40引言 <Example 3. 5> X() 2si2→x=2si2)=2mo ko T ko O=Koo 周期信号 T T-T T, T XK T 2T, o=Koo 2Sin oT, 2丌 discrete signals of a 丌 2丌 TI 0=Ko T ProfJianyu Yang:Understanding of Signals Systems<Example 3.5> 4.0 引言 X j ( )  0 2 0 T T   →  = → 0   = k F s 1 2sinT  1 2T ( ) 0 | X j   =k = of  1 0 1 0 2sin( ) k k T x k T   = 周期信号 0 1 0 2sin( ) k k T Tx k    = 0 1 2sin( ) k T     = =