A method is disclosed for providing a digital filter system for providing a low pass filter function to a digital input. The method includes the steps of determining a finite impulse response of the input, determining a transfer function of the finite impulse response and providing a polynomial, identifying a plurality of stopband roots of the polymonial that lie in a complex plane, identifying real and complex conjugate pairs for the plurality of stopband roots, and providing coefficients for a complex polynomial that realizes the real and complex conjugate pairs such that a plurality of adjusted stopband roots lie on a unit circle of said complex plane.