David A Magee

US Patent:

6522494, Feb 18, 2003

Filed:

Sep 30, 1999

Appl. No.:

09/409628

Inventors:

David P. Magee - Plano TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 2102

US Classification:

360 75

Abstract:

A method for writing servo patterns on a hard disk drive disk in a hard disk drive assembly. The assembly includes a disk having at least one magnetic surface in which a reference pattern has been written, determining a reference track. Also included is an actuator having a shaft engaged with the disk to provide rotational motion to the disk, an actuator arm, and a micro-actuated read/write head mounted on the actuator arm. The method includes the following steps. First, the read/write head is used to position the actuator arm at a first fixed position over the reference track. The actuator arm is maintained at the first fixed position while the read/write head is used to write a second servo pattern, determining a second track. The read/write head is used to position the actuator arm at a second fixed position over the second track. Then, the actuator arm is maintained at the second fixed position while the read/write head is used to write a third servo pattern.

US Patent:

6563885, May 13, 2003

Filed:

Oct 24, 2001

Appl. No.:

09/999721

Inventors:

David Patrick Magee - Plano TX
Srinath Hosur - Plano TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04L 2714

US Classification:

375316, 375278, 375284, 375285, 375346, 455296

Abstract:

A system and method facilitate estimating noise in a received signal. The received signal includes a plurality of data tones. Noise is estimated for a selected subset of data tones for each data burst, such that noise estimates for all data tones can be computed over a plurality of data bursts. As a result of spreading the noise estimates over more than one burst, the overall computations associated with obtaining the noise estimates can be reduced based on the size of the respective subsets. The updated data tone noise estimates further can be employed in subsequent processing, such as in beamforming calculations.

US Patent:

6618217, Sep 9, 2003

Filed:

Feb 23, 1999

Appl. No.:

09/256467

Inventors:

Mark W. Heaton - Irving TX
David P. Magee - Plano TX
Michael T. DiRenzo - Coppell TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 5596

US Classification:

360 7703, 360 75, 3602945

Abstract:

A position sensor includes a stationary platform and a moveable platform. The position sensor further includes at least one beam coupling the moveable platform to the stationary platform. The at least one beam includes piezoresistive material that is positioned tolprovide an indication of a movement of the moveable platform relative to the stationary platform.

US Patent:

6751043, Jun 15, 2004

Filed:

Dec 3, 2001

Appl. No.:

09/998757

Inventors:

David P. Magee - Plano TX
Michael T. DiRenzo - Coppell TX
Mark W. Heaton - Irving TX

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

G11B 5596

US Classification:

360 7702, 360 7806

Abstract:

This invention comprises an architecture for voltage mode control of a voice coil motor in a hard disk drive. In contrast to conventional current mode control, coil current is not sensed or measured, which simplifies the feedback design with less hardware required in the implementation. Common design methodologies for the square root velocity profile, linear velocity profile and regulator/estimator control system designs can be migrated from the current mode architecture to the voltage mode architecture.

US Patent:

6917311, Jul 12, 2005

Filed:

Aug 11, 2003

Appl. No.:

10/639418

Inventors:

Srinath Hosur - Plano TX, US
Anuj Batra - Dallas TX, US
Srikanth Gummadi - Rohnert Park CA, US
David P. Magee - Plano TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H03M007/00

US Classification:

341 50, 341 51, 375347

Abstract:

For use with a multiple-input, multiple-output (MIMO) transmitter, an orthogonal preamble encoder, a method of encoding orthogonal preambles and a communication system incorporating the encoder or the method. In one embodiment, the encoder includes: (1) a preamble supplement generator configured to provide a first long sequence preamble supplement to a first transmit antenna of the MIMO transmitter and (2) a preamble supplement coordinator coupled to the preamble supplement generator and configured to provide a second long sequence preamble supplement to a second transmit antenna of the MIMO transmitter, at least a portion of the second long sequence preamble supplement being a negation of the first long sequence preamble supplement.

US Patent:

7020222, Mar 28, 2006

Filed:

Oct 24, 2001

Appl. No.:

10/002318

Inventors:

David Patrick Magee - Plano TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H03D 1/00
H04L 27/06

US Classification:

375340, 375345

Abstract:

Systems and methods for determining offset phasors are disclosed. An offset vector is computed from a current channel impulse response and a previous channel impulse response. A first vector and a second vector are simultaneously and iteratively rotated in opposite directions to determine an offset phasor. A first vector of the pair of vectors is initialized with a constant value for its x coordinate and a zero for its y coordinate. A second vector of the pair of vectors is initialized with the x and y coordinates of the offset vector. The vectors are rotated in opposite directions using shift operations for a specific number of iterations. After the final rotation, the y coordinate of the second vector has become zero and the x and y coordinates of the first vector correspond to the sine and cosine of the angle formed by the offset vector. The cosine and sine terms form the real and imaginary parts of the offset phasor.

US Patent:

7023931, Apr 4, 2006

Filed:

Nov 5, 2001

Appl. No.:

10/007142

Inventors:

David Patrick Magee - Plano TX, US
Srinath Hosur - Plano TX, US
David James Love - Garland TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04L 23/02
H04L 5/12

US Classification:

375262, 370 20, 370339, 370442, 375261, 375298, 375316, 455 60, 714786, 714794, 714795

Abstract:

Methods and systems for performing iterative soft slicing methods are disclosed. A data signal is received and processed into individual data tones. A noise estimator provides noise estimates for each data tone. A beamformer utilizes the noise estimates to provide first and second components of a constellation point estimate. A ratio of the first and second components corresponds to the constellation point estimate. A soft slicer uses outputs from the beamformer and noise estimator to determine weighted constellation points without dividing the first component by the second component.

US Patent:

7088791, Aug 8, 2006

Filed:

Oct 19, 2001

Appl. No.:

10/082826

Inventors:

David Patrick Magee - Plano TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04L 27/06

US Classification:

375340, 708404

Abstract:

Systems and methods are provided for performing signal processing on communication data utilizing scale reduced Fast Fourier Transform computations. The present invention provides scaling in a Fast Fourier Transform computation at stages where it is determined that bit growth is present and omits scaling at stages where it is determined that bit growth is absent. The determination is based on the characteristics of the input signal. The determination can be made off-line by modeling and/or simulation or in real-time by analyzing the input signal to determine stages at which bit growth is present and/or absent and setting the stage scaling accordingly.