| 摘要 |
PURPOSE:To obtain a low cost video display device in which a regulation can be satisfactory, and an interference on a raster can be reduced in each frequency at the time of receiving more than two horizontal frequency signals at a cathode ray tube. CONSTITUTION:When the horizontal frequency of an input signal is 15.7kHz, a switch 14 is switched to a fixed terminal (b) side, and the high voltage generating circuit of a cathode ray tube 1 is operated by the horizontal drive pulse of 15.7kHz outputted from a synchronizing separator circuit 16. Then, when the horizontal frequency of the input signal is 33.7kHz, the switch 14 is switched to a fixed terminal (a) side, the horizontal drive pulse of 33.7 KHz outputted from the synchronizing separator circuit 16 is 1/2 frequency-divided by a frequency-divider 15, waveform-shaped by a waveform shaping circuit 17, and added through the switch 14 to the high voltage generating circuit. Therefore, the high pressure regulation can not be changed, and the raster interference can be suppressed, regardless of the frequency of the input signal. |
