younever_v1.2信号分配表

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梅森公式-信号流图

例4 已知系统信号流图，解：三个回路
求传递函数 X4/X1及 X2/X1。
L
a
d eg bcg
c
有两个互不接触回路
L L
b
deg
f
则 1 d eg bcg deg
1. X 1 X 4 , p1 aef , p2 abcf 1 1 d , 2 1
x2
(g)
x2
x3
x5 L5 a23a35a52
a12 a23 a34 a45 (1 a44 )a12 a23 a35 P 1 (a23 a32 a23 a34 a42 a44 a23 a34 a52 a23 a35 a52 ) a23 a32 a44 a23 a35 a52 a44
2 1 a44
x3
a42 a12
a44 a34 x4 a35 a52 a45 x5
(a)
a23 x2 a32 x3
x1
(d)
x2
x3
互不接触
L1 a23a32
L12 a23a32a44 L2 a23a34a42
(e) (f)
x2
x4 x4 x5 L3 a44 互不接触 L22 a23a35a52a44 L4 a23a34a45a52
E(s)=
R(s)[ (1+G2H2) + (- G3G2H3) ] + (–G2H3) N(s)
1 - G1H1 + G2H2
+ G1G2H3 -G1H1G2 H2
信号流图
R(s) 1
e
g
a
f
b

信号流图梅森公式

回路传输(增益)：回路上各支路传输的乘积称为回路传输或回
路增益。
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信号流图的等效变换
串联支路合并：
ab x1 x2 x3
并联支路的合并：
a
x1 b x2
ab
x1

x3
ab
x1
x2
回路的消除：
ab
x1
x2
x c
3
b
a 1 bc
x1 x2 x3
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信号流图的等效变换
P

1
n k1
Pkk
1 L a L b L c L d L e L f .（.正. 负号间隔）
式中： La 流图中所有不同回路的回路传输之和；
LbLc 所有互不接触回路中，每次取其中两个回
路传输乘积之和；
LdLeLf 所有互不接触回路中，每次取其中三个
18
梅逊公式||例2-15
例2-15：数数有几个回路和前向通道。
G6
R
G5
1
G2
1
G7
G3
G4
1
G1
1
H2
G8
H1
有四个回路，分别是：
1
C
G 2 H 2 , G 1 G 2 G 3 G 4 H 1 , G 1 G 2 G 7 G 4 H 1 , G 1 G 2 G 8 G 4 H 1
ug ue
u1
u2
ua

G f
[解]：前向通道有一条；ug ,P 1G 1G 2G 3G u
有一个回路； L a G 1 G 2 G 3 G u G f

《阿甘正传》任务分配表

电影《阿甘. 正传》任务表I. Drama Films剧情片A drama film is a film genre that depends mostly on in-depth development of realistic characters dealing with emotional themes. Dramatic themes often include current issues, societal ills, and problems, concerns or injustices, such as racial prejudice, religious intolerance, drug addiction, poverty, political unrest, power abuse, alcoholism, class divisions, sexual inequality, mental illness, corrupt societal institutions, violence toward women or other explosive issues of the times.All film genres can include dramatic elements, but typically, films in the genre focus mainly on the drama of the main issue.Drama Films are serious presentations or stories with settings or life situations that portray realistic characters in conflict with either themselves, others, or forces of nature. A dramatic film depicts human beings at their best, their worst, and everything in-between. Dramatic films are probably the largest film genre because they include a broad spectrum of films.Drama films have been particularly appreciated by all kinds of awards. Some well-known drama films include All Quiet on the Western Front (1930), Gone With The Wind (1939), The Graduate (1967), The Godfather (1972), The Longest Yard (1974), Rain Man (1988), Forre st Gump (1994), and Schindler’s List (1993), The English Patient (1996), Titanic (1997) , American Beauty (1999) and Traffic (2000).2. There are many sub-genres of drama films, such as Social Problem Drama, Race Relations and Civil Rights Dramas, Courtroom Dramas, Political Dramas, WWII Homefront Dramas, History-Related Dramas, Sports Dramas, Religious Dramas, Literature-Related Dramas, etc. Which one do you like best, and why?II. Comedy-drama FilmsThe comedy-drama film, also called dramedy or seriocomedy, is a style of television, theatre and film in which there is an equal or nearly equal balance of humor and serious content.Comedy-drama films are a hybrid that merges dramatic films with comic elements or a strong comic lead, in situations that do not necessarily end happily. Instead of presenting the world as neat and clean and full of only laughs and resolution, these films often add dramatic touches like tragedy, melodrama and melancholy while maintaining a light tone. Beginning with the bittersweet social melodrama slapstick of Charlie Chaplin and the modern, lighthearted tragedy of Buster Keaton, the comedy drama originated from the silent era.During the Golden Age, filmmakers Preston Sturges, Howard Hawks, Ernst Lubitsch, and George Cukor mixed drama and comedy in perfect balance, while Billy Wilder perhaps perfected the genre, crafting comedies often addressing dark social and lifestyle issues with Ace in the Hole (2003) and The Apartment (2008). Mike Nichols’s The Graduate (2009), Hal Ashby’s The Last Detail (1973), Shampoo (2004) and Woody Allen’s Hannah and Her Sisters (1986), Crimes and Misdemeanors (2005), carried the tradition into the 1970s and 1980s, often applying an even more cynical edge. Independent cinema, with its focus on daily routines, relationships and angst, used this style with the films of Jim Jarmusch, Richard Linklater, Hal Hartley and Spike Lee. Internationally, filmmakers such as Claude Chabrol, Eric Rohmer, Federico Fellini, Mike Leigh, Takeshi Kitano and Pedro Almodovar have based much of their work in the hybrid between humor and drama.Comedy-dramas have had some strong success in recent years, eg. House M.D. (2004), Desperate Housewives (2004), Psych (2004), Ugly Betty (2006), and Californication (2007). However, some shows, like Studio 60 on the Sunset Strip (2006-2007), have failed to make it past the first season.。

