数字信号处理(课件).ppt

1、第一章第一章时域离散信号和时域离散系统时域离散信号和时域离散系统 主要内容主要内容 nnTxtxnTt)(|)(0001)(nnn 0001)(nnnu nNnnRN其它其它0101)(为实数为实数 )()(anuanxn )sin()(nnx T nTtxnxttxnTt)sin(|)()()sin()()(0)(0为为数数字字频频率率 njenx )sin()cos()(000njnenxnj ,.2,1,0 00)2(MeenjnMj )()(nNnxnx)8()8(4sin)4sin()(nxnnnx sin)(sin)(),sin()(0000 NnANnANnxnAnx则有则有设设

2、kNNnxnxnx)2()()()(0 是是周周期期序序列列，则则若若()()()mx nx mnm ()()h nTn )()()()()()()()()(nhnxmnhmxmnTmxmnmxTnymmm 000()()()()()()my nx nn nx mn nmx n n ()()()()()mx nx mnmx nn ()nh n 1001()limlim1nNnnNNnnnah naaa 1()1nh na 01()()()MNiiiiy nb x nia y ni预滤A/DC数字信号处理D/AC平滑滤波ya(t)xa(t)采样量化编码xa(t)x(n)()()()()()()()()()naaananpttnTx tx tptx ttnTx nTtnT ()()()()22()()()aaaasskXjFT x tXjFT x tPjFT ptkTT 1()()()212()()21()aaaskaskXjXjPjXjkTXjjkT 2/)2/sin(/)/sin()(ttTtTttgss dtgxtgtxtyaaa)()()()()()()()()()()()()()sin()/()()/aananananytxnTnTg tdxnTnT g tdxnT g tnTtnTTxnTtnTT 解码零阶保持平滑滤波x(n)xa(t)xa(nT)xa(t)