| 摘要 |
PURPOSE:To obtain luminance signal having no chrominance signal by extracting a signal when the chrominance signal is mixed in the separated luminance signal and passing a composite video signal through an LPF to use the obtained luminance signal. CONSTITUTION:The composite video signal impressed to an input terminal 1 is separated to the luminance signal and the chrominance signal by a 1H delay circuit 2, a subtracter 3 and an adder 4, the chrominance signal is outputted to the output end of a BPF 5 and the luminance signal is outputted to the output end of a delay circuit 6. The composite video signal is impressed to the LPF 9, and the luminance signal having no chrominance signal included in the output. The output of the circuit 6 and the output of the LPF 9 are impressed to a switch circuit 12 and switched according to a pulse from a pulse generating circuit 11. When there is no vertical correlation in a picture, many chrominance signals are mixed in the luminance signal. This luminance signal is impressed to a BPF 10 to take out a chrominance signal component, it is impressed to the pulse generating circuit 11 and the circuit 11 generates the pulse. The circuit 12 passes the output of the LPF 9 according to this pulse and outputs from a terminal 8.
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