数字信号处理第四版(高西全)第1章

1第1章时域离散信号和时域离散系统第第11章章时域离散信号和时域离散系统时域离散信号和时域离散系统11引言引言12时域离散信号13时域离散系统14时域离散系统的输入输出描述法线性常系数差分方程15模拟信号数字处理方法习题与上机题第1章时域离散信号和时域离散系统11引言引言信号通常是一个自变量或几个自变量的函数
本章作为全书的基础，主要学习时域离散信号的表示方法和典型信号、时域离散线性时不变系统的时域分析方
第1章时域离散信号和时域离散系统
1.2 时域离散信号
实际中遇到的信号一般是模拟信号，对它进行等间
假设模拟信号为xa (t)，以采样间隔T对它进行等间隔采样，得到：
x(n) xa (t) tnT＝xa (nT ) - n （1.2.1）
x(n) x(m) (n m) m
（1.2.12）
这种任意序列的表示方法，在信号分析中是一个很有用的
第1章时域离散信号和时域离散系统
例如， x(n)＝{－0.0000 ，－0.5878 ，－0.9511，
－0.9511，－0.5878，0.0000，0.5878， 0.9511，0.9511，
0.5878，0.0000}，相应的 n=－5, －4, －3,
序列x(n)的MATLAB表示如下:
in (π 8
n)
0
π 8
第1章时域离散信号和时域离散系统
（2） 2π/ω0不是整数，是一个有理数时，设 2π/ω0=P/Q，式中P、Q是互为素数的整数，取k=Q，那么 N=P，则该正弦序列是以P为周期的周期序列。例如, sin(4πn/5), 2π/ω0=5/2, k=2, 该正弦序列是以5为周期的周
axis(［－5, 6, －1.2, 1.2］); xlabel('n'); ylabel('x(n)')

1-2信号描述、运算及分解

哈尔滨工业大学自动化测试与控制系
信号与系统—signals and systems [例]：求下列函数值 ① ③
e

t
t t 1 dt
②

e t t (t )dt
e
1
3
t 2 5t 3
t 2dt
解： t 1 ① (e t ) t 1 dt e 1
0
s(t)
(t )
1
t
求导
ds(t ) 1 dt
0
0 求导 t
③性质
i) ii)
正负两个冲 (t ) 0 激的面积抵消

(t )
2
(t ) f (t )dt f (0)

1
0
t
0 t
0
2
iii) (t t0 ) f (t )dt f (t0 )
信号与系统—signals and systems
1.2 信号描述、运算及分解
• • • • 典型的连续时间信号信号的运算奇异信号信号分解
直流分量与交流分量偶分量与奇分量脉冲分量实部与虚部分量
哈尔滨工业大学自动化测试与控制系
信号与系统—signals and systems

t
0
( 0)
t

哈尔滨工业大学自动化测试与控制系
信号与系统—signals and systems 4．正弦信号
①表达式：
f (t ) K sin(t )
②参数：K 振幅，角频率，初相位
③特性 i)周期信号，T

信号与系统第二章线性时不变系统课件优质课件

y(2) 1 0 2 1 y(3) y(4) y(5) y(6)
y(n) x(n) h(n) { 1, 2, 2,8,3,6,5,1, }
优点：计算非常简单。
缺点：①只适用于两个有限长序列的卷积和；
②一般情况下，无法写出 y(n)的封闭表达式。

x(n) h(n) x(k)h(n k) k

x( ) (t ) x( ) h(t )

x( ) (t )d x( )h(t )d

x(t) y(t)
y(t) x( )h(t )d
表明:连续LTI系统可以完全由它的单位冲激响应
h(t)
x(t)
h1(t)
y(t)
+
h2(t)
y t xth1 t xt h2 t xt h1 t h2 t
yt xtht
ht h1t h2 t
结论：两个LTI系统并联，其总的单位脉冲(冲激)响
一. 用单位冲激信号表示连续时间信号

x( ) (t )d x(t) (t )d

x(t) (t )d
x(t)

x(t) x( ) (t )d
x(t) lim x( ) (t ) 0
为积分变量； 2. 反转：将h()变为h(- )； 3. 平移：将h(- )平移t，变为h[-(-t)]； 4. 相乘：将x()和h(t- )相乘； 5. 积分：求x()h(t- )乘积下的面积。
例: x(t) eatu(t) , a 0
h(t) u(t)

信号与线性系统课件(第5版)管致中期末复习总结课件及应用

1.2 信号的分类及性质
2. 连续信号和离散信号
（1）连续时间信号：
在连续的时间范围内(-∞<t<∞）有定义的信号称为连续时间信号，简称连续信号。
如取值也连续则常称为模拟信号。这里的“连续”指函数的定义域—时间是连续的，但可含间断点，至于值域可连续也可不连续。
（2）离散时间信号：
仅在一些离散的瞬间才有定义的信号称为离散时间信号，简称离散信号。
其中 C0 ,K, Ck−1, Ck+1,K, Cn 也是由系统的初始条件确定的待定系数。
§2.6 阶跃响应和冲激响应
单位冲激响应⎯ 以单位冲激信号作为激励信号时，系统的零状态响应,记为 h(t)。
单位阶跃响应⎯ 以单位阶跃信号作为激励信号时, 系统的零状态响应，记为 rε (t)。
一、冲激响应
§2.2 系统数学模型的建立
1) 构成电路各个元件上的电压和电流的关系。由于所讨论的电路系统最终可以等效为由理想元件电阻、电容、电感所构成，因此应掌握这些元件电压与电流的关系：
R:
uR = R⋅iR
L:
uL
=
L
⋅
diL dt
1t
C:
∫ uC = C −∞ iC (τ )dτ
2) 基尔霍夫电压和电流定律。
连续周期信号f(t)满足
f (t)
f(t) = f(t + mT)，m = 0,±1,±2,…
离散周期信号f(k)满足
t
f(k) = f(k + mN)，m = 0,±1,±2,…
满足上述关系的最小T(或整数N)称为信号的周期。不具有周期性的信号称为非周期信号。
1.2 信号的分类及性质
例1 判断下列信号是否为周期信号，若是，确定其周期。（1）f1(t) = sin2t + cos3t （2）f2(t) = cos2t + sinπt

