| 摘要 |
PURPOSE:To obtain synchronizing accuracy equivalent to the increase of the oscillating frequency of an original signal by generating a scanning start signal and selecting a signal synchronizing or nearly synchronizing with a scanning start signal among plural delay original signals as a scanning synchronizing signal. CONSTITUTION:The titled circuit is provided with an original signal generating circuit 1 as the generating source of a scanning synchronizing signal SYNC, a scanning start signal generating circuit 7, a delay circuit 3 generating plural delay original signals f1-f10 and a selection circuit 5. The selection circuit 5 has plural flip-flops provided to hold the state of the delay original signals f1-f10 for a prescribed period with the scanning start signal SOS caused and a priority selection circuit discriminating whether which of the signals f1-f10 is skynchronized or nearly synchronized with the signal SOS depending of the state of the signals f1-f10 held in the flip-flops. Thus, the synchronizing accuracy equivalent to the setting of the oscillating frequency of the original signal higher is obtained without increasing the oscillating frequency of the original signal higher than the frequency of the scanning synchronizing signal SYNC. |
