GB650836A - Improvements in and relating to cathode ray tube circuits - Google Patents

Abstract

650,836. Cathode-ray tubes. GENERAL ELECTRIC CO., Ltd., and LEVY, M. M. Dec. 9, 1947, No. 32469. [Class 39 (i)] In a cathode-ray tube circuit having an electrode adapted to collect electrons at a reduced rate when the beam is inoperative, a voltage dependent upon the variation of the electron current to the electrode is applied to an intensity control electrode whereby the electron current in the beam is reduced when it is inoperative. In a multi-channel pulse signalling system, the beam is deflected between a conical electrode 14 and a series of deflecting plates S, each of which is connected to a signal channel so that the beam is radially deflected by each signal across a corresponding inclined slot in the plate 11 to produce a time-modulated electron pulse at the collector 12. The beam current is adapted to be increased when it passes through a slot in the plate 11 by suitable back-coupling between the collector 12, which produces negative pulses, and the control grid or cathode through the amplifier 13. The modulated signals are also fed directly or through the amplifier 13, or a part thereof, to the aerial 16 through the amplifier and radio-frequency modulator 15. The feed-back might be drawn from the plate 11 or from a further electrode adapted to collect secondary electrons from the plate 11, electrode 12 or the glass wall or a mica plate. The slotted plate 11 may be replaced by inclined wires or strips. A wide-band amplifier 13 may be followed by a class C amplifying valve, the anode of which is connected to a tuned circuit so that a suitable voltage peak may be applied to the control grid of the cathode-ray tube.