Complex filter apparatus for use in an equalizer

Claim 1

A complex filter apparatus for use in an equalizer for correcting an input television signal to produce a filtered output television signal wherein the input television signal includes a complex valued input signal Y having an in-phase and a quadrature input components represented by a real part Y r and an imaginary part Y i and the filtered output television signal includes a complex valued output signal Z having an in-phase and a quadrature output components represented by a real part Z r and an imaginary part Z i , which comprises: an adder for adding the real part Y r and the imaginary part Yi to produce an output of (Y r +Y i ); a first subtractor for subtracting the imaginary part Y i from the real part Y r to produce an output of (Y r -Y i ); a first filter having a filter coefficient (C r +C i ) for multiplying the real part Y r by the filter coefficient (C r +C i ) to generate an output of Y r (C r +C i ); a second filter having a filter coefficient C i for multiplying the output from the first adder by the filter coefficient C i to generate an output of (Y r +Y i )C i ; a third filter having a filter coefficient C r for multiplying the output from the first subtractor by the filter coefficient C r to generate an output of (Y r -Y i )C r ; a second subtractor for subtracting the output of the second filter from the output of the first filter to produce an output Y r (C r +C i )-(Y r +Y i )C i as the real part Z r ; and a third subtractor for subtracting the output of the third filter from the output of the first filter to produce an output Y r (C r +C i )-(Y r -Y i )C r as the imaginary part Z i .