Patents by Inventor John D. Foell

John D. Foell 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).

  • Automatic sweep-to-lock circuit for a phase-locked loop
    Patent number: 5091702
    Abstract: A method for a phase-locked loop, which circuit includes, in a preferred embodiment, a resistor to unbalance phase detector outputs to an operational amplifier to cause the voltage output of the operational amplifier to sweep and thus cause the frequency output of a voltage controlled oscillator to sweep. Simple circuitry detects correct lock and terminates sweeping; or, if lock is not achieved, causes the output of the operational amplifier to remain at a low level until the operational amplifier is reset and then permits resweep. Very little auxiliary circuitry is required.
    Type: Grant
    Filed: December 21, 1990
    Date of Patent: February 25, 1992
    Assignee: Magnavox Government and Industrial Electronics Company
    Inventor: John D. Foell