| 摘要 |
PURPOSE:To inform generation of an abnormality due to the turn off of a line by outputting a static picture when an input signal turn-off is within a constant time and changing over the static picture to a black bursting signal when the input signal turn-off is the constant time or above. CONSTITUTION:An input video signal, after it is converted to a digital signal by an A/D converter, is stored into a frame memory 4. When the turn-off of the input video signal is within a constant period, a line turn-off compensating circuit 24 is operated, and a static picture is formed from the video signal inputted before the turn-off of the line. The formed static picture signal is outputted through a chroma inverter 11 and a DA converter 10 to a video output terminal. On the other hand, when the turn-off time of the input signal is continued longer than the constant period, a line turn-off alarm circuit 25 is formed, a blanking adding device 8 is operated and the static picture is changed over to a blanking signal. Thus, the abnormality generation due to the line turn-off can be informed.
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