出②式有F0)-m7.fOk-moah T o q 由①式有 fOt\ lim 2 F() mon T->∞2 T lim F(in。),o△ 2 f(2)1 F(oedo ●@0 (4 2兀由②式有 dt jnωt f (t)e T T T F(j T T T 0 2 2 lim 1 ) −   → =  − 0 0 0 0 0 2 lim ( ) lim ( ) ( )       =   =   −  − → → j n t j n t e F jn e T F jn f t T T 由①式有 0  dt③ j t F(j ) f(t)e T nω ω -   −  =     → →  ④   f t F j e d j t  =   − ( ) 2 1 ( )