PURPOSE: To eliminate erroneous operation for ghost elimination through simple constitution, by stopping weighting adjustment when the peak value of a sink- pitch directional noise before the leading edge of a vertical synchronizing signal exceeds the mean value of the signal at succeeding parts.
CONSTITUTION: A video signal obtained at an input terminal 31 is supplied through a synchronism separating circuit 32 and a vertical synchronism separating circuit 33 to a masking pulse generating circuit 34, whose output is applied to monostable multivibrators 35 and 37 to generate control signals for switches 51 and 62. On the other hand, the video signal is supplied from the switches 51 and 62 to low-pass filters 53 and 63 through a current mirror circuit 50. The switches 51 and 62 are turned on at parts before and after the leading edge of a vertical synchronizing signal. For this purpose, the peak value of a noise before the leading edge in a sink-chip direction is compared at a part 65 with the mean value of the signal at succeeding parts, and a detection output obtained at a terminal 66 when the peak value exceeds the mean value is used to stop the weighting adjustment of a transversal filter which is not shown in the figure, eliminating erroneous operation for ghost elimination.
KURIKI CHIYOUEI
SAITOU JIYUNYA
