Patents by Inventor Hugh D. Stuart

Hugh D. Stuart 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).

  • Fail safe protection circuitry for a commerical microprocessor in encryption equipment
    Patent number: 4635223
    Abstract: In conjunction with a commercial microprocessor controlled by a program stored in a ROM, a second microprocessor, similar to the first microprocessor, is connected into the system so as to operate similar to the first microprocessor. A four-phase clock steps the first microprocessor, then steps the second microprocessor, then compares the instruction registers of the two microprocessors and causes the instruction to be executed if an exact comparison is detected. If an exact comparison is not detected, the instruction is not executed.
    Type: Grant
    Filed: June 18, 1986
    Date of Patent: January 6, 1987
    Assignee: Motorola, Inc.
    Inventors: Susan L. Boone, Hugh D. Stuart