Apparatus for improving the contrast focusing of a tv picture by aperture correcting the video tv signal on both sides

Claim 1

In a circuit arrangement for increasing the sharpness of the horizontal and vertical contours in a television picture by aperture correcting the video signal, the combination comprising input means for a television signal, a first delay means connected to said input means for delaying the television signal by one line period, second delay means coupled to said first delay means for delaying said television signal by a further line period, adding means for combining said undelayed and twice delayed television signals into a sum signal, means for reversing the polarity of said sum signal and reducing the amplitude thereof to half, second adding means for combining the output of said polarity reversing means with said once delayed television signal for obtaining said vertical aperture correcting signal, means for reversing the polarity of said once-delayed signal, means for compensating said once delayed television signal for transit time, third adding means for combining the output of the last-mentioned polarity reversing means and said compensating means for obtaining said horizontal aperture correcting signal, fourth adding means for combining the horizontal and vertical aperture correcting signals into a single correcting signal, and fifth adding means for combining the single correcting signal with the once-delayed television signal.