| 摘要 |
PURPOSE:To obtain a highly accurate signal separating characteristic without adjustment by detecting a level difference between the color burst signal of a signal from an input terminal and a color burst signal a delayed with 1H and controlling the level of the 1H delayed signal so that the level difference comes to zero. CONSTITUTION:A part of a color video signal (a) supplied from an input terminal 1 is supplied to a level detecting device 14 and a part of a frequency component (b) outputted by a 1H delay line 5 is supplied through an AGC amplifier 11 to a level detecting device 15. Level detecting devices 14 and 15 extract a color burst signal in an input signal by a burst period signal (e), detects them by a peak and outputs direct current voltages (c) and (d). An error signal showing the difference between the two is formed by an error amplifier 16 and through a switch 17 and a holding circuit 18, the control signal showing the level of the error signal is obtained. The control signal is negatively fed back to the AGC amplifier 11 and controlled so that the error signal comes to zero. As the result, even when the variance exists for loss-in and loss-out at a 1H delay line, at an output terminal 9 the luminance signal, in which the cross talk is sufficiently removed, can be obtained.
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