PROBLEM TO BE SOLVED : To obtain a method for efficiently and quickly changing digital parameters without using a division function singly or in combination with a trigonometric function. SOLUTION : A method 400 for realizing a digital filter quickly generates and re-characterizes the digital filter by utilizing a fast and accurate reciprocal estimate value function. The reciprocal estimate value function quickly and efficiently synthesizes the digital filter without the need for trigonometric and/or division capability and stores an integrated circuit real estate.