LTE-上下行参考信号详解

LTE-上下⾏参考信号详解LTE参考信号⽬录LTE参考信号 (1)1.下⾏参考信号 (2)1.1下⾏参考信号的作⽤和分类 (2)1.2Cell-specific参考信号(Cell-specificRS) (3)1.2.1序列产⽣ (3)1.2.2资源映射 (3)1.3MBSFN参考信号(MBSFNRS) (6)1.3.1序列产⽣ (6)1.3.2资源映射 (7)1.4UE-specific参考信号(UE-specificRS) (9)1.4.1序列产⽣ (10)1.4.2资源映射 (10)1.5三种参考信号的⽐较 (12)2.上⾏参考信号 (13)2.1上⾏参考信号的作⽤和分类 (13)2.2上⾏参考序列的产⽣ (15)2.3序列组跳 (17)2.3.1组跳变-u (18)2.3.2序列跳变-v (20)2.4解调参考信号 (22)2.4.1PUSCH 解调参考信号 (22)2.4.2PUSCH 解调参考信号 (23)2.5探测参考信号 (25)2.5.1序列⽣成 (25)2.5.2物理资源映射 (26)2.5.3探测参考信号⼦幀配臵 (27)1.下⾏参考信号1.1下⾏参考信号的作⽤和分类下⾏参考信号有以下⽬的：（1）下⾏信道质量测量。

（2）下⾏信道估计，⽤于UE端的相⼲检测和解调。

Rel10中：Cell-specificRS：⽤于除了不基于码本的波束赋形技术之外的所有下⾏传输技术的信道估计和相关解调，在天线端⼝{0}或{0,1}或{0,1,2,3}上传输。

UE-specificRS：专⽤于数据的解调，只需要对⼀个特定的移动台在它发射的数据块中的资源快中发射，不需要像原来的⼩区特定参考信号那样在整个频带发射。

⽀持PDSCH的单天线端⼝传输，在天线端⼝5或7或8或{7,8,…,v+6}上传输，其中v为层数，最⼤为8。

MBSFN参考信号：⽤于MBSFN的信道估计和相关解调。

在天线端⼝{4}上传输。

P-RS：主要⽤于定位。

清华大学信号与系统§13 信号分解

如在区间 (t1, t2 ) 内满足正交特性，即
t1 t2gi(t)gj(t)d t0 (ij)
t2 t1
gi2(t)dtKi
则此函数集称为正交函数集
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任意函数由n个正交的函数的线性组合所近似
f(t)c1g1(t)c2g2(t)cngn(t)
n
crgr(t) r1
jn1t
n
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第一章练习
• 1-6 （1），（3），（5），（7） • 1-8, • 1-10 （a), (c) • 1-12 • 1-14 • 1-16 • 1-19
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令 d 2 0 则误差能量 2 最小
dc 12
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d 1
d1c2 t2t1
t1 t2[f1(t)c12 f2(t)2 ]d t0
t21 t1 t1 t2d d 1c 2 f1 2(t)d t2tt2f1(t)f2(t)dt
2c12t1 t2 f22(t)dt0
t2 t1
f2
(t)
f
* 2
(t
)dt
两复变函数正交的条件是
t1 t2f1(t)f2 *(t)d tt1 t2f1 *(t)f2(t)d t0
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§1.5 用完备正交集表示信号
2t21 t1 t1 t2
n
f2(t)d t cr2K r
(0t) (t2)
试用sint 在区间（0，2 ）来近似 f (t)
4

信号与系统总复习精品PPT课件

• 要求掌握的内容 1、掌握单位阶跃函数和冲激函数的性质 2、掌握信号脉冲分解的方法 3、掌握阶跃与冲激响应的求解方法； 4. 了解卷积运算的方法 5、熟悉卷积的主要性质 • 典型题目例2.2-1 例2.2-2 例2.2-3 例2.2-4例2.3-1 例2.3-2 例2.4-2 例2.4-4 作业：2.1，2.2，2.4,2.5 2.6 2.7, 2.15 2.16 2.17
4.7-2 例4.7-3，例4.8-1 例4.8-3 例4.8-4
第五章连续系统的S域分析
• 要求掌握的内容 1、掌握拉氏变换定义和收敛域 2、掌握拉普拉斯变换的性质，并能熟练应用 3、熟悉求拉普拉斯逆变换的方法； 4. 掌握系统函数及其求解方法 5、熟悉卷积的主要性质 • 典型题目例5.1-1例5.1-2 例5.1-3，例5.2-1例5.2-2 例5.2-3 例5.2-4 例5.2-5 例5.3-3 例5.3-4 例5.3-6，例5.4-1 例5.4-2
信号与线性系统
总复习
内容回顾
• 1、信号分析
时域：信号分解为冲激信号的线性组合
连续信号频域：信号分解为不同频率正弦信号的线性组合
复频域：信号分解为不同频率复指数的线性组合
信
号
抽
分
样
析
时域：信号分解为脉冲序列的线性组合
离散信号频域：不作要求
z域：信号分解为不同频率复指数的线性组合
• 2、系统分析
7.3-2 例7.3-3 例7.4-1 例7.4-2 例7.4-3
第八章系统的状态变量分析
• 要求掌握的内容 1. 熟悉状态变量、状态方程等状态变量描述法中的基本概念 2. 掌握从一般的输入输出方程以及实际的电路中建立状态方程和输出方

