| 摘要 |
PURPOSE:To print out an image of a television picture correctly without being affected by noise even in receiving under weak electric field by applying automatic frequency control to a horizontal synchronizing signal. CONSTITUTION:Horizontal and vertical synchronizing signals s1, s2 are extracted from a composite video signal v1 given from a television receiving set by a synchronizing separator circuit 7 and become a video signal v2 and inputted and an A/D converter, and a gradation density signal d1 is outputted. When noises are superposed on the signal v1 due to receiving under a weak electric field, the noise is included also in s1, s2. So, AFC is applied to s1 by an AFC circuit 8. Accordingly, a writing controlling circuit 3 makes address counting by using s1 to which AFC is applied. Therefore, the signal d1 is written in normal address in the image memory 2 as in the case of normal state which is not receiving under a weak electric field. Thus, a normal picture can be printed out without being affected by the noise.
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