New low roundoff noise realization of second-order digital filter sections with coefficients which are sum of power-of-two

This paper proposes a modified structure which yields lower output roundoff noise than many well known low-roundoff structures and is free of zero-input limit cycle oscillations. This new low-roundoff structure is based on Bomar´s technique and is obtained by putting the constraints that two of the state-space coefficients be sum-of-two power-of-two terms. Numerical results are included to illustrate the effectiveness of the new technique for narrow-band filters and to compare with other techniques