5. Expansion method for 32-points or 64-points FFT

Figure 38:  Block diagram of Radix-2 32-points FFT circuit

By the same expansion token, serial inputs are delayed and inputted into butterfly circuit, and only necessary outputs for FFT are inputted into next butterfly circuit. It is possible for the expansion by the control on Mux. In this way, Radix-2 -points FFT circuit can be designed. Furthermore, also Radix-4 -points FFT circuit can be designed.