Patents by Inventor William Ngai

William Ngai 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: 8208530
    Abstract: An apparatus and method for correcting IQ imbalance are presented. An exemplary receiver for processing I and Q signals from a tuner includes: a non-decision directed (NDD) imbalance canceller coupled to receive the I and Q signals, and a decision directed (DD) imbalance canceller coupled to the non-decision directed imbalance canceller. The DD imbalance canceller converges after the NDD imbalance canceller converges, so as to correct IQ imbalances in the receiver. An exemplary method for processing I and Q signals from a tuner includes: (a) converging a NDD imbalance canceller to correct a majority of IQ imbalances, and (b) subsequently converging a DD imbalance canceller to correct a remainder of IQ imbalances not corrected in step (a). The apparatus and method correct frequency-dependent and frequency-independent IQ imbalances.
    Type: Grant
    Filed: January 19, 2006
    Date of Patent: June 26, 2012
    Assignee: Broadcom Corporation
    Inventors: Loke Tan, Hanli Zou, William Ngai
  • Publication number: 20060203901
    Abstract: An apparatus and method for correcting IQ imbalance are presented. An exemplary receiver for processing I and Q signals from a tuner includes: a non-decision directed (NDD) imbalance canceller coupled to receive the I and Q signals, and a decision directed (DD) imbalance canceller coupled to the non-decision directed imbalance canceller. The DD imbalance canceller converges after the NDD imbalance canceller converges, so as to correct IQ imbalances in the receiver. An exemplary method for processing I and Q signals from a tuner includes: (a) converging a NDD imbalance canceller to correct a majority of IQ imbalances, and (b) subsequently converging a DD imbalance canceller to correct a remainder of IQ imbalances not corrected in step (a). The apparatus and method correct frequency-dependent and frequency-independent IQ imbalances.
    Type: Application
    Filed: January 19, 2006
    Publication date: September 14, 2006
    Applicant: Broadcom Corporation
    Inventors: Loke Tan, Hanli Zou, William Ngai
  • Patent number: 7050516
    Abstract: A system for periodic noise avoidance including a timing discriminator receiving an input signal from a communications channel. The input signal includes data packets and empty slots with periodic noise. The timing discriminator outputs a first error measurement of periodic noise width and a second error measurement of periodic noise position. A first loop filter inputs the first error measurement and outputs a width of the empty slots. A second loop filter inputs the second error measurement and outputs a frequency of the periodic noise. An oscillator inputs the width of the empty slots and the frequency, and outputs an empty slot waveform to the timing discriminator.
    Type: Grant
    Filed: March 20, 2003
    Date of Patent: May 23, 2006
    Assignee: Broadcom Corporation
    Inventors: Bruce J. Currivan, Thomas J. Kolze, Daniel H. Howard, Nabil Yousef, William Ngai
  • Publication number: 20040184571
    Abstract: A system for periodic noise avoidance including a timing discriminator receiving an input signal from a communications channel. The input signal includes data packets and empty slots with periodic noise. The timing discriminator outputs a first error measurement of periodic noise width and a second error measurement of periodic noise position. A first loop filter inputs the first error measurement and outputs a width of the empty slots. A second loop filter inputs the second error measurement and outputs a frequency of the periodic noise. An oscillator inputs the width of the empty slots and the frequency, and outputs an empty slot waveform to the timing discriminator.
    Type: Application
    Filed: March 20, 2003
    Publication date: September 23, 2004
    Applicant: Broadcom Corporation
    Inventors: Bruce J. Currivan, Thomas J. Kolze, Daniel H. Howard, Nabil Yousef, William Ngai