On the evaluation of finite precision coefficients in IIR digital filter design
S.J. Varoufakis, A.N. Venetsanopoulos · International Journal of Electronics · 1988
A simple and effective algorithm is presented for the evaluation of coefficients of reduced word-length in the design of IIR digital filters. The transfer function is expressed as a cascade of second order sections. Each section is considered individually and coefficients of finite precision word-length are derived, using the Pade ' series coefficients in conjunction with a minimum pole displacement approach. The proposed algorithm makes use of two criteria The first criterion preserves a minimum pole displacement, while the second criterion preserves the minimum Pade ' coefficients modification. Once the evaluation of the coefficients has been accomplished the least squares error function is applied in order to check for the total error resulting in the frequency response of the filter. Thus the overall computational effort is reduced substantially. Two examples of one second order section filter and one example of two sections are presented to prove the algorithm' s effectiveness