由x,(n)=Re[w(n)]得 X (k)=DFT[x (n)]=DFT{Re[w(n)]=W(k) =2(》+W(V-,]R( 由x2(n)=Im[w(n)]得 X:(k)-DFTl:()-DFT{Iml(() 子》.-g-.R因 2024/10/211 由 得 x n w n ( ) Re[ ( )] = 1 1 ( ) [ ( )] {Re[ ( )]} ( ) X k DFT x n DFT w n W k = = = ep 1 * [ (( )) (( )) ] ( ) 2 = + − W k W N k R k N N N 2 由 得 x n w n ( ) Im[ ( )] = 2 2 1 ( ) [ ( )] {Im[ ( )]} ( ) X k DFT x n DFT w n W k op j = = = 1 * [ (( )) (( )) ] ( ) 2 W k W N k R k N N N j = − − 2024/10/21 6