Stability Condition in Terms of the Pole Locations A causal lti digital filter is BIBO stable if and only if its impulse response h[n] is absolutely summable, i.e

作业： 3.1，3.4，3.5，3.6，3.8，3.10， 3.13，3.15，3.16，3.18，3.20；

Phase and Group Delays The output y[n] of a frequency-selective LTI discrete-time system with a frequency response(@) exhibits some delay relative to the input x[n] caused by the nonzero phase response 0(@) =arg{()} of the system

DTFT Properties Using the differentiation property of the DTFT given in Table 3.2, we observe that the DTFT of nx[n] is given by

Linear-Phase FIR Transfer Functions It is nearly impossible to design linear- phase IIR transfer function It is always possible to design an FIR transfer function with an exact linear-phase response

一、Textbook S.K. Mitra, Digital Signal Processing-A Computer-Based Approach, Third Ed

电子科技大学：《数字信号处理 Digital Signal Processing》课程教学资源（英文讲义）Introduction（彭启琮）

Discrete-Time Systems A discrete-time system processes a given input sequence x[] to generates an output sequencey[n] with more desirable properties In most applications, the discrete-time system is a single-input, single-output system:

3.1 离散傅里叶变换的定义 3.2 离散傅里叶变换的基本性质 3.3 频率域采样 3.4 DFT的应用举例

一、频率响应 二、传输函数 三、简单滤波器 四、一些特殊的传输函数