Patents by Inventor Fa Foster Dai

Fa Foster Dai 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: 9391625
    Abstract: A digitally controlled oscillator (DCO) modulation apparatus and method provides a wideband phase-modulated signal output. An exemplary modulator circuit uses an oscillator in a phase-locked loop. The circuit receives a wrapped-phase input signal, unwraps the wrapped-phase input signal to generate an unwrapped-phase signal, and differentiates the unwrapped-phase signal. The wrapped-phase input signal and the differentiated unwrapped-phase signal are both injected into a feedback loop of the modulator circuit. The feedback loop may include a multi-modulus frequency divider with a frequency divisor that is temporarily incremented or decremented to cancel out abrupt phase jumps associated with the wrapped-phase to unwrapped-phase conversion.
    Type: Grant
    Filed: March 24, 2015
    Date of Patent: July 12, 2016
    Assignee: INNOPHASE INC.
    Inventors: Yang Xu, Fa Foster Dai, Dongyi Liao
  • Patent number: 9343809
    Abstract: An RF system comprising of outputs to an electronically scanning antenna for radiating electromagnetic energy; at least one waveform generator; two multiphase phase-locked loops integrated with the waveform generator, the phase locked loops operating to provide multiple shifted phases to a waveform. Optionally, the two multiphase phase-locked loops may each be divided down by a bank of frequency dividers to further increase the number of phase shifts. The phases generated from each multiphase phase-locked loops are selected with multiplexers then mixed together. These upper or lower sidebands are then mixed with the up converted waveform which results in a phase shift for the waveform associated with each antenna element.
    Type: Grant
    Filed: February 15, 2013
    Date of Patent: May 17, 2016
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Fa Foster Dai, Geoffrey Goldman
  • Patent number: 8138958
    Abstract: A time to digital converter (TDC) is able to be utilized for measuring a time interval between two signals with a very fine time resolution, which is defined as the difference in propagation delay per stage between two rings or chains of delay stages. The Vernier ring TDC, Vernier TDC with comparator matrix or Vernier ring TDCs with comparator matrix comprise two rings or chains of delay stages with slightly different propagation delays per stage and a plurality of comparators for comparing two signals propagation along two rings or chains and determining when the lag signal passes the lead signal. The lead and lag signal are initiated by two events and are each fed into a separate one the first stages of one of the specified rings or chains. The comparators are able to be organized in a comparator matrix in order to occupy less space and permit reuse.
    Type: Grant
    Filed: January 29, 2010
    Date of Patent: March 20, 2012
    Assignee: Auburn University
    Inventors: Fa Foster Dai, Jianjun Yu
  • Publication number: 20100283653
    Abstract: A time to digital converter (TDC) is able to be utilized for measuring a time interval between two signals with a very fine time resolution, which is defined as the difference in propagation delay per stage between two rings or chains of delay stages. The Vernier ring TDC, Vernier TDC with comparator matrix or Vernier ring TDCs with comparator matrix comprise two rings or chains of delay stages with slightly different propagation delays per stage and a plurality of comparators for comparing two signals propagation along two rings or chains and determining when the lag signal passes the lead signal. The lead and lag signal are initiated by two events and are each fed into a separate one the first stages of one of the specified rings or chains. The comparators are able to be organized in a comparator matrix in order to occupy less space and permit reuse.
    Type: Application
    Filed: January 29, 2010
    Publication date: November 11, 2010
    Applicant: Auburn University
    Inventors: Fa Foster Dai, Jianjun Yu