Apparatus for generating the magnitude of the vector sum of two orthogonal signals as for use in a digital TV receiver

Apparatus for generating the magnitude values of the vector sums of two component vectors comprising:

• a source of signals corresponding to said two component vectors;
• a source of angle values corresponding to the angle between said vector sum and the axis of one of said two component vectors;
• means responsive to said angle values for generating coefficient values, K, related to said angle values;
• means responsive to said values K for weighting signals applied thereto;
• a summing circuit having a first input port coupled to said weighting means, having a second port and an output port;
• means for coupling one of said two component vector signals from said source to the second input port of said summing circuit and the other of said two component vector signals to said weighting means;
• and
• wherein signal values, C, produced at the output port of said summing circuit represent the magnitude values of the vector sum of said two component vector signals.

Apparatus for generating the magnitude values, C, of the vector sum of two substantially orthogonal vector signals I and Q comprising:

• means for applying said vector signals I and Q;
• means responsive to said I and Q vectors for generating the angle, .theta., between the vector sum of the vectors I and Q and the axis of one of the I and Q vectors;
• means responsive to the angles .theta. for generating signal values, corresponding to coefficients K;
• an adder circuit having first and second input ports and an output port;
• weighting means having a first input port coupled to said means for generating values, K, having a second input port for applying signal values and having an output port;
• means for coupling the output port of said weighting means to the first input port of said adder circuit;
• means for coupling the I vector signals to the second input port of said adder circuit;
• means for coupling the Q vector signals to the second input port of said weighting circuit;
• and
• wherein the values available at the output port are equal to the sums I+KQ at least over a range of values .theta., and the sums I+KQ approximates the magnitude, C, of the vector sum of I and Q.

A TV receiver having a color correction circuitry of the type which performs color correction by effectively rotating the chrominance vector, said circuitry operating on first and second substantially orthogonal color mixture signals and including means for calculating the magnitude and angle of the vector sum of said first and second color mixture signals, said color correction circuitry improved by having simplified magnitude calculating means wherein the improved magnitude calculating means comprises:

• means for producing the absolute values of the first and second color mixture signals;
• means responsive to the calculated angles for generating signals corresponding to values, K;
• means for predetermining the first and second color mixture signal having the lessor magnitude;
• means responsive to the signals corresponding to values, K, for weighting the absolute value of the first and second color mixture signal of lessor magnitude;
• means for summing the weighted color mixture signal with the absolute value of the other non-weighted color mixture signal, the output of the summing means approximating the magnitude of the chrominance signal.