§7.1基本概念 (4)正弦序列 2丌 x(n =sin na=sinn -(5)复指数序列 x(n)=e mb=x(ne x(n)=1, arg[x(n)I6 §7.1 基本概念 – (4)正弦序列 – (5)复指数序列 ( ) 0 0 2 x n n nT sin sin T  = =  ( ) ( ) ( ) ( ) ( ) 0 j jarg 0 1,arg n x n x n e x n e x n x n n       = = = =    