Real-factor FFT algorithms
K. Cho, Gábor C. Temes · 2005
The FFT algorithms are described which, like those described by Rader and Brenner, use pure real (or imaginary) constant factors. Since these factors contain\cos(2\pik/N)(or\sin(2\pik/N)), these processes are somewhat better conditioned than those of Rader/Brenner, and are comparably efficient.