家务劳动分配统计计划表英语作文少点

家务劳动分配统计计划表英语作文少点全文共6篇示例，供读者参考篇1A Plan to Split Up the Chores at HomeMy name is Jamie and I'm 10 years old. I live with my mom, dad, and two younger sisters who are 7 and 5 years old. Our house can get pretty messy sometimes, especially with all the toys and stuff that gets left around. My parents are always telling us kids to clean up after ourselves but it doesn't always happen. I think we need to make a better plan for splitting up the chores so everyone knows what they're supposed to do. Here's my idea:Chore ListFirst, we need to make a list of all the chores that need to be done around the house every week. Here's what I've got so far:• Make beds• Put away clothes and toys• Vacuum floors• Dust furniture• Clean bathrooms• Take out trash/recycling• Load/unload dishwasher• Fold and put away laundry• Help cook meals• Feed pets• Pull weeds in yard• Wash carI'm probably forgetting some things, but that's a good start. The list looks really long when you write it all out! No wonder my mom is always asking us to clean.Deciding Who Does WhatNext, we need to decide who is going to do each chore. We have 5 people in our family, so I think it's fair if each person gets 3 or 4 chores that are their main responsibilities each week. Some chores are too hard for the little kids, and some are too boring or gross for them too. So maybe it would be good if we split it up like this:Mom:• Cook meals• Wash laundry• Clean bathroomsDad:• Take out trash/recycling • Yard work• Wash carMe (Jamie, age 10):• Load/unload dishwasher • Fold and put away laundry • Feed petsSister (Amy, age 7):• Make bed• Put away toys• Dust furnitureSister (Lily, age 5):• Put away clothes• Help clean floorsThat seems like a pretty fair way to split it up based on what we can all reasonably handle. The bigger chores like laundry, bathrooms, and cooking go to the adults. The medium chores like dishes, yard work, and taking out trash go to me and dad. And the little kids just have some light cleaning in their own rooms and common areas.Rewards for Hard WorkersBut how do we make sure everyone actually does their chores without forgetting or trying to get out of them? I think we should have a rewards system to encourage us. Maybe Mom and Dad can buy a bunch of small toys and treats. Then each week, they can give out rewards to whoever did all their chores without being reminded a million times.We could have different levels of rewards too. So if you just did your basic chores for the week, you get a small treat like a candy bar. But if you went above and beyond to help out more, you could get a bigger prize like a new book or small toy. That'll really motivate us!I also think we should have consequences for not doing your chores. Maybe kids who slack off and don't do their jobs for theweek shouldn't get dessert or TV time that week. I know I definitely wouldn't want to miss out on those!Creating a Chore ScheduleThe last part of the Chore Plan is to actually make a schedule for when these chores need to get done. Maybe we could do it like this:Daily Chores:• Make beds• Put away clothes/toys• Feed pets• Load/unload dishwasherWeekly Chores (Saturdays):• Vacuum/sweep floors• Dust furniture• Wash car• Yard work• Take out trash/recyclingMonthly Chores (First Saturday of month):• Change sheets/towels• Clean bathroomsIf we split up the daily chores in the morning before school, it'll be easy to just get them done as part of our regular routine. The weekly chores can be done all together on Saturday as a family. They'll go quicker with all of us helping out. And then maybe Dad can be in charge of doing the bathroom on the first Saturday of each month since that's a bigger nasty job.So that's my plan for setting up an official Chore Distribution system in our house! I think if we follow it, our home will definitely stay a lot cleaner and neater. It'll be a pain at first, but we'll all get used to it. And the rewards will help make it seem more fun. I'm going to go tell Mom and Dad my idea right now! Wish me luck in convincing them...篇2Chore Assignment Statistics PlanHi there! My name is Emma, and I'm a 10-year-old student in 5th grade. Today, I want to talk to you about something that's been on my mind lately – chores! Yup, those pesky little tasks that our parents make us do around the house. But, you knowwhat? I've realized that having a proper plan for assigning chores can actually make things a lot easier and fairer for everyone.You see, in my family, we used to have this thing where my parents would just randomly ask me or my little brother, Jack, to do chores whenever they felt like it. And let me tell you, it was not a fun time. Sometimes, I felt like I was doing way more chores than Jack, and other times, he would complain that he was the one doing everything. It was a mess!But then, one day, my parents had a brilliant idea – they decided to create a "Chore Assignment Statistics Plan." Now, I know what you're thinking, "Emma, that sounds super boring and complicated!" But trust me, it's actually really cool and has made our lives so much easier.Here's how it works:First, my parents made a list of all the chores that need to be done around the house. This includes things like washing dishes, taking out the trash, cleaning our rooms, vacuuming, and so on. Then, they assigned each chore a point value based on how difficult or time-consuming it is. For example, washing dishes might be worth 2 points, while taking out the trash is only 1 point.Next, my parents created a spreadsheet (yes, they're total nerds, but I love them anyway) where they keep track of how many points each of us has earned from doing chores. Whenever Jack or I complete a chore, we get to add the corresponding points to our total.Now, here's the really cool part – my parents set a weekly target for how many points we each need to earn. For me, it's 10 points, and for Jack, it's 8 points (because he's younger and has fewer responsibilities). If we meet our target by the end of the week, we get a reward! It could be something small, like getting to stay up an extra hour on the weekend, or something bigger, like going to the movies or getting a new toy.But wait, there's more! My parents also have a system for tracking who does what chores. They have a chore chart on the fridge, and every week, they switch up the assignments. So, one week, I might be in charge of washing dishes, while Jack takes out the trash. The next week, we swap. This way, no one gets stuck doing the same chores over and over again, and it's really fair.Now, you might be thinking, "Emma, that sounds like a lot of work for your parents!" And you're right, it is. But you know what?It's totally worth it because it has made our home life so much more peaceful and organized.Before the Chore Assignment Statistics Plan, Jack and I would constantly be fighting over who had to do what chores, and my parents would get really frustrated trying to keep track of everything. But now, everything is clear and transparent. We know exactly what's expected of us, and we can see our progress towards our weekly targets right there on the spreadsheet.Plus, it's actually kind of fun to compete with Jack and see who can earn more points each week. We even have a little friendly competition going on to see who can be the "Chore Champion" of the month!But don't worry, it's not all work and no play. My parents make sure to mix things up and keep it interesting. Sometimes, they'll have "Chore Challenges" where we have to complete a certain task in a certain amount of time, and the winner gets a special