I want to implement a radix-8 FFT for a 512-point. I would be happy if any of u could help me out regarding this. Please send any material or papers you have related to radix-8 fft. thanks in advance.
Steven G. Johnson and Matteo Frigo, "A modified split-radix FFT with fewer arithmetic operations", IEEE Trans. Signal Processing 55 (1), 111–119 (2007).