2-line YC separation device

A 2-line YC separation device for use with a composite input video signal, said device comprising:

• a first delay circuit for delaying the composite input video signal;
• a first band-pass filter for filtering said composite input video signal;
• a second-band pass filter for filtering an output signal of said first delay circuit;
• a C signal detector coupled to said first and said second band-pass filters for detecting a voltage of a chrominance signal;
• a C-correlation detector coupled to said C signal detector;
• a difference detector to detect a Y signal voltage from the difference in said composite input video signal and the output signal of said first delay circuit;
• a YL difference detector for detecting an amplitude of an output signal of said difference detector after removing a frequency component in a frequency band of the chrominance signal;
• a YL-correlation detector for detecting a line correlation responsive to an output signal of said YL difference detector;
• a second delay circuit for delaying an output signal of said C-correlation detector;
• a third delay circuit for delaying an output signal of said YL-correlation detector;
• a first switch determining circuit coupled to i) said YL-correlation detector, ii) said C-correlation detector, iii) said second delay circuit and iv) said third delay circuit;
• a second switch determining circuit coupled to i) said YL-correlation detector, ii) said C-correlation detector, iii)said second delay circuit and, iv) said third delay circuit;
• a first inverter for inverting the output signal of said first band-pass filter;
• a second inverter for inverting the output signal of said second bandpass filter;
• a calculator for generating a mean value based on the output signals of said first and second band-pass filters;
• a first switch circuit which selectively outputs one of an output signal of i) said calculator, ii) said second inverter, and iii) said second band-pass filter responsive to an output signal of said first switch determining circuit;
• a second switch circuit which selectively outputs one of the output signals of said calculator and said second band-pass filter responsive to an output signal of said second switch determining circuit;
• a 3-line-comb operational circuit coupled to said first inverter, said first switch circuit, and said second switch circuit;
• a subtractor coupled to said first delay circuit and said 3-line-comb operational circuit;
• and
• a filter for filtering an output signal of said 3-line-comb operational circuit.

A 2-line YC separation device for use with a composite input video signal, said device comprising:

• a first delay circuit for delaying the composite input video signal for at least one horizontal scanning period;
• a first band-pass filter which receives said composite input video signal;
• a second-band pass filter coupled to said first delay circuit;
• a C signal detector coupled to said first and said second band-pass filters, for detecting a voltage of a chrominance signal;
• a C-correlation detector coupled to said C signal detector;
• a difference detector to detect a Y signal voltage from a difference in said composite input video signal and an output signal of said first delay circuit;
• a YL difference detector for detecting an amplitude of an output signal of said difference detector after removing a frequency component in a frequency band of the chrominance signal;
• a multiburst detector coupled to said YL difference detector, said multiburst detector selectively passing an output signal of said YL difference detector to said C-correlation detector;
• a Y-correlation detector coupled to said first and second band-pass filters;
• a second delay circuit for delaying an output signal of said C-correlation detector;
• a third delay circuit for delaying an output signal of said Y-correlation detector;
• a first switch determining circuit coupled to i) said Y-correlation detector, ii) said C-correlation detector, iii) said second delay circuit and iv) said third delay circuit;
• a second switch determining circuit coupled to i) said Y-correlation detector, ii) said C-correlation detector, iii)said second delay circuit and, iv) said third delay circuit;
• a first inverter for inverting an output signal of said first band-pass filter;
• a second inverter for inverting an output signal of said second band-pass filter;
• a calculator for generating a mean value based on the output signals of said first and second band-pass filters;
• a first switch circuit which selectively outputs one of the output signals of i) said calculator, ii) said second inverter, and iii) said second band-pass filter responsive to an output signal of said first switch determining circuit;
• a second switch circuit which selectively outputs one of the output signals of said calculator and said second band-pass filter responsive to an output signal of said second switch determining circuit;
• a 3-line-comb operational circuit coupled to said first inverter, said first switch circuit, and said second switch circuit;
• a subtractor coupled to said first delay circuit and said 3-line-comb operational circuit;
• and
• a filter for filtering an output signal of said 3-line-comb operational circuit.

A 2-line YC separation device for use with a composite input video signal, said device comprising:

• delay means for delaying the composite input video signal and generating a delayed composite video signal;
• filter means for filtering said composite input video signal and said delayed composite video signal;
• correlation means for correlating i) a luminance component and ii) a chrominance component of said composite input video signal and said delayed composite video signal;
• inverter means for inverting an output of said filter means and generating an inverted filtered video signal;
• switching means to selectively couple one of i) the inverted filtered video signal and ii) said filtered video signal to a comb means responsive to an output signal of said correlation means, said comb means producing a combed video signal;
• second filter means for filtering said combed video signal to produce a filtered chrominance signal;
• and
• subtractor means coupled to said first delay means and said comb means for subtracting said combed video signal from said delayed composite video signal to produce a luminance output signal.