Q4、周期卷积和 若Y(k)=X1(k)·2(k) 则(m)=1DFS(k)=∑(Om)(n-m) m=0 ∑x(m)(m-m)4、周期卷积和 1 2 1 0 ( ) ( ) N m x m x n m        1 2 Y (k)  X (k) X (k) 若    1 1 2 0 ( ) [ ( )] ( ) ( ) N m y n IDFS Y k x m x n m   则       