Television camera having a beam current control circuit
AssigneeU.S. Philips Corporation
InventorHendrik Blom
Life of this patent
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Abstract
A television camera comprising a control stage and a setting stage for the beam current control of an electron beam in a pick-up tube. Via a video frequency picture signal amplifier suitable for processing the picture signal generated by the pick-up tube, the picture signal generated by the pick-up tube is superimposed via a coupling capacitor as a control voltage on the setting voltage for the control electrode of the pick-up tube. A stable beam current control without oscillations is the result.
Claims4
A television camera comprising at least one pick-up tube and a control circuit for the intensity control of an electron beam present in the pick-up tube, the electron beam being generated by an electron gun comprising at least a cathode and a control electrode, an output, carrying a picture signal, of the pick-up tube being connected for beam current intensity control to a control input of the control circuit, an output of which, carrying a control signal, being connected to the control electrode in the pick-up tube, the control circuit comprising a setting stage, for an adjustment of the beam current intensity, and a control stage for an automatic control thereof, wherein the control stage comprises, provided between the control input of the control circuit and the output of the control stage, a video frequency picture signal amplifier suitable for processing the picture signal generated by the pick-up tube, said amplifier having an amplitude limiter therein, the output of the control stage being connected through a coupling capacitor to the output of the setting stage and at the same time to the control electrode of the pick-up tube.
Dependencies are inferred from the claim text.