11.39 Consider the computation of a 12-point DFT X[k] of a length-N sequence x[n]. The index mapping to be used can be either n = (An1 + Bn2)12, k = (Ck + Dk2)12, or n = (Cni + Dn2)12, k = (Aki + Bk2) 12, = where A, B, C, and D are appropriately chosen constants. Use of the mapping g[N1, n2] results in x[(Ani + Bn2)12] 2 3 (11.118) G[k, k2] = 8[11,12]W"2k2 Wk, ni=0n2=0 X[(Cki + Dk2)12] = G[ki, k2]. (11.119) If, on the other hand, the index mapping used is h[n1, n2] = x[(Cn1 + Dn2)12], we obtain 2 3 (11.120) H[k1, k2] = h[11, n2]W"2k2 w.k, ni=0 n2=0 Y [(Aki + Bk2)12] = Hk1, k2]. (11.121) What is the relation between X [k] and Y [k]? 11.39 Consider the computation of a 12-point DFT X[k] of a length-N sequence x[n]. The index mapping to be used can be either n = (An1 + Bn2)12, k = (Ck + Dk2)12, or n = (Cni + Dn2)12, k = (Aki + Bk2) 12, = where A, B, C, and D are appropriately chosen constants. Use of the mapping g[N1, n2] results in x[(Ani + Bn2)12] 2 3 (11.118) G[k, k2] = 8[11,12]W"2k2 Wk, ni=0n2=0 X[(Cki + Dk2)12] = G[ki, k2]. (11.119) If, on the other hand, the index mapping used is h[n1, n2] = x[(Cn1 + Dn2)12], we obtain 2 3 (11.120) H[k1, k2] = h[11, n2]W"2k2 w.k, ni=0 n2=0 Y [(Aki + Bk2)12] = Hk1, k2]. (11.121) What is the relation between X [k] and Y [k]