| 摘要 |
647,767. Television receivers. PHILIPS LAMPS, Ltd. Jan. 10, 1947, No. 941. Convention date, Jan. 15, 1946. [Class 40 (iii)] [Also in Group XL (c)] In a television receiver arrangement operated by line synchronizing impulses and a frame pulse which is interrupted, the frame saw-tooth generator is operated by one of the interruption pulses and is not affected by the other interruptions. The complete television signal from which the picture components have been eliminated is fed to a circuit comprising a condenser C1 and a resistance R1 in series with a battery E so that solely the pulses A, B ... are fed to the first control grid g<SP>1</SP> of the valve 3. The first impulse A makes the valve conductive and produces at resistance R4 a pulse for operating the frame saw-tooth generator. Current flows in the circuit of the screen grid g<SP>2</SP> and effects a voltage drop across a high resistance R3 shunted by a condenser C3, the circuit R3, C3 having a time constant such that condenser C3 is rapidly discharged and slowly charged through the resistance R3 when the valve 3 is cut off at the end of a pulse. The voltage at the grid g<SP>2</SP> decreases in stepwise form, as indicated by Fig. 3b, and is applied via condenser C2 and resistance R2, having a relatively long time constant, to a second control grid g3 so that current flow in the anode circuit of the tube 3 is cut off except for the first impulse. The screen grid g<SP>2</SP> is preferably connected to a second screen grid located, as shown, between the second control grid g<SP>3</SP> and the anode. The Specification as open to inspection under Sect. 91 states that by suitable alteration of the time constant of the circuit R1, C1 the second or a subsequent interrupting pulse may be utilized to operate the valve 3 and effect the operation of the saw-tooth generator. The single valve 3 with its two separate control grids may be replaced by two separate valves This subject-matter does not appear in the Specification as accepted. |
