Patents by Inventor Fred T. Chu

Fred T. Chu 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).

  • Patent number: 7624314
    Abstract: A repeater-installed fault location mechanism conducts parametric measurements on a segment of wireline to which the repeater is connected, and adjusts taps of an echo cancellation operator in the repeater transceiver equipment, in accordance with the response of the wireline to an electrical stimulus imparted to the wireline segment. Information representative of the echo canceler tap coefficients is then transmitted over an overhead to a processor, to determine fault the location of a fault.
    Type: Grant
    Filed: December 19, 2006
    Date of Patent: November 24, 2009
    Assignee: Adtran, Inc.
    Inventor: Fred T. Chu
  • Patent number: 7174488
    Abstract: A repeater-installed fault location mechanism conducts parametric measurements on a segment of wireline to which the repeater is connected, and adjusts taps of an echo cancellation operator in the repeater transceiver equipment, in accordance with the response of the wireline to an electrical stimulus imparted to the wireline segment. Information representative of the echo canceler tap coefficients is then transmitted over an overhead to a processor, to determine fault the location of a fault.
    Type: Grant
    Filed: April 28, 2003
    Date of Patent: February 6, 2007
    Assignee: Adtran, Inc.
    Inventor: Fred T. Chu
  • Patent number: 7023963
    Abstract: A digital subscriber loop line card-installed mechanism conducts parametric measurements on the wireline to which the line card is connected, and adjusts taps of an echo cancellation operator in accordance with the response of the wireline to an electrical stimulus imparted to the wireline. The echo canceler tap coefficients are then processed to determine the location of a fault, such as a short circuit, open-circuit and the like, on the wireline. Fault information measurement data is then reported to a supervisory control location, which dispatches the appropriate technician to resolve the cause of the problem.
    Type: Grant
    Filed: March 31, 2003
    Date of Patent: April 4, 2006
    Assignee: Adtran, Inc.
    Inventors: Fred T. Chu, Dennis B. McMahan, James Ernest Owen, Bradley Dwayne Tidwell
  • Patent number: 6996230
    Abstract: An echo canceler for a fractionally spaced telecommunication receiver employs a signal estimator, which generates a fractionally spaced representation of a received information signal that has been subjected to Tomlinson preceding. The output of the signal estimator is differentially combined with fractionally spaced outputs of the echo canceller, so as to effectively remove the contribution of the received information signal from the echo cancellation update operation. As a result, the echo update signal will consist primarily of the residual echo and the noise from the wireline/loop. The error signal can be used at the fractional spacing rate to update all of the echo canceler coefficients, largely without interference from the much larger received information signal. This allows a higher echo canceler gain than that currently incorporated into HDSL2 echo canceler updates.
    Type: Grant
    Filed: June 13, 2003
    Date of Patent: February 7, 2006
    Assignee: Adtran, Inc.
    Inventors: Fred T. Chu, Michael D. Turner, Ayman K. Ghobrial
  • Patent number: 6975706
    Abstract: To locate an open fault along a telecommunication wireline pair, a prescribed frequency tone is coupled to the wireline pair by way of a center tap of the transformer through which a line card is coupled to a subscriber loop. The line card's analog front end conducts capacitance to ground measurements on the tip and ring segments of the wireline pair. From these measurements, sum and difference distance values of respective tip and ring conductor lengths are derived. The sum and difference distance values are then processed to calculate the distance to the fault.
    Type: Grant
    Filed: September 16, 2003
    Date of Patent: December 13, 2005
    Assignee: Adtran, Inc.
    Inventors: Daniel M. Joffe, Fred T. Chu