Patents by Inventor Anthony Francis Keller

Anthony Francis Keller 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).

  • Crystal oscillator temperature compensating circuit
    Patent number: 3970966
    Abstract: A circuit for generating a temperature varying control voltage which is applied to a varactor diode to temperature compensate a crystal oscillator is disclosed. The circuit produces a substantially linear voltage versus temperature variation, including a point of inflection, in a middle temperature range, and a substantially non-linear voltage versus temperature variation in hot and cold temperature ranges. The control voltage versus temperature characteristic also undergoes a change in slope polarity in both the hot and cold temperature ranges. The temperature compensating circuit has a middle range circuit for independently creating the substantially linear variation in the middle temperature range, a cold range circuit operative below a predetermined temperature for creating the desired variation in the cold temperature range, and a hot temperature circuit operative above a predetermined temperature for creating the desired temperature variation in the hot temperature range.
    Type: Grant
    Filed: April 25, 1975
    Date of Patent: July 20, 1976
    Assignee: Motorola, Inc.
    Inventors: Anthony Francis Keller, Dennis Fisher Marvin