schaltungsanordnung to better leistungsmaessigen utilization of endroehre a zeilenablenkschaltung for a fernsehwiedergaberoehre

摘要

857,998. Valve sawtooth generator circuits. PHILIPS ELECTRICAL INDUSTRIES Ltd. Sept. 2, 1959, No. 29956/59. Class 40(6). In a line time base generator of the type in which a driver valve feeds deflection coils through an output transformer, a capacitor is connected in series with the deflection coils and the transformer and the voltage across the capacitor is added to the D.C. voltage applied to the screen grid of the driver valve so that the screen voltage is higher at the ends of the scan than at the centre. In Fig. 2 the driver V1 feeds deflection coils Ld through an auto transformer, the circuit being provided with a damping diode V2 a boost capacitor Cb and a capacitor Cs in series with the deflection coils. A voltage is developed across the latter capacitor of parabolic form so that the waveform produced by the deflection coils is S-shaped to compensate for the flatness of the face of the tube. The capacitor voltage is also added to the screen grid voltage for the driver valve so that the screen voltage and dissipation is lowered during the middle part of the scan. The screens current flows through the upper part of the auto transformer winding and the deflection coils thus reducing the flux in the core and providing a field in the deflection coils which helps to centre the picture. The anode of the diode of V2 could alternatively be connected to the lower terminal of the capacitor Cs. It is stated that the flyback could intrude into the first part of the television picture signal period and the sawtooth produced could be shaped such that the first part of the picture is folded over, to reduce the load on the driver valve.