Patents by Inventor Nancy D. Graves

Nancy D. Graves 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: 5034664
    Abstract: A parabola generator for geometric correction of a television raster, comprises: a resettable circuit for generating a repetitive ramp signal and a resettable integrator for generating a repetitive parabola signal from said repetitive ramp signal. A first resetting circuit initializes the ramp circuit at a frequency related to a scanning frequency. An auxiliary resetting circuit initializes the integrator prior to integrating each repetitive ramp. The auxiliary resetting circuit minimizes timing errors from variations of the ramp signal due to transient conditions. In one embodiment, the scanning period is a horizontal scanning period and the ramp and parabola circuits are reset at the end of each horizontal scanning interval. In this case, the first and auxiliary resetting circuits are responsive to horizontal retrace pulses, for example the leading edges of the horizontal retrace pulses. A further circuit modulates the periodically reset parabolic signal at a vertical scanning rate.
    Type: Grant
    Filed: April 27, 1990
    Date of Patent: July 23, 1991
    Assignee: Thomson Consumer Electronics, Inc.
    Inventors: Ronald E. Fernsler, Enrique Rodriguez-Cavazos, Nancy D. Graves
  • Patent number: 4972127
    Abstract: A circuit provides North-South pincushion correction and gullwing compensation in a raster display of a television apparatus. A correction circuit generates a generally parabolic, horizontal rate correction signal to correct for North-South pincushion distortion. A gullwing compensation circuit is coupled to the correction circuit and forms a feedback path therein for amplitude modifying the correction signal to further correct for gullwing distortion. The gullwing compensation circuit amplitude modifies the generally parabolic signal as a function of itself, achieving an equilibrium condition. A vertical deflection circuit drives a vertical deflection coil with the gullwing compensated correction signal. The correction circuit comprises a ramp waveform generator having a controllable current source generating a constant component of current for pincushion correction and a variable component of current responsive to the feedback signal for gullwing compensation.
    Type: Grant
    Filed: April 27, 1990
    Date of Patent: November 20, 1990
    Assignee: RCA Licensing Corporation
    Inventors: Enrique Rodriguez-Cavazos, Nancy D. Graves, Ronald E. Fernsler
  • Patent number: 4737853
    Abstract: A switched mode power supply for a video apparatus having an electrically isolated chassis incorporates a switching FET that has its conduction interval controlled by pulses of varying frequency. An inductor is connected between the FET and hot ground to provide a low impedance path for line conducted interference signals generated by the switching of the FET and to provide a sufficient impedance path to prevent damage to the FET due to current flow caused by a high voltage discharge, such as a lighting strike to the cold ground referenced antenna.
    Type: Grant
    Filed: April 30, 1987
    Date of Patent: April 12, 1988
    Assignee: RCA Corporation
    Inventors: Nancy D. Graves, Terry W. Bunton
  • Patent number: 4562508
    Abstract: A protection circuit for a video display apparatus causes shutdown to occur at substantially the same high voltage level for all fault conditions. The video display apparatus incorporates an SCR regulator and a high voltage transformer tuned to the third harmonic. To counter the effect of shutdown to occur at a higher voltage level for a shorted SCR fault than for other faults, the SCR anode control pulse is processed to provide a signal having different voltage levels for normal SCR operation and shorted SCR operation. The voltage level which occurs during a shorted SCR condition is selected to cause shutdown of the video display apparatus at substantially the same high voltage level as that for other fault conditions.
    Type: Grant
    Filed: May 10, 1984
    Date of Patent: December 31, 1985
    Assignee: RCA Corporation
    Inventors: John Chen, Chin Huang, Nancy D. Graves, James E. Hicks