同济大学：《数字信号处理（DSP）》课程教学资源（PPT课件讲稿）第三章 离散傅里叶变换（习题讲解）

一、DFS 二、DFS的性质 三、DFT 四、DFT的性质 五、圆周卷积 六、利用DFT计算线性卷积 七、频率域抽样

一、Z变换的定义与收敛域 二、Z反变换 三、系统的稳定性和H(z) 四、系统函数

Transform-Domain Representation of Discrete-Time Signals Three useful representations of discrete-time sequences in the transform domain: Discrete-time- Fourier Transform(DTFT) YDiscrete Fourier Transform(DFT) z- -Transform

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

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

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

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:

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、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