prize. Or, they'll have "Chore Swap Days" where we get to trade chores with each other for a day.Overall, I'm really glad my parents came up with the Chore Assignment Statistics Plan. It's helped our family become more organized, more fair, and even a little bit more fun! Sure, doing chores will never be my favorite thing in the world, but at leastnow, I know it's all being done in a systematic and transparent way.So, if you're struggling with chore assignments in your own family, maybe you can suggest something similar to your parents. Trust me, it might seem a little complicated at first, but once you get the hang of it, it's a total game-changer!And who knows, maybe you'll even have a little fun with it, like I do. Just remember, the key is to keep things fair, keep things interesting, and most importantly, work together as a team. Because at the end of the day, that's what families are all about – supporting each other and making sure everyone pulls their weight (even if it's just taking out the trash or washing a few dishes).Well, that's all I've got for you today, folks! I hope you found my little chore story interesting and maybe even a little bit inspiring. Now, if you'll excuse me, I've got to go vacuum my room before I lose any more points this week. Wish me luck!篇3My Family's Chore PlanHi! My name is Timmy and I'm 9 years old. In my family, we all have to help out with chores around the house. My parents say it's important for everyone to pitch in and do their part. They made up this really cool "Chore Plan" to keep things fair and organized. Let me tell you all about it!First, my mom and dad wrote down a big list of all the chores that need to get done each week like vacuuming, dusting, taking out the trash, loading the dishwasher, folding laundry, and more. Then they divided up the chores between the four of us - me, my brother Tommy who's 12, my dad, and my mom.We tried to make it equal so nobody had too many hard jobs. My dad has to do things like mowing the lawn, cleaning the gutters, and fixing stuff around the house since he's biggest and strongest. My mom mainly does the cooking, grocery shopping, and laundry. Tommy and I rotate doing simpler jobs like making our beds, feeding the dog, setting the table, and cleaning our rooms.Next, they made this super neat chart to keep track of everything. Across the top it lists all the chores, and down the side it has the days of the week. There are blank squares next to each chore for each day. We use stickers with our initials and putthem in the squares for the chores we're responsible for that day. It makes it really easy to see who needs to do what!On Mondays, I have to make my bed, feed Buster our dog his breakfast and dinner, and set the table for dinner. Tommy has to do the same things plus take out the trash. My dad mows the lawn and does some fix-it jobs if anything is broken. Mom does like 5 or 6 chores - cooking, laundry, cleaning the kitchen and bathrooms. Everybody has a lot that day!Tuesdays are lighter - just my room, the dishes after dinner, and feeding Buster for me. Tommy vacuums downstairs while Mom and Dad clean upstairs and do extra laundry. Wednesdays I'm on trash duty along with making my bed and setting the table. You get the idea!The best part is how we record when chores are complete. We get to put a star sticker or checkmark in each square after finishing that chore! Seeing all those stars and checks build up totally motivates me. Plus, at the end of the week, my parents count up everyone's stars and the person with the most gets a treat like extra dessert or getting to pick the movie we watch. It's awesome!I used to hate doing chores SO much. I would complain and put them off as long as possible until my parents yelled at me.But this new chart system is really cool. It feels like a game trying to get the most stars, and the stickers make it fun. I can clearly see what I need to do and when. And if I ever forget, the chart is right there to remind me.Now I actually get excited to do my chores so I can get my stars! Sometimes Tommy and I even trade chores if ones that day looks too hard for one of us. The chart also shows my parents which of us is struggling with certain chores so they can help or re-assign them.I think every family should have a chore chart like this! It has made getting our household jobs done so much easier and less stressful. My parents don't have to nag us anymore, and Tommy and I fight way less about who has to do which chores. The chart keeps everything fair and organized.Plus, it's teaching me responsibility and showing how we all have to pull our weight as a family. My parents say it's preparing me and Tommy for when we're older and have our own homes to take care of. I'm really building great life habits.So that's our family's awesome Chore Plan! I'm proud of the way we've all bought into it and work together. Doing chores isn't nearly as bad when it's structured and rewarding like this.I'm going to keep rocking my chores so I can earn more stars than Tommy this week!篇4Chore Allocation Chart PlanHey there! My name is Timmy and I'm a 4th grader at Oakwood Elementary School. Today I want to tell you all about my family's new chore allocation chart plan that we started a few weeks ago. It's been super helpful in making sure everyone pitches in around the house and does their fair share of chores and responsibilities.You see, before we had this chart, things were a bit chaotic in my household. My mom was always having to remind me and my sister Jessica to clean our rooms, take out the trash, load the dishwasher and do our other chores. And my dad would sometimes forget to mow the lawn or take the recycling out to the curb. With both my parents working full-time, the housework was really piling up!That's when my mom got this brilliant idea to make a big chore chart for our family. She put it up on the fridge with all our names and pictures at the top. Down the side she listed all the different chores and housework that needs to be done eachweek. Then she made these cute little magnets with our names on them that we can move around the chart.Each Saturday, we have a family meeting to decide who is going to be responsible for which chores that week. We take turns picking chores, so it's fair and nobody gets stuck with the same yucky jobs every week. Say I pick taking out the trash this Saturday, then next week Jessica would have to do it.Some of the chores on our chart are:Loading/unloading the dishwasherFolding and putting away laundryVacuuming the floorsCleaning the bathroomsDustingTaking out the trash/recyclingFeeding the dogMaking bedsCleaning roomsMowing the lawnWashing dad's carI actually don't mind doing chores that much anymore because the chart makes it so clear what I'm responsible for. And if I forget, someone just has to point at my little magnet on the chart and I remember "Oh yeah, that's my job this week!" It's k篇5Chores, Chores, Chores!I don't know about you, but I feel like my parents are always nagging me about doing chores around the house. "Did you clean your room?" "Have you taken out the trash?" "Don't forget to feed the dog!" It's enough to drive a kid crazy!But you know what? I've come to realize that doing chores is actually really important. It helps keep our home clean and organized, and it teaches us responsibility. Plus, when everyone pitches in, it makes the work go a lot faster.That's why my family has created a Household Chores Distribution Schedule. It's this big chart that hangs on the fridge, and it lists out all the different chores that need to be done