Digital video processing system with mixing prefilter

A system for combining digital signals, including:

• an arithmetic logic circuit, including a first input terminal and a second input terminal, and means for combining a signal asserted at the first input terminal with a signal asserted at the second input terminal;
• a first means for supplying a first digital signal representing digitized images to the first input terminal;
• and
• a second means for supplying a second digital signal representing digitized images to the second input terminal, wherein the second means includes:
• means for storing an input digital signal representing digitized images;
• an anti-aliasing filter for receiving the input digital signal and generating a filtered input digital signal therefrom;
• a multiplication circuit having an output terminal connected to the second input terminal of the arithmetic logic circuit, and including means for receiving the filtered input digital signal and generating said second digital signal from the filtered input digital signal, wherein the anti-aliasing filter generates the filtered input digital signal by removing high frequency components thereof that would otherwise result in aliasing error during processing in the multiplication circuit.

A method for combining digital signals representing digitized images, including the steps of:

• (a) filtering a first digital input signal representing digitized images to generate a filtered signal having no significant frequency components with frequency above a first frequency;
• (b) multiplying the filtered signal by a factor signal, with a sampling frequency not less than twice the first frequency, to generate a second digital signal;
• and
• (c) mixing the second digital signal with a third digital signal representing digitized images, wherein the third digital signal is a video field signal, wherein the first digital signal has a magnitude (A-B), where A is the magnitude of a second video field signal and B is the magnitude of the video field signal, and wherein step (c) includes the step of adding the second digital signal to the third digital signal

A method for combining digital signals, including the steps of:

• (a) generating an input digital signal representing a digitized image;
• (b) generating a second digital signal;
• (c) generating a filtered input digital signal from the input digital signal by removing high frequency components of the input digital signal that would otherwise result in aliasing error during the performance of step (d);
• and
• (d) multiplying the filtered input digital signal and the second digital signal to generate a third digital signal, wherein the second digital signal is a selected one of a static multiplicative factor signal and a dynamic multiplicative factor signal, and wherein step (d) includes the step of:
• supplying the selected one of the static multiplicative factor signal and the dynamic multiplicative factor signal to a multiplication circuit for multiplication with the filtered input digital signal.