AcUs F ture 43 gt BN 2) S(n) frequency spectrum change of ideal sample -29 29 30.Ω Xu C2-C2N≥2N A)=7∑x(a No aliasing C2-2N< aliasing 米1 (3-9x dX(e0)=Xs(1g)l=0/7 aliasing frequency 丌 O=QT XC((O-k2)/7Figure 4.3 s −N  N frequency spectrum change of ideal sample s −N  N aliasing frequency No aliasing aliasing   =−  =  −  k s c s X j k T X j ( ( )) 1 ( )  = T   =− = = − =  k c s T j X j k T T X e X j ( ( 2 )/ ) 1 ( ) ( ) | /     / 2 s  2