each week, along with who's responsible for doing them.For example, on Mondays, I'm in charge of vacuuming the living room and my bedroom. My little brother has to dust the furniture and clean the bathroom sink. Mom and Dad tackle the bigger jobs like mopping the floors and doing laundry.The best part is that we rotate the chores every week, so no one gets stuck doing the same boring task over and over again. One week I might be on trash duty, and the next week I'm washing dishes. It keeps things interesting, you know?Of course, there are always those chores that no one really wants to do, like cleaning the litter box or scrubbing the toilets. But we've come up with a genius solution for that – the "Chore Lottery!" Every Sunday, we write down all the really yucky chores on separate pieces of paper, put them in a hat, and take turns drawing one out. Whoever gets picked has to do that chore for the week. It's kind of like a game of chance, but with a lot more scrubbing involved.I have to admit, at first I wasn't too thrilled about the whole chore thing. I mean, who wants to spend their free time doing boring housework? But then my parents explained that by pitching in and helping out around the house, I'm not just making their lives easier – I'm also learning valuable life skillsthat will come in handy when I'm older and have a place of my own.Plus, there's a sense of accomplishment that comes from checking off each completed chore on the schedule. It's like a mini victory every time I vacuum or load the dishwasher. And when the whole family works together, we can often get everything done in just a couple of hours, leaving us with plenty of time to relax and have fun afterwards.Of course, no system is perfect, and there are still times when my siblings and I grumble and complain about having to do our chores. But then my parents remind us of the alternative –living in a pigsty with dirty clothes piled up everywhere and moldy dishes stacked in the sink. Suddenly, spending a few minutes cleaning doesn't seem so bad!So if your parents are always bugging you about pitching in around the house, my advice is to give the Household Chores Distribution Schedule a try. It might just turn those dreaded chores into a fun family activity (well, maybe not "fun" exactly, but at least tolerable). And who knows? You might even discover a hidden talent for making beds or scrubbing toilets!篇6A Chore Routine for My Busy FamilyMy name is Jamie and I'm 10 years old. I live with my mom, dad, older brother Eric (who's 13), and younger sister Lily (she's 7). Our family is always really busy with school, work, activities and just regular life stuff. That's why we decided to make a chore schedule to help keep our house clean and organized!At first, I wasn't too excited about doing chores. Cleaning up just seems like such a drag when you could be playing video games or hanging out with friends instead. But my parents explained that if we all pitch in a little bit, it makes the work go much faster. And I have to admit, it's satisfying when the living room is clean and everything has a place.Here's how our chore schedule works: each week, we rotate who does which chores. That way, no one gets stuck with the same worst jobs over and over again. We made a big list of all the chores that need to be done, like vacuuming, dusting, taking out the trash and recycling, cleaning the bathrooms, loading and unloading the dishwasher, and more. Yuck, I know! But we all have to do our part.My dad used a spreadsheet to make a rotating schedule where each week, we have different tasks assigned to us. Heeven color-coded it for extra fun (not!) - my jobs are green, Eric's are blue, Lily's are pink, mom's are yellow and dad's are orange.We put the schedule up on the fridge so we can easily see what we're responsible for that week. We also have checkboxes to mark off when we've finished each chore. I kind of enjoy getting to check those boxes - it feels like a video game accomplishment in a way! My parents were smart to build in that tiny bit of enjoyment.Okay, so let me walk through what chores I had to do this week, starting from Monday...On Monday, I had to collect all the dirty clothes from around the house and bring them to the laundry room. I don't mind this job too much because I get to hunt around for smelly socks under beds - it's kind of a fun scavenger hunt! Eric had to actually run the washing machine for the clothes I collected.Tuesday was dusting day for me. I had to go around with a rag and dust all the surfaces in the living room, like the TV stand, side tables, and shelves. This is one of the more tedious chores for sure. For some reason, I find dusting the worst! Eric's job was vacuuming the living room and hallways.Wednesday, I got a bit of a break while Eric had to clean the upstairs bathroom - sink, toilet, tub, the whole deal. I just had a light chore of loading up the dishwasher with all the dirty cups, plates and utensils around the kitchen. Easy peasy!Things picked up again on Thursday when it was my turn to vacuum the stairs, hallways and my bedroom. I don't mind vacuuming too much, though getting under beds is kind of a struggle. While I was doing that, Lily had to go around the house collecting any garbage and taking the trash bin out to the curb.Finally, on Friday I was on dish duty again - unloading the clean dishes from the dishwasher and putting them away in the cupboards. Lily helps me with this one, so we can knock it out pretty quickly together when she's not horsing around too much!Saturdays and Sundays are our days off from weekly chores, though we still have to tidy up after ourselves with bed-making, putting away toys and games, and not leaving messes around. But no officially scheduled chores, which is awesome!Other than the weekly rotating jobs, there are also some monthly chores we share. Like cleaning the oven (not my favorite), sanitizing the trash cans, and washing pillows and blankets. We take turns doing these bigger chores too.My dad gets on us to stay on schedule and not fall behind, but he also gives us rewards when we've pulled our weight for a few weeks straight. Generally, he'll let us pick a special snack or rent a movie we want on those weekends. A little incentive goes a long way with kids!Overall, I don't love doing chores of course. What kid does? But I've gotten used to our routine and it does make me feel more responsible and grown-up. It's kinda cool to look around and see everything clean and in order, and know that I did my part to help out.I think having a chore chart is important, especially for bigger families like mine where there's always a mess to clean up somewhere. If we just left it all to my poor mom, she'd go crazy! This way, the work is spread out and it's clear who is supposed to do what. No more kids saying "I didn't know I had to..." - we know exactly what our jobs are.It's teaching me and my siblings about hard work, pitching in, and not taking things for granted. Yeah, chores are a drag, but I'm learning that keeping a household going is hard work! This rotation also shows us that everyone has to do their part, and that all the jobs are important - not just the "cool" ones.Even little kids like Lily have responsibilities now. In a few years, I'm sure she'll be just as annoyed as me about having to dust and vacuum. But we're building good habits that will last forever.Chores definitely aren't my favorite part of the week, but our schedule does make it a lot more manageable and fair. I'll take dusting and vacuuming over a total pigsty of a house any day!。

