O* zla0)2 (3)x(n)= (-n-1) 2 x(n)=∑ 2 n=-00 2z 2< m 零点:z=0 极点:z Re[=] 收敛域:解: 1 1 ( ) ( ) 2 n n n n n ZT x n x n z z − − − =− =− = = − 1 ( ) ( 1) 2 n x n u n = − − − (3) 零点: z = 0 极点: 1 2 z = 收敛域: 1 2 z 1 2 n n n z = = − 2 1 2 1 2 z z z z = − = − − 2 1 z Re[ ]z j z Im[ ] 0 1/ 2