Patents by Inventor Phillip J. Hunter

Phillip J. Hunter 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).

  • Active filter having series resonant active filter terminated by parallel resonant active filter
    Patent number: 4686486
    Abstract: A fourth (or higher) order filter has a series resonant section terminated by a parallel resonant section, both based on frequency dependent negative resistance (FDNR). The FDNR, resistance and capacitance (representing damping) of the series section are provided by a capacitive potential divider (C41,C42) connected between low impedance input (A) to the filter and an intermediate terminal forming the input of a unity-gain amplifier (A4) whose output is connected via a resistance (R4O) to the tapping point of the divider; the intermediate terminal is connected via a second resistance (R1) to the parallel section.
    Type: Grant
    Filed: July 5, 1985
    Date of Patent: August 11, 1987
    Assignee: British Telecommunications public limited company
    Inventors: Alan J. Greaves, Phillip J. Hunter