| 摘要 |
PURPOSE:To stabilize vertical synchronism regardless of the level of a noise, by using a peak clamping type vertical synchronizing and separating circuit for a vertical deflecting circuit which uses a vertical and a horizontal oscillating circuit, a frequency dividing circuit, a switching circuit, etc. CONSTITUTION:A vertical synchronizing device is equipped with a vertical oscillator 4 which oscillates synchronizing with a vertical synchronizing signal separated from a TV signal, a horizontal oscillator 8 which oscillates at a frequency as high as a horizontal frequency, a frequency dividing circuit 9 which divides the frequency of its horizontal oscillation output up to a vertical frequency, and a switching circuit 10 which switches and switches and outputs the output of the vertical oscillating circuit 4 and that of the frequency dividing circuit 9 to a vertical deflecting circuit 6. Then, a peak clamping type vertical synchronizing and separating circuit 14 separates the vertical synchronizing signal and when its frequency is lower than a prescribed one, that is detected through a frequency discriminating circuit 13 to supply the output of the frequency dividing circuit 9 from the switching circuit 10. Thus, when a noise level is high, the noise is inverted by an inverter circuit 1 and when low, the vertical synchronizing signal is detected, stabilizing vertical synchronism. |
