| 摘要 |
PURPOSE:To save memory and simplify peripheral circuits by not writing a part of data in vertical blanking period of video signals in a field memory. CONSTITUTION:Video signals Sv converted to digital signals by an A/D convertor 5 are supplied to memories 16a and 16b for each 1V through a switching circuit 16c and written. At the same time, the video signal written in 1V of just before from the memories 16a and 16b is read continuously twice at period of 1/2V and this is obtained through a switching circuit 16d. Writing and reading in the memories 16a and 16b are controlled by a memory controlling circuit 17. Data of 4-5 horizontal period of vertical blanking period of the video signals Sv are not written in the memories 16a and 16b. Signals CW3 and CW6 of frequency three to six times that of color burst signal Ssc are supplied to the memory controlling circuit 17, and at the same time, vertical synchronizing signal Pv and a signal Pv2 having frequency twice that of the signal Pv is supplied. |
