由傳立叶变换对可知 F(0)=f()dt 当imf(t)=0 t→> f(0)1r 2 F()d当limF()=0 →>+o∞由傅立叶变换对可知:    −  − = =    f F d F f t dt ( ) 2 1 (0) (0) ( ) 当 当 lim ( ) 0 lim ( ) 0 = = → →   F f t t