| 摘要 |
PURPOSE:To prevent that an object picture is displayed at the part where the background color picture should be essentially displayed by a false key signal due to the registration dislocation in the vertical direction by multiplying respectively the key signal which is delayed for one horizontal scanning period and the key signal which is not delayed, and making it into a key signal respectively with multiplication. CONSTITUTION:A key signal is supplied to a multiplier 6 after the signal is delayed for 1H at a 1H delaying circuit 5. A multiplier 6 is a circuit to multiply a 1H delaying key signal from a 1H delaying circuit 5 and a key signal from an input terminal 4, the output signal of the multiplier 6 is impressed to a switch circuit 3 as a switching signal, the low level period selects and outputs the input video signal of a terminal 3a, the high level period selects and outputs the input video signal of a terminal 3b, and in such a way, the switch circuit 3 is controlled by switching. Thus, the video signal of either of the first and second video signals is outputted to an output terminal 7.
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