| 摘要 |
1,216,996. Sawtooth circuits. RCA CORPORATION. 29 Feb., 1968 [21 March, 1967], No. 9858/68. Heading H3P. A vertical deflection circuit for a television receiver comprises a capacitor 46 for developing a sawtooth voltage waveform which is fed to the control electrode of an amplifying device 22, the output of which is coupled at V, V<SP>1</SP> to deflection windings. A further capacitor 28 is charged by a diode 32 during the flyback period and discharged during the forward stroke via resistors 38, 40 connected to a stabilized voltage source. Part of the waveform across capacitor 28 is coupled via resistor 42 to the grid so that the grid bias and hence the trace linearity is adjustable by resistor 30. The stabilized supply is preferably provided by a VDR 36 and is adjustable by resistor 38 (height control). The circuit is preferably made self-oscillatory by feedback from the secondary of the output transformer 24 via an integrator 56 to the base of transistor 50 which discharges the time base capacitor 46 at the end of each sweep. A hold control 60 is provided. The circuit is synchronized by pulses fed to the grid of valve 22 or the base of transistor 50. Modifications.-Transistor 50 may be replaced by a vacuum triode. Resistor 23 may be omitted. |
