9.2 decimation-in-time FFT Algorithms flow graph for 8-point decimation in time binary code: x[0] X[O] nnno x[4]o PX[1] WN N=8=23 WR w及 x[2] 3 stages: w时 PX[2] w x[6]o PX[3] N=2m m=log2N x[1叫 X[4] w WN m级：每级乘法 x[5]o →bX[5] 和加法个数为N w x [3]o bX[6] w Computational x[7] X[7] Complexity: WN w WN Nlog2N complex multiplications and additions Nm21 9.2 decimation-in-time FFT Algorithms ◆flow graph for 8-point decimation in time ◆Computational Complexity: ◆Nlog2N complex multiplications and additions N=2m m=log2N N=8=23 binary code: 2 1 0 n n n 3 stages: m级: 每级乘法 和加法个数为N Nm