Patents by Inventor M. Kathryn Christensen

M. Kathryn Christensen 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).

  • Indirectly sensed signal processing in active periodic acoustic noise cancellation
    Patent number: 5502770
    Abstract: The system employing and the processing of, an indirectly sensed signal representative of a periodic noise acoustic wave into an input signal for a noise cancelling system where the indirectly sensed signal is converted into a pulse signal per period that carries fundamental and harmonic frequency information of the periodic noise. A tachometer type RPM signal is processed in a counter circuit controlled by a logic circuit to produce a signal of one pulse per revolution with a controlled duration, the pulse amplitude is adjusted, the pulses are low pass filtered and any D.C. is blocked from the noise cancelling system input.
    Type: Grant
    Filed: November 29, 1993
    Date of Patent: March 26, 1996
    Assignee: Caterpillar Inc.
    Inventors: Sen M. Kuo, Minjiang Ji, M. Kathryn Christensen, Robert A. Herold
  • Noise suppression enclosure for an engine
    Patent number: 5467747
    Abstract: Most existing noise reduction enclosures used with engines and engine driven equipment have failed to meet the reduced noise emission requirements of today and of the future. A few of the present enclosures meet the reduced noise emission requirements of today and of the future but are extremely expensive to purchase and are large bulky structures. The subject enclosure (10) is reasonably priced and provides an enclosure which is effective in reducing the noise emitted therefrom. The enclosure (10) includes a housing (32) having a generally rectangular configuration and being divided into an engine portion (56) defining an engine compartment (57) and a duct portion (54). The outlet ducts (88) having a length greater than the inlet ducts (84). To further enhance the noise reduction of the enclosure (10) a plurality of dynastic hardware is attached to the housing (32).
    Type: Grant
    Filed: January 10, 1994
    Date of Patent: November 21, 1995
    Assignee: Caterpillar Inc.
    Inventors: Everett G. Brandt, M. Kathryn Christensen, W. Charles Sahm
  • Noise suppression enclosure for an engine
    Patent number: 5297517
    Abstract: Most existing noise reduction enclosures used with engines and engine driven equipment have failed to meet the reduced noise emission requirements of today and of the future. A few of the present enclosures meet the reduced noise emission requirements of today and of the future but are extremely expensive to purchase and are large bulky structures. The subject enclosure (10) is reasonably priced and provides an enclosure which is effective in reducing the noise emitted therefrom. The enclosure (10) includes a housing (32) having a generally rectangular configuration and being divided into an engine portion (56) defining an engine compartment (57) and a duct portion (54). The outlet ducts (88) having a length greater than the inlet ducts (84). To further enhance the noise reduction of the enclosure (10) a plurality of dynastic hardware is attached to the housing (32).
    Type: Grant
    Filed: August 19, 1991
    Date of Patent: March 29, 1994
    Assignee: Caterpillar Inc.
    Inventors: Everett G. Brandt, M. Kathryn Christensen, W. Charles Sahm