Patents by Inventor Nigel K. Webb

Nigel K. Webb 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: 5038120
    Abstract: A fractional-N type frequency synthesizer has a voltage controlled oscillator controlled in a phase-locked loop by a divide by N divider and a phase comparator responsive to the divided frequency and to a reference frequency Fr. An accumulator is responsive to the desired fractional part of the N and is clocked by Fr to produce carry signals for producing the required periodic variations in N. A second accumulator produces periodic equal and opposite further variations in N to reduce the magnitude of the error waveform which would be given to the phase-detector output by the variations in n caused by the first accumulator. A digital to analog converter and a differentiating circuit produce a jitter correction signal for reducing residual jitter. A coherent detector detects for the presence of any residual jitter at the control input of the VCO and resulting from the fractional-N control circuit.
    Type: Grant
    Filed: March 1, 1990
    Date of Patent: August 6, 1991
    Assignee: Racal-Dana Instruments Limited
    Inventors: Mark A. Wheatley, Leslie A. Lepper, Nigel K. Webb