Patents by Inventor Kashif Sheikh

Kashif Sheikh 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).

  • Fractional-N frequency synthesizer having reduced fractional switching noise
    Patent number: 8531217
    Abstract: A fractional-N frequency synthesizer having reduced fractional switching noise and spurious signals is provided. The synthesizer includes a voltage controlled oscillator for providing an output signal. A fractional-N divider is responsive to the voltage controlled oscillator for providing a divided output signal having fractional switching noise. A band pass filter is responsive to the fractional-N divider for reducing the fractional switching noise and non-linearities that result in spurious signals. A phase detector is responsive to a reference signal and the band pass filter for providing a control signal representative of the phase difference between the reference signal and the signal from the band pass filter. A loop filter is responsive to the phase detector for filtering the control signal to control the voltage controlled oscillator, the output of the loop filter having reduced fractional switching noise and spurious signals.
    Type: Grant
    Filed: April 9, 2010
    Date of Patent: September 10, 2013
    Assignee: Hittite Microwave Corporation
    Inventors: Mark M. Cloutier, Kashif Sheikh
  • Fractional-N frequency synthesizer having reduced fractional switching noise
    Publication number: 20100264965
    Abstract: A fractional-N frequency synthesizer having reduced fractional switching noise and spurious signals is provided. The synthesizer includes a voltage controlled oscillator for providing an output signal. A fractional-N divider is responsive to the voltage controlled oscillator for providing a divided output signal having fractional switching noise. A band pass filter is responsive to the fractional-N divider for reducing the fractional switching noise and non-linearities that result in spurious signals. A phase detector is responsive to a reference signal and the band pass filter for providing a control signal representative of the phase difference between the reference signal and the signal from the band pass filter. A loop filter is responsive to the phase detector for filtering the control signal to control the voltage controlled oscillator, the output of the loop filter having reduced fractional switching noise and spurious signals.
    Type: Application
    Filed: April 9, 2010
    Publication date: October 21, 2010
    Inventors: Mark M. Cloutier, Kashif Sheikh