From: Canonic FFT flow graphs for real-valued even/odd symmetric inputs
P is odd, Q is odd | P is odd, Q is even | P is even, Q is odd | P is even, Q is even | |||||
---|---|---|---|---|---|---|---|---|
P-point | Q-point | P-point | Q-point | P-point | Q-point | P-point | Q-point | |
#REFFT | 1 | 1 | 2 | 1 | 1 | 2 | 1 | 1 |
#RFFT | \(\frac {Q-1}{2}\) | 0 | \(\frac {Q-2}{2}\) | 0 | \(\frac {Q-1}{2}\) | 0 | \(\frac {Q-2}{2}\) | 0 |
#HFFT | 0 | \(\frac {P-1}{2}\) | 0 | \(\frac {P-1}{2}\) | 0 | \(\frac {P-2}{2}\) | 0 | \(\frac {P-2}{2}\) |
\(\#\left (\frac {P}{2}\times 2\right)\) | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
\(\#\left (2\times \frac {Q}{2}\right)\) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |