| 摘要 |
PURPOSE:To write on a picture memory irrespective of the cycle of a synchronizing signal, by separating the synchronization signal component from the compound video signal, and variably controlling the writing cycle onto the picture memory according to the cycle of the synchronization signal. CONSTITUTION:Compound video signal outputted from an outside video signal outputting device 1 contains a video signal and a synchronizing signal whose signal component is separated by a separator 2, and further separated into a horizontal synchronization signal and a vertical synchronization signal by a pulse width discriminator 3. These signals are then inputted to frequency meters 4, 5 and the frequency of each signal is detected. According to the frequency thus detected, a timing control 6 automatically changes and controls the cycle of a write signal for a picture memory 7 and the cycle of a sampling pulse for an A/D converter 8. |
