Circuit for automatically adjusting signal separation in Y/C seperation comb filter

A signal separation automatic adjusting circuit for a YC separation comb filter, comprising:

• a first signal path for transmitting an image signal;
• a second signal path for transmitting a delayed image signal which is generated by delaying said image signal transmitted through said first signal path for a predetermined time;
• a subtractor for obtaining a chrominance signal by performing a subtraction between said image signal transmitted through said first signal path and the delayed image signal transmitted through said second signal path;
• an adder for obtaining a luminance signal by adding said image signal transmitted through said first signal path and the delayed image signal transmitted through said second signal path;
• reference color burst signal generation means for generating a reference color burst signal having a same phase as a color burst signal included at least in said image signal;
• a residual burst signal level detection circuit for performing a synchronous detection with respect to a color burst signal component in said luminance responsive to said reference color signal, and for generating a level control signal corresponding to a level of said color burst signal component remaining in said luminance signal;
• a first phase detection circuit for receiving said image signal and said reference color burst signal, for performing a phase detection with respect to color burst signal components in said image signal and said reference color burst signal, respectively, and for generating a first phase shift control signal corresponding to a phase difference between said image signal and said reference color burst signal;
• a second phase detection circuit for receiving at least said luminance signal and said reference color burst signal, for performing a phase detection with respect to second color burst signal components in said luminance signal responsive to said reference color burst signal, and for generating a second phase shift control signal corresponding to the phase difference between said reference color burst signal and said luminance signal;
• gain adjusting means for adjusting a gain between said first and second signal paths corresponding to said level control signal generated by said residual burst signal level detection circuit;
• and
• delay adjusting means for adjusting a delay between said first and second signal paths corresponding to said first and second phase shift control signals.