by the write generator through the head. Circuits in the detector adjust the gain of the voltage difference across the head, remove voltage spikes induced by changes in current across the head and time the period between consecutive current reversals of sufficient magnitude. The timing is controlled by means of a hysteresis circuit which switches from an existing state to an alternate state only when there is a satisfactorily large reversal of current across the write head. A timing circuit connected with the hysteresis circuit capacitively times the length of the period the hysteresis circuit remains in its existing state and outputs a fault indication current when this period exceeds the maximum period between transitions allowed by the encoding scheme employed.Type: GrantFiled: November 19, 1984Date of Patent: November 11, 1986Assignee: Storage Technology CorporationInventor: David E. Norton, Jr.