Chap-2_Discrete-time_signals_and_systems.ppt

2010-3-30 Chapter 2 Discrete-time signals and systems 2.1 Discrete-time signals: sequences 2.2 Discrete-time system 2.3 Frequency-domain representation of discrete-time signal and system 2.1 Discrete-time signals: sequences 2.1.1 Definition 2.1.2 Classification of sequence 2.1.3 Basic sequences 2.1.4 Period of sequence 2.1.5 Symmetry of sequence 2.1.6 Energy of sequence 2.1.7 The basic operations of sequences 2.1.1 Definition Discrete-time signals are represented mathematically as sequences (序列) of numbers. A sequence of numbers x, in which the nth number in the sequence is denoted x[n], is formally written as PCM 音频序列（WAV 文件）格式 2.1.2 Classification of sequence Right-side Left-side Two-side Finite-length Noncausal Causal 2.1.3 Basic sequences 2.1.3 Basic sequences 2.1.3 Basic sequences 2.1.3 Basic sequences 2.1.3 Basic sequences 2.1.4 Period (周期) of a sequence 2.1.5 Symmetry (对称) of a sequence 2.1.6 Energy (能量) of a sequence 2.1.7 The basic operations (运算) of sequences Delay (延迟) Time reversal Scalar addition Vector addition Scalar multiplication Vector multiplication 7. Convolution Sum (卷积) 8. Crosscorrelation (相关) 2.1 序列小结 2.1.1 定义 2.1.2 分类 2.1.3 基本序列 2.1.4 周期性 2.1.5 对称性 2.1.6 能量 2.1.7基本运算 2.2 Discrete-time system 2.2.1 Definition：input-output description of systems 2.2.2 Classification of discrete-time system 2.2.3 Linear time-invariant system (LTI) 2.2.4 Linear constant-coefficient difference equation 2.2.5. Direct implementation of discrete-time system 2.2.1 Definition：input-output description of systems 2.2.2 Classification of discrete-time system 2.2.2 Classification of discrete-time system 2.2.3 Linear time-invariant system (LTI, 线性时不变系统) 2.2.4 Linear constant-coefficient difference equation 2.2.5. Direct implementation of LTI system 2.2 离散时间系统小结 2.2.1 定义：系统的输入输出描述 2.2.2 分类（根据输入输出描述） 2.2.3 线性时不变系统的h[n]描述和分类 2.2.4 系统的常系数线性差分方程描述 2.2.5 离散时间系统的直接实现 重点 判断系统类型 (根据输入输出关系判断, LTI根据h[n]判断). LTI的卷积式的物理意义： 输入信号加权组合成输出信号，h[n]就是权重。 常系数线性差分方程与卷积式的异同，递推解法。 IIR与FIR的区别： 2.3