信号与系统课件第5章cy

26
（对L 展开）
27
注意到也以为周期，于是有：
比较: 可以看出与连续时间傅立叶变换中相应的形式是完全一致的。
28
例1. 周期的。当
它不一定是时才具有周期性。
如图所示:
29
例2.
均匀脉冲串
比较:与连续时间情况下对应的相一致。
30
5.3 离散时间傅立叶变换的性质
Properties of the Discrete-Time Fourier Transform
称为周期信号的功率谱。
38
5.4 卷积特性( The Convolution Property )
若则
即是系统的频率特性。说明：该特性提供了对LTI系统进行频域分析的理论基础。
39
例:求和特性的证明
40
5.5 相乘性质（The Multiplication Property)
如果则
由于
1
3. 对LTI系统建立了频域分析的方法。 4. 对由LCCDE描述的LTI系统，可以很方便地由LCCDE或系统框图得到其。 5. 稳定的LTI系统可以通过其频率响应来描述。 6. 建立了系统互联时，系统频率响应与各子系统频率响应的关系。
2
第5章离散时间傅立叶变换
（The Discrete-Time Fourier Transform）主要内容
61
• 与连续时间LTI系统一样，对由LCCDE或由方框图描述的LTI系统，可以很方便的由方程或方框图得到系统的频率响应函数H(ejω)，进而实现系统的频域分析。其基本过程和涉及到的问题与连续时间LTI系统的情况也完全类似。
随着今后进一步的讨论，我们可以看到CFS、 DFS、CTFT、DTFT之间是完全相通的。

语法填空

• 2.Though she is a girl , she is interested___in____ football.
• 3.My sister was against my suggestion while my brother was _i_n__ favour of it.
. 4.The new boy looked at the teacher __fo_r_ a few
连接性副词连词
however, therefore…… 从句引导词（定语从句，名词性从句，状语从句）并列连词（and, but, or, so 逻辑关系）情态动词，强调动词（do）等
考点1：介词 (1)介词+宾语（名词） (2)不及物动词+介词+宾语
• 1.I think it’s a good idea___f_o_r__you to come back to China.
考点4：②并列连词或从句引导词
两个句子（即两个主谓结构）之间，如果没有分号或句号，也没有关联词连接或引导，则填并列连词或从句引导词
1. He was very tired after doing this for a whole day, _b_u_t__ he felt very happy.
seconds.
解题技巧：句子不缺主语、表语、动词后不缺
宾语的情况下，名词或代词前面，一定是填介词。
介词的考查：多数情况下出现在__固_定__搭__配______ 中
备考建议：积累常用介词，牢记固定搭配
考点2：代词(pronoun)
人称代词，物主代词，不定代词，指示代词，反身代词代词作主语和宾语的正确形式 It 做形式主语和形式宾语的固定句式

信息论与编码习题解答

信息论与编码习题解答第一章1.一位朋友很不赞成“通信的目的是传送信息”及“消息中未知的成分才算是信息”这些说法。

他举例说：我多遍地欣赏梅兰芳大师的同一段表演，百看不厌，大师正在唱的正在表演的使我愉快，将要唱的和表演的我都知道，照你们的说法电视里没给我任何信息，怎么能让我接受呢？请从信息论的角度对此做出解释。

（主要从狭义信息论与广义信息论研究的内容去理解和解释）答：从狭义信息论角度，虽然将要表演的内容观众已知，但是每一次演出不可能完全相同。

而观众在欣赏的同时也在接受着新的感官和视听享受。

从这一角度来说，观众还是可以得到新的信息的。

另一种解释可以从广义信息论的角度来分析，它涉及了信息的社会性、实用性等主观因素，同时受知识水平、文化素质的影响。

京剧朋友们在欣赏京剧时也因为主观因素而获得了享受，因此属于广义信息论的范畴。

2．利用下图（图1.2）所示的通信系统分别传送同样时间（例如十分钟）的重大新闻公告和轻音乐，它们在接收端各方框的输入中所含的信息是否相同，为什么？图1.2 通信系统的一般框图答：重大新闻是语言，频率为300~3400Hz，而轻音乐的频率为20~20000Hz。

同样的时间内轻音乐的采样编码的数据要比语音的数据量大，按码元熵值，音乐的信息量要比新闻大。

但是在信宿端，按信息的不确定度，信息量就应分别对待，对于新闻与音乐的信息量大小在广义上说，因人而异。

第二章1．一珍珠养殖场收获240颗外观及重量完全相同的特大珍珠，但不幸被人用外观相同但重量仅有微小差异的假珠换掉1颗。

（1）一人随手取出3颗，经测量恰好找出了假珠，问这一事件大约给出了多少比特的信息量；（2）不巧假珠又滑落进去，那人找了许久却未找到，但另一人说他用天平最多6次能找出，结果确是如此，问后一事件给出多少信息量；（3）对上述结果作出解释。

解：（1）从240颗珍珠中取3颗，其中恰好有1颗假珠的概率为：22393240239!2!237!240!3!237!11/80240/3C P C⨯⨯====所以，此事件给出的信息量为：I = – log 2P = log 280=6.32 (bit)（2）240颗中含1颗假珠，用天平等分法最多6次即可找到假珠，这是一个必然事件，因此信息量为0。

多维数字信号处理

• 已知 xn un un 10 ，要求将他们进行奇偶分解，分解为奇偶两个序列。根据一维实验结果，设计产生二维离散信号。
n=[0:13]; n1=14; x=[(n-0)>=0]-[(n-10)>=0]; figure(1); subplot(3,1,1); stem(1:n1,x); title('矩形脉冲 u[n]-u[n-10]') xlabel('n');ylabel('x(n)'); axis([-5,15,0,2]) k=1;l=1;
• 已知x[n]=u[n]-u[n-10]，要求将他们进行奇偶分解，分解为奇偶两个序列。根据一维实验结果，设计产生二维离散信号
• 已知序列
• • • •
a. b. c. d.
画出 x[n]; 画出 y1 [n] x[n 2] 画出 y 2 [n] x[n 1] 画出 y 3 [n] x n]
f (t ) a0 a1 cos(1t ) b1 sin1t

a2 cos21t b2 sin21t an cosn1t bn sinn1t
n 1
a0 an cosn1t bn sinn1t
按照时间函数取值的连续性与离散性可将信号划分为连续时间信号与离散时间信号 • 数字信号处理连续与离散时间信号特征
时间轴(横坐标) 幅度轴(纵坐标) 连续离散统称连续模拟量化连续时间离散抽样数字离散时间
多维数字信号
• 作为一维信号一个自变量 t;
U（t）
t
• 二维信号两个自变量 t1 和 t2 ;
2 1 x[n] 1 3 0

