Patents by Inventor Jaydip Bhaumik
Jaydip Bhaumik 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: 9881637Abstract: An apparatus for microwave-assisted magnetic recording includes a magnetic write head operable to write data to a magnetic storage medium. The apparatus includes a spin-torque microwave oscillator coupled to the magnetic write head and operable to provide microwave radiation to the magnetic storage medium. The apparatus includes a driver circuit in communication with the magnetic write head. The driver circuit is operable to dynamically modulate bias current provided to the spin-torque microwave oscillator in sympathy with data being written to the magnetic storage medium by the magnetic write head.Type: GrantFiled: February 17, 2017Date of Patent: January 30, 2018Assignee: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.Inventors: Ross Wilson, Andrew Krebs, Jaydip Bhaumik, Greg Starr, Scott O'Brien
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Patent number: 9715887Abstract: A storage system includes a magnetic write head, a magnetic storage medium, a channel circuit comprising a write data output, wherein the channel circuit is operable to process write data to be recorded on the magnetic storage medium by the magnetic write head, and a preamplifier operable to receive the write data from the channel circuit, wherein the preamplifier comprises a number of register pages configured to store pattern dependent write current characteristics for a variety of magnet lengths, and wherein the preamplifier is operable to retrieve the write current characteristics based on magnet lengths and to record data bits on the magnetic storage medium using the write current characteristics.Type: GrantFiled: December 28, 2015Date of Patent: July 25, 2017Assignee: AVAGO TECHNOLOGIES GENERAL IP (SINGAPORE) PTE. LTD.Inventors: Ross S. Wilson, Peter J. Windler, Bruce A. Wilson, Jaydip Bhaumik, Scott M. O'Brien, Jason P. Brenden, Jeffrey A. Gleason, Cameron C. Rabe
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Publication number: 20170186448Abstract: A storage system includes a magnetic write head, a magnetic storage medium, a channel circuit comprising a write data output, wherein the channel circuit is operable to process write data to be recorded on the magnetic storage medium by the magnetic write head, and a preamplifier operable to receive the write data from the channel circuit, wherein the preamplifier comprises a number of register pages configured to store pattern dependent write current characteristics for a variety of magnet lengths, and wherein the preamplifier is operable to retrieve the write current characteristics based on magnet lengths and to record data bits on the magnetic storage medium using the write current characteristics.Type: ApplicationFiled: December 28, 2015Publication date: June 29, 2017Inventors: Ross S. Wilson, Peter J. Windler, Bruce A. Wilson, Jaydip Bhaumik, Scott M. O'Brien, Jason P. Brenden, Jeffrey A. Gleason, Cameron C. Rabe
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Patent number: 9437219Abstract: An apparatus for two-dimensional magnetic recording includes a storage medium, an array of magnetoresistive read heads disposed adjacent the storage medium and spaced to read a data track, a number of leads connected to the array of magnetoresistive read heads, and number of bias circuits connected to the array of read heads by the leads. The bias circuits can be configured to independently bias each of the array of read heads with the array of read heads connected in series or in parallel.Type: GrantFiled: September 10, 2015Date of Patent: September 6, 2016Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.Inventors: Ross S. Wilson, Scott M. O'Brien, Jeffrey A. Gleason, Jason P. Brenden, Jaydip Bhaumik, David Fitzgerald
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Patent number: 9401175Abstract: An apparatus for correcting crosstalk in an array reader magnetic recording system includes an array reader comprising a number of read heads operable to read data from a magnetic storage medium, a preamplifier configured to amplify the signals from the read heads, and a crosstalk correction circuit configured to reduce crosstalk between signals from the read heads.Type: GrantFiled: July 21, 2015Date of Patent: July 26, 2016Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.Inventors: Jaydip Bhaumik, Jeffrey A. Gleason, Scott M. O'Brien, Travis Oenning, Ross S. Wilson
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Patent number: 8233229Abstract: Various systems and methods for reducing cross coupling in proximate signals are disclosed. As one example, a system for reducing cross-coupling in adjacent signals that includes an active slew rate limiter circuit is disclosed. The active slew rate limiter circuit is operable to receive an input signal, and to provide an output signal based on the input signal with a controlled slew rate. In some cases, such systems may be included within a storage device that includes a read head. In such cases, the systems may operate to assure a substantially constant power dissipation within the read head.Type: GrantFiled: February 16, 2006Date of Patent: July 31, 2012Assignee: Agere Systems Inc.Inventors: Robert J. Wimmer, Ram S. Narayan, Jaydip Bhaumik, Michael J. Peterson, David W. Kelly
