Method for reducing digital filter coefficient word size and apparatus therefor

A method for determining sets of coefficient words for a digital filter, comprising:

• a. determining a set of coefficient words for said digital filter for a predetermined frequency value, a predetermined quality factor, and a predetermined sampling frequency;
• b. determining a gain error value for said digital filter for said set of coefficient words;
• c. if said predetermined frequency value is less than a predetermined frequency threshold and said determined gain error value is greater than a predetermined gain error threshold, modifying said quality factor by a first predetermined amount and repeating (a) through (c) using said modified quality factor;
• and
• d. changing said predetermined frequency value by a second predetermined amount to thereby form a new frequency value and repeating (a) through (d) using said new frequency value if said new frequency value is within a predetermined frequency band so as to determine a set of coefficient words for said digital filter:
• wherein the steps of determining the set of coefficient words, determining the gain error value and determining said set of coefficient words are performed by a processor.

An apparatus for determining a set of coefficient words for a digital filter, comprising:

• said digital filter;
• circuitry for determining a set of coefficient words for said digital filter for a predetermined frequency, a predetermined quality factor, and a predetermined sampling frequency;
• circuitry for determining a gain error value for said digital filter for said set of coefficient words;
• and
• circuitry for modifying said quality factor by a predetermined amount and redetermining said set of coefficient words using said modified quality factor if said determined gain error value is greater than a predetermined threshold.

A non-transitory computer readable medium having machine executable instructions for performing a method for determining a set of coefficient words for a digital filter, the method comprising:

• a. determining a set of coefficient words for said digital filter for a predetermined frequency, a predetermined quality factor, and a predetermined sampling frequency;
• b. determining a gain error value for said digital filter for said set of coefficient words;
• and
• c. if said determined gain error value is greater than a predetermined threshold, modifying said quality factor by a predetermined amount and redetermining said set of coefficient words using said modified quality factor so as to determine a set of coefficient words for said digital filter.