[工学]BMIE_DSP_Chap2New.pdf

Chapter 2 Discrete-time systems Lisheng XU Yin DAI 2010-09-15 1 Chapter 2 Discrete-time systems 2.1 Discrete-time system 2. 2 Input and output of LSI system 2.3 Frequency response of LSI system 2.4 Definition of Z-transform 2.5 Convergence region of Z-transform 2.6 Z-transform properties 2.7 Inverse Z-transform 2.8 Transfer function of discrete system 2.9 Structure of discrete system 2010-09-15 2 Chapter 2.1 Discrete-time systems 2010-09-15 3 2.1 Discrete-time systems x (n) fi h(n) fi y (n) y (n) = T [x (n)] Description on continuous system Differential equation , convolution, transfer function (Laplace transform), frequency response (Fourier Transform) Description on discrete system Difference equation , convolution , transfer function (Z Transform), frequency response (DTFT, DFT) 2010-09-15 4 For examp le : y (n) = ay (n - 1) + x (n ) fl fl Current time Last time Differential equation 2010-09-15 5 1 M -1 For examp le : ( ) = ( - ) y n Âb x n k k M k =0 if M = 3: 1 y (n) = [b x (n) + b x (n - 1) + b x (n - 2)] 0