电子科发女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 3.Impulses and Their Sifting Property A unit impulse of continuous variable 0=gua0i=1 Sifting property f()6()d=f(o) t=( f(t)8(t-1)di=f(o)1=1( ) , 0 , 0, 0 t t t   = =    ◼ Sifting property 3. Impulses and Their Sifting Property f t t dt ( ) ( ) f (0)  − =  f t t t dt ( ) ( 0 ) f t( 0 )  − − =  ◼ A unit impulse of continuous variable s t t dt . . 1  ( )  − =  t = 0 0 t t =