Variable-passband variable-phase digital filter

A digital filter, comprising:

• means for delaying an input signal to produce delayed input signals;
• means for subdividing said input signal and said delayed input signals into subsignals which are weighted by magnitude;
• first storage means, having input address receiving structures coupled to said subsignals, for storing linear combinations of values of said subsignals, weighted by respective weighting factors and producing output signals indicative thereof, output signals indicative of at least a highest weight one of said subsignals having an integral portion and a fractional portion;
• second storage means, having input address receiving structures coupled to said output signals of said first storage means, for storing values indicative of linear combinations of said output signals from said first storage means and for producing output signals indicative of said values, said output signals being indicative of filtered signals.

A method of digital filtering, comprising the steps of:

• delaying an input signal to produce delayed input signals;
• subdividing said input signal and said delayed input signals into subsignals which are weighted by magnitude;
• storing in advance linear combinations of values as weighted by respective weighting factors of each of said subsignals in a first storage means;
• addressing said first storage means using said subsignals, to receive output signals indicative of said values, said output signals of said first storage means from at least a highest weighted subsignal having an integral portion and a fractional portion;
• storing in advance values indicative of linear combinations of output signals from said first storage means;
• using said output signals from said first storage means to address said second storage means;
• and
• using output signals from said second storage means as filterd signals.