| 摘要 |
PURPOSE:To correct a dot disturbance occurring when a comb line filter is used and the rest of a color signal appearing much in one horizontal period, by adding a circuit, eliminating a color signal component remaining in a luminance signal component, and a trap circuit. CONSTITUTION:The output of adding circuit 79 forming the comb line filter is supplied to subtracting circuit 82 via delay line 81 and also supplied from delay line 81 to subtracting circuit 82 by way of BPF89 and switch circuit 92. This switch circuit 92, controlled by the circuit consisting of envelope detecting circuit 90, level comparing circuits 87 and 86, OR circuit 88, etc., is opened only in a period when a color signal component is included. Therefore, a luminance signal having a color component eliminated completely is obtained from adding circuit 83 supplied with the output of subtracting circuit 82 and the output of subtracting circuit 84 passed through LPF85. On the other hand, trap circuit 74 provided to subtracting circuit 72 outputting the color signal component can eliminate a color signal component derived much in one horizontal period. |