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Publication number: 20080297093Abstract: Various systems and methods for reducing cross coupling in proximate signals are disclosed. As one example, a system for reducing cross-coupling in adjacent signals that includes an active slew rate limiter circuit is disclosed. The active slew rate limiter circuit is operable to receive an input signal, and to provide an output signal based on the input signal with a controlled slew rate. In some cases, such systems may be included within a storage device that includes a read head. In such cases, the systems may operate to assure a substantially constant power dissipation within the read head.Type: ApplicationFiled: February 16, 2006Publication date: December 4, 2008Inventors: Robert J. Wimmer, Ram S. Narayan, Jaydip Bhaumik, Michael J. Peterson, David W. Kelly
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Patent number: 7034478Abstract: A three-phase spindle motor has three terminals each driven with pulse width modulated signals. Rotation of the motor is controlled by iteratively measuring an electrical period of the motor, determining a rotational position of the motor, and synchronizing the sinusoidal pulse width modulation of the spindle motor with the measured electrical period. The electrical period of the motor is measured by detecting zero crossings in the a back electromotive force induced at a first terminal of the motor and determining the time between successive zero crossings. The rotation position of the motor is determined based upon the last measured electrical period and a location of last detected zero crossing. The zero crossings are detected by selecting a time window during which the back electromotive force signal is sensed for zero crossings. The time window is selected as a function of the last measured electrical period and the rotational position of the motor.Type: GrantFiled: September 30, 2004Date of Patent: April 25, 2006Assignee: Agere Systems Inc.Inventors: Jaydip Bhaumik, Jason P. Brenden, Dames A. Dahlberg, Michael Peterson, Ross Wilson
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Publication number: 20060066280Abstract: A three-phase spindle motor has three terminals each driven with pulse width modulated signals. Rotation of the motor is controlled by iteratively measuring an electrical period of the motor, determining a rotational position of the motor, and synchronizing the sinusoidal pulse width modulation of the spindle motor with the measured electrical period. The electrical period of the motor is measured by detecting zero crossings in the a back electromotive force induced at a first terminal of the motor and determining the time between successive zero crossings. The rotation position of the motor is determined based upon the last measured electrical period and a location of last detected zero crossing. The zero crossings are detected by selecting a time window during which the back electromotive force signal is sensed for zero crossings. The time window is selected as a function of the last measured electrical period and the rotational position of the motor.Type: ApplicationFiled: September 30, 2004Publication date: March 30, 2006Inventors: Jaydip Bhaumik, Jason Brenden, Dames Dahlberg, Michael Peterson, Ross Wilson
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Publication number: 20060066279Abstract: A motor controller provides pulse width modulated drive signals to a motor. A digital demand code for controlling motor speed is input to the motor controller. A dither generator generates a digital dither value, which an adder adds to the demand code to generate a dithered demand code. A position determining circuit determines a rotational position of the motor. A pulse width modulation controller generates pulse width modulated drive signals with duty cycles controlled as a function of a stored set of waveform coefficients, the dithered demand code, and the rotational position of the motor.Type: ApplicationFiled: September 30, 2004Publication date: March 30, 2006Applicant: Agere Systems Inc.Inventors: Jason Brenden, James Dahlberg, Jaydip Bhaumik
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Patent number: 7012396Abstract: A motor controller provides pulse width modulated drive signals to a motor. A digital demand code for controlling motor speed is input to the motor controller. A dither generator generates a digital dither value, which an adder adds to the demand code to generate a dithered demand code. A position determining circuit determines a rotational position of the motor. A pulse width modulation controller generates pulse width modulated drive signals with duty cycles controlled as a function of a stored set of waveform coefficients, the dithered demand code, and the rotational position of the motor.Type: GrantFiled: September 30, 2004Date of Patent: March 14, 2006Assignee: Agere Systems Inc.Inventors: Jason P. Brenden, James A. Dahlberg, Jaydip Bhaumik
