Patents by Inventor David E. Zimmerman

David E. Zimmerman 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: 5075580
    Abstract: A circuit for converting ECL logic level signals to CMOS logic level signals comprises a differential amplifier defining first and second current paths that are connected to a negative reference potential level. When the ECL input signal is logical zero, the first current path is non-conductive and the second path is conductive, and vice versa when the input signal is logical one. A first transistor has its base connected to the first current path, its emitter connected to a positive reference potential level, and its collector connected to the second current path. A second transistor has its base connected to the second current path, its emitter connected to the output terminal, and its collector connected to a ground reference potential level. A pull-up resistor is connected between the collector and emitter of the first transistor.
    Type: Grant
    Filed: September 6, 1990
    Date of Patent: December 24, 1991
    Assignee: NVision, Inc.
    Inventors: Birney D. Dayton, David E. Zimmerman
  • Patent number: 4757508
    Abstract: A tracking modulation limiter for laser diodes tracks from the output of a laser diode the maximum forward current. The maximum forward current is multiplied by a factor less than one to generate a control current representative of the maximum negative modulation for the laser diode. The control current is modulated by an input modulation signal and combined with the maximum forward current to drive the laser diode so that the drive current does not fall below threshold.
    Type: Grant
    Filed: December 7, 1987
    Date of Patent: July 12, 1988
    Assignee: The Grass Valley Group, Inc.
    Inventor: David E. Zimmerman
  • Patent number: D515444
    Type: Grant
    Filed: January 13, 2005
    Date of Patent: February 21, 2006
    Assignee: ZTS, Inc.
    Inventors: David E. Zimmerman, Philip D. Zimmerman
  • Patent number: D569285
    Type: Grant
    Filed: May 8, 2007
    Date of Patent: May 20, 2008
    Assignee: ZTS, Inc.
    Inventors: David E. Zimmerman, Philip D. Zimmerman
  • Patent number: D611851
    Type: Grant
    Filed: July 9, 2009
    Date of Patent: March 16, 2010
    Assignee: ZTS, Inc.
    Inventors: David E. Zimmerman, Philip D. Zimmerman