Patents by Inventor Eric James Tree

Eric James Tree 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).

  • Method and apparatus for channel equalization with a digital FIR filter using a pseudo random sequence
    Patent number: 6937650
    Abstract: A method and apparatus are provided for channel equalization with a digital finite impulse response (DFIR) filter using a pseudo random sequence. A readback signal of a pseudo random bit sequence is obtained. Samples are obtained from the readback signal of the pseudo random bit sequence. Tap gradients are calculated responsive to the obtained samples. The tap weights of the digital finite impulse response (FIR) filter are modified responsive to the calculated tap gradients. Dibit samples and error samples are obtained from the readback signal of the pseudo random bit sequence and applied to a tap gradients calculator. Tap gradients are calculated by a bitwise multiplier and accumulation tap gradient calculation circuit. An attenuation function attenuates the calculated tap gradients by a programmable attenuation value.
    Type: Grant
    Filed: May 21, 2001
    Date of Patent: August 30, 2005
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Jonathan Darrel Coker, Richard Leo Galbraith, Eric James Tree
  • Method and apparatus for channel equalization with a digital FIR filter using a pseudo random sequence
    Publication number: 20030028833
    Abstract: A method and apparatus are provided for channel equalization with a digital finite impulse response (DFIR) filter using a pseudo random sequence. A readback signal of a pseudo random bit sequence is obtained. Samples are obtained from the readback signal of the pseudo random bit sequence. Tap gradients are calculated responsive to the obtained samples. The tap weights of the digital finite impulse response (FIR) filter are modified responsive to the calculated tap gradients. Dibit samples and error samples are obtained from the readback signal of the pseudo random bit sequence and applied to a tap gradients calculator. Tap gradients are calculated by a bitwise multiplier and accumulation tap gradient calculation circuit. An attenuation function attenuates the calculated tap gradients by a programmable attenuation value.
    Type: Application
    Filed: May 21, 2001
    Publication date: February 6, 2003
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Jonathan Darrel Coker, Richard Leo Galbraith, Eric James Tree