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Patent number: 6584422Abstract: A method and apparatus are provided for optimizing calibration of a tunable filter over a wide range of frequencies in a data channel of a direct access storage device (DASD). Calibration codes are received for low corner frequency, banding, and high corner frequency. A programmable diode is provided with a DC portion and a tunable digital-to-analog converter (DAC). A calibration control current is generated for calibrating the tunable filter utilizing the programmable diode and the calibration codes. The programmable diode is used to vary the calibration control current to calibrate the tunable filter to a correct low corner frequency and high corner frequency. The programmable diode can be programmed over a large range.Type: GrantFiled: May 24, 2001Date of Patent: June 24, 2003Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Jaydip Bhaumik, Raymond Alan Richetta
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Publication number: 20020177966Abstract: A method and apparatus are provided for optimizing calibration of a tunable filter over a wide range of frequencies in a data channel of a direct access storage device (DASD). Calibration codes are received for low corner frequency, banding, and high corner frequency. A programmable diode is provided with a DC portion and a tunable digital-to-analog converter (DAC). A calibration control current is generated for calibrating the tunable filter utilizing the programmable diode and the calibration codes. The programmable diode is used to vary the calibration control current to calibrate the tunable filter to a correct low corner frequency and high corner frequency. The programmable diode can be programmed over a large range.Type: ApplicationFiled: May 24, 2001Publication date: November 28, 2002Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Jaydip Bhaumik, Raymond Alan Richetta
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Patent number: 6469856Abstract: A system and method provides for calibrating a corner frequency of a tunable filter coupled to a read channel of a data storage system to a desired frequency. A signal having a frequency equal to the target corner frequency is generated. A gain of the signal is adjusted to a gain threshold. The gain of the signal is then increased from the gain threshold by a pre-established amount, such as by 3 dB. The corner frequency of the signal is shifted until the gain of the signal is substantially equal to the gain threshold, at which point the corner frequency of the tunable filter is calibrated to the desired frequency. The signal generated is a peak-detectable signal. The corner frequency of a tunable filter may be a low or high corner frequency appropriate for filtering a data signal or a servo signal. The corner frequency calibration circuitry may be implemented in-situ the read channel circuitry of a data storage system.Type: GrantFiled: May 12, 2000Date of Patent: October 22, 2002Assignee: International Business Machines CorporationInventors: Chad Edward Mitchell, Rick Allen Philpott, Jaydip Bhaumik, Raymond Alan Richetta
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Patent number: 6429988Abstract: A system and method are provided for calibrating a corner frequency of a tunable filter using an ADC code difference method. A method for calibrating a corner frequency of a tunable filter in a direct access storage device includes generating a signal having a frequency within a pass band of the tunable filter to be passed to the tunable filter. The gain of the signal is adjusted to a first threshold level. The corner frequency of the signal is shifted to a second threshold level, whereby the corner frequency of the tunable filter is calibrated at a desired frequency. A system for calibrating a corner frequency of a tunable filter in a direct access storage device includes calibrate control logic coupled to a tunable filter. A signal source generating a signal having a frequency within a pass band of the tunable filter to be passed to the tunable filter is coupled to the tunable filter by a variable gain amplifier. An analog-to-digital converter (ADC) is coupled to the tunable filter.Type: GrantFiled: September 22, 2000Date of Patent: August 6, 2002Assignee: International Business Machines CorporationInventors: Jaydip Bhaumik, Chad Edward Mitchell, Rick Allen Philpott, Raymond Alan Richetta
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Patent number: 6400518Abstract: A circuit arrangement for correcting magneto-resistive head asymmetry includes a shift circuit which receives a read signal from a magneto-resistive head, and a polarity signal indicative of the polarity of any asymmetry of the read signal. Depending on the polarity of the asymmetry, the shift circuit either adds or subtracts a shift voltage to the read signal to produce a shifted read signal. The shift circuit outputs the read signal, the shifted read signal, and the shift voltage. First, second and third gain circuits are provided, which receive the read signal, the shifted read signal, and the shift voltage, respectively, and which each receive a respective control signal. The first, second and third gain circuits provide respective outputs amplified proportionally based on the respective control signals. Control circuitry provides the polarity signal to the shift circuit and the respective control signals to the first, second and third gain circuits, based on an amount of correction required.Type: GrantFiled: November 1, 2000Date of Patent: June 4, 2002Assignee: International Business Machines CorporationInventors: Jaydip Bhaumik, Robert Andrew Kertis, Klaas Berend Klaassen, Raymond Alan Richetta, Jacobus Cornelis Leonardus Van Peppen