Dynamic beam current control
AssigneeNorth American Philips Corporation
InventorJohann Safar
Life of this patent
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Abstract
A dynamic beam current control circuit for a television camera tube features a threshold circuit so that the correction is effected only for large light intensities impinging on the television camera tube. It also features a non-linear circuit which has a characteristic which is in the inverse of the control electrode voltage versus beam current characteristic of the camera tube. This prevents a ghost effect from showing in the display picture.
Claims5
A dynamic beam current control circuit for use with a television camera tube having a target and an electrode associated therewith, and a control electrode for controlling the beam current which flows in the tube, said circuit comprising a threshold detector having input means for receiving a signal from said target electrode and an output, and a non-linear processing circuit coupled to said output of said threshold detector for supplying a control signal to said control electrode, characterized in that said non-linear processing circuit has an input-to-output characteristic that is the inverse of the control electrode voltage versus the beam current characteristic of said camera tube.
Dependencies are inferred from the claim text.