2-5_信号流图与梅森公式

G (s) C ( s ) 2
H(s)
H (s)
N(s)
R(s) +
4
E(s)
_
G(s)
+
+
N(s)
R( s)
C(s)
1 E (s)
G (s)
1
1 C (s)
C ( s)
H (s)
H ( s)
+ +
R1 ( s )
G11 ( s )
C1 ( s)
R1 ( s )
G11 ( s )
C1 ( s )
2. 求 Pk , k
P1 G1G2G3G4G5G6
1 ?
23
求余子式1
H4 R(s)
-
G1
-
4
-
G2 H2
G3
2
G4 H3
G5
3
G6
C(s)
1
H1
将第一条前向通道从图上除掉后的图，再用特征式的求法，计算 1
24
求余式1
H4 R(s)
-
G1
-
4 G4
-
G2 H2
G3
2
G5 H3
-
G1
-
G2 H2
G3
-
G4 H3
G5
G6
C(s)
H1

前向通路数：n＝1
15
P1 G1G2G3G4G5G6
求解步骤之二（例1）

确定系统中的反馈回路数
H4
-
R(s) G1
-
G2 H2
G3
-
G4 H3
G5
G6
C(s)

信号与系统基础知识

第1章信号与系统的基本概念1.1引言系统是一个广泛使用的概念，指由多个元件组成的相互作用、相互依存的整体。

我们学习过“电路分析原理”的课程，电路是典型的系统，由电阻、电容、电感和电源等元件组成。

我们还熟悉汽车在路面运动的过程，汽车、路面、空气组成一个力学系统。

更为复杂一些的系统如电力系统，它包括若干发电厂、变电站、输电网和电力用户等，大的电网可以跨越数千公里。

我们在观察、分析和描述一个系统时，总要借助于对系统中一些元件状态的观测和分析。

例如，在分析一个电路时，会计算或测量电路中一些位置的电压和电流随时间的变化；在分析一个汽车的运动时，会计算或观测驱动力、阻力、位置、速度和加速度等状态变量随时间的变化。

系统状态变量随时间变化的关系称为信号，包含了系统变化的信息。

很多实际系统的状态变量是非电的，我们经常使用各种各样的传感器，把非电的状态变量转换为电的变量，得到便于测量的电信号。

隐去不同信号所代表的具体物理意义，信号就可以抽象为函数，即变量随时间变化的关系。

信号用函数表示，可以是数学表达式，或是波形，或是数据列表。

在本课程中，信号和函数的表述经常不加区分。

信号和系统分析的最基本的任务是获得信号的特点和系统的特性。

系统的分析和描述借助于建立系统输入信号和输出信号之间关系，因此信号分析和系统分析是密切相关的。

系统的特性千变万化，其中最重要的区别是线性和非线性、时不变和时变。

这些区别导致分析方法的重要差别。

本课程的容限于线性时不变系统。

我们最熟悉的信号和系统分析方法是时域分析，即分析信号随时间变化的波形。

例如，对于一个电压测量系统，要判断测量的准确度，可以直接分析比较被测的电压波形)(in t v （测量系统输入信号）和测量得到的波形)(out t v （测量系统输出信号），观察它们之间的相似程度。

为了充分地和规地描述测量系统的特性，经常给系统输入一个阶跃电压信号，得到系统的阶跃响应，图1-1是典型的波形，通过阶跃响应的电压上升时间（电压从10％上升至90％的时间）和过冲（百分比）等特征量，表述测量系统的特性，上升时间和过冲越小，系统特性越好。

信号与系统知识点图谱

6-6-1 稳定系统的定义 6-6-2 系统稳定的充分必要条件 6-6-3 极点与系统稳定性的关系
6-6-4-1 罗斯-霍维茨判据
6-6-4-2 罗斯-霍维茨判据应用—— 确定使得系统稳定的参数取值范围
6-7-1 反馈系统及其稳定性
6-7-2 反馈系统与控制论简介
6-6-4-3罗斯-霍维茨判据— —出现首例为0情况的处理
7-2-2 抽样定理
7-2-3 实际应用中的抽样与恢复
7-3-1 离散时间系统的数学模型 7-3-2 离散时间系统的框图
7-4-1 差分算子描述 7-4-2 差分方程零输入响应的求解 7-4-3 离散时间系统的特征根与稳定性
7-5-1 差分方程零状态响应的卷积和求解法 7-5-2 卷积和的计算 7-5-3 卷积和的性质
2-8-3 二阶系统的冲激响应的求解
2-7-2 卷积的性质
2-7-3 几个特殊卷积计算结果
2-8-4 任意阶系统的冲激响应的求解
2-9-1 零状态响应以及全响应时域法求解过程与例题
2-9-2 自然、受迫响应与零输入零状态响应之间的关系等
2-9-3 系统在几个特定激励信号下的响应
3-1 引言 3-2-1 矢量的正交分解 3-2-2 信号的正交分解
注：标注为
1-4-1 系统的
概念
1-4-2Байду номын сангаас统的描述 1-4-3(1)系统的分类(1)
1-4-3(2)系统的分类(2) 1-4-4 增量线性系统与零状态-零输入响应
1-5-1 线性非时变系统分析
1-5-2线性非时变系统的分析方法
的部分为可选部分。
2-1-1 连续时间系统数学模型 2-1-2 微分方程的经典解法 2-1-3 微分方程的近代解法简介 2-7-1 卷积定义及计算