A simple FFT butterfly arithmetic unit

A very simple computational requirement is developed for the FFT butterfly. Based upon the distributed arithmetic of Peled and Liu, and upon an algebraic substitution of Bfittner and Schiissler, an architecture develops which uses as weighting coefficients not
\sin (n\theta)
and
\cos(n\theta)
but
\cos(n\theta)\pm \sin(n\theta)
. The resulting serial arithmetic structure is very simple to implement.