| 摘要 |
PURPOSE:To keep a high voltage output constant from a horizontal output circuit and a high voltage circuit even at no signal by discriminating the presence and absence of a synchronizing signal by a synchronizing signal discrimination circuit when no composite video signal exists and supplying a pseudo synchronizing signal from a synchronizing signal generating circuit by the output. CONSTITUTION:The emitter of a transistor 14 is connected to ground and a collector is connected to a +B power supply 17 via a load resistor 15 and connected to the input terminal of a synchronizing signal generating circuit 10 through a diode 10. When no horizontal synchronizing signal 11 is fed to a synchronizing signal discrimination circuit 9, a +B is supplied to the synchronizing signal generating circuit 10 to be in an operating state, and the pseudo synchronizing signal generated from the circuit 10 is fed to a phase detection circuit 7. Since the pseudo synchronizing signal and a comparison signal generated from a comparison signal generating circuit 6 make the phase comparison at the phase detection circuit 7, the correction voltage is almost kept constant and the horizontal oscillation frequency is not fluctuated and the stable high voltage is obtained.
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