| 摘要 |
PURPOSE:To always display a character such as a track number at the same location without longitudinal quivering by providing a monostable multivibrator circuit and counting a horizontal synchronizing signal in a composite synchronizing signal based on the time point of the end of its operation. CONSTITUTION:When an integration circuit 10 detects a vertical synchronizing signal V.Sync based on a composite synchronizing signal C.Sync in a 0.5H delay period, the signal is taken in a character generation IC9. On the other hand, the monostable multivibrator 13 is triggered on the leading edge of the timing t1 to turn on a transistor (TR) 14. Then even when the signal H.Sync is to be taken in the IC9 by inverting the signal C.Sync by the TR 11, the signal is given to the ground side by the TR 14 and only a pulse of nearly 8H is given. Then the monostable multivibrator 13 is turned off and the TR 14 is turned off, then the signal H.Sync is outputted sequentially to the IC 9. Then the signal H.Sync is counted, based on the operating end timing t2 of the monostable multivibrator 13 to decide the character display position, then the counting of a noise pulse A as 1H is avoided.
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