物流的定义 物流:以最小的总费用,按用户要求,将 物质资料从供给地向需要地转移的过程。 主要包括运输、储存、包装、装卸、配送 、流通加工、信息处理等活动 电子商务物流管理:研究最小费用下、配 合电子商务的信息传递、将物质资料从供 给地向需要地转移、满足客户需要的活动

实验5基于 MATLAB的数字滤波器设计 实验目的:加深对数字滤波器的常用指标和设计过程的理解。 实验原理:低通滤波器的常用指标: 1-p≤g(es1+op, for≤p G() 1+0 1-p G(e)o, foros≤o≤n -s -op p @s 通带边缘频率:,阻带边缘频

实验3离散信号的DTFT和DFT 实验目的:加深对离散信号的DTFT和D的及其相互关系的理 解。 实验原理:序列x[n]的DTFT定义:X(e)=x[n]e- n=-∞ N点序列x[n]的DFT定义:

1. Any arbitrary input sequence x[n] can be expressed as a linear combination of delaved and advanced unit sample sequences [n]=x[k][n-k] k=-0 2. .Linear Time-Invariant()System A system satisfying both the linearity and the time-invariance property. .If yiln] is the output due to an input xiln] and y2ln] is the output due to an input x2n] then for an input xn]=axiln]+bx2n] the output is given by ]=]+by2[n]

4.1 LTI Discrete-Time Systems in the Transform Domain · Such transformdomain- representations provide additional insight into the behavior of such systems It is easier to design and implement these systems in the transform-domain for certain applications We consider now the use of the DtFt and the z-transform in developing the transform- domain representations of an LTI system

1.1 Introduction Any problems about signal analyses and processing may be thought of letting signals trough systems. f(t) y(t) h(t) From f(t) and h(t), find y(t), Signal processing From f(t) and y(t), find h(t), System design From(t)andh(t), find(t), Signal reconstruction

Introduction Ideally, the system parameters along with the signal variables have infinite precision taking any value between -oo and · In practice, they can take only discrete values within a specified range since the registers of the digital machine where they are stored are of finite length

6.1 Introduction The convolution sum description of an LTI discrete-time system can, in principle, be used to implement the system For an IR finite-dimensional system this approach is not practical as here the impulse response is of infinite length · However, direct implementation of the IIR finite-dimensional system is practica

3.1 Discrete-Time Fourier Transform Definition- The discrete-time Fourier transform (DTFT) X(eio) of a sequence x[n] is given by jae In general,() is a complex function of the real variable and can be written as X(eio) Xre(eio) +j Xim(eio)

回顾 1、可视化程序设计 2、一字符界面的缺点和图形用户界面的需求 3、可视化程序设计的基本思想 4、使用VB开 Windows发应用程序的优点 5、介绍Visual Basic集成开发环境 6、使用 Visual Basic提供的各种编程控件 7、在 Visual Basic中编译和执行程序