Patents by Inventor John D. Schilling

John D. Schilling 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: 4814887
    Abstract: An automatic frequency control tracks a television signal before and after a period of interruption. The automatic frequency control comprises a voltage controlled feedback loop including a voltage controlled local oscillator and a mixer for mixing the output of the oscillator with the TV signal. The output of the mixer is filtered to remove unwanted components of the mixed signal and to equalize sidebands of the television signal. The output of the filter is supplied to a detector which is tuned to a component of the television signal, and produces a voltage corresponding to the frequency of the component. The output of the detector is supplied to the voltage control input of the local oscillator to track the television signal component. Circuitry automatically senses the absence of the TV signal component from the mixer, and automatically applies a reference voltage to the voltage control input of the oscillator when the TV signal component is absent.
    Type: Grant
    Filed: May 23, 1988
    Date of Patent: March 21, 1989
    Assignee: General Instrument Corporation
    Inventors: Daniel J. Marz, John D. Schilling