Improve of DFT Digital Signal Processing--DFT/FFT Algorithms Symmetry (Wt)=W Periodicity Wik-WNim)k -WaNk) WWINW W W=1 W2=-1 WW+N/2）=-W DIT:Decimation-In-Time DIF:Decimation-In-Frequency 上游充通大￥Digital Signal Processing—— DFT/FFT Algorithms Improve of DFT   * nk nk W W N N   nk N n k n N k ( ) ( ) W W W N N N     nk mnk W W N mN  / / nk nk m W W N N m  0 1 WN  / 2 1 N WN   ( /2) k N k W W N N    Periodicity Symmetry DIT: Decimation-In-Time DIF: Decimation-In-Frequency