Chapter 7 Sampling 97.3 The Effect of Undersampling: Aliasing 欠采样 混叠 @s <20M x,()≠x() x,()=∑x(m7) Tsina(t-nr) r(t-nr) Let 0= 2 —T x()=∑x(n)Sn( t-nT x,(nr)=x(nr)10 Chapter 7 Sampling §7.3 The Effect of Undersampling: Aliasing 欠采样 混叠 2   s M  ( ) ( ) r x t x t  ( ) ( ) ( ) ( ) sin c r n T t nT x t x nT t nT   + =− − =  − 2 s c T   Let  = = ( ) ( ) ( ) r a n x t x nT S t nT T  + =−   = −      ( ) ( ) r x nT x nT =