the Transform Domain An LTI discrete-time system is completely characterized in the time-domain by its impulse response {h[n]} We consider now the use of the DTFT and the z-transform in developing the transform￾domain representations of an LTI system

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:

Time-Domain Representation Signals are represented as sequences of numbers, called samples Sample value of a typical signal or sequence denoted as x[n] with n being an integer in the range x[n] defined only for integer values of n and undefined for non-integer values of n

一、预备知识 二、双线性变换 三、低通IIR滤波器设计 四、高通、带通、带阻IIR数字滤波器设计 五、IIR滤波器的谱变换 六、基于加窗傅立叶级数的FIR滤波器设计 七、数字滤波器的计算机辅助设计 八、用Matlab进行数字滤波器设计

一、傅立叶变换－离散时间傅立叶变换（Discrete-Time Fourier Transform，DTFT)（定义、收敛条件、性质）– 离散傅立叶变换（Discrete Fourier Transform，DFT)（定义、性质） 二、Z变换（定义、收敛条件、逆变换、性质）

一､ 数字系统的概念 按一定方式联系起来的一群事物所构成的总 体，称为系统。能够对数字信息进行传递，加工， 处理的电子设备，称为数字系统。 如果把数字系统比喻成一个人,那么数据处 理器就像人的手和脚,能够完成各种操作。但要 想完成一个复杂的工作必须由大脑协调控制；控 制器在数字系统中就起到了大脑的作用

库 库是用来处理重复出现的内容。用户可以将信息收集在库中,使之成为库项目,当需 要这些信息时,直接插入库项目即可。 122.1创建库项目 在 Dreamweaver中,用户可以为网页中的任意元素创建库项目

It is nearly impossible to design a linear￾phase IIR transfer function It is always possible to design an FIR transfer function with an exact linear-phase response Consider a causal FIR transfer function H(z) of length N+1, i.e., of order N:

Later in the course we shall review various methods of designing frequency-selective filters satisfying prescribed specifications We now describe several low-order FIR and IIR digital filters with reasonable selective frequency responses that often are satisfactory in a number of applications

The simple filters discussed so far are characterized either by a single passband and/or a single stopband There are applications where filters with multiple passbands and stopbands are required The comb filter is an example of such filters