清华电工技术2005春补充作业题

2005春季学期补充作业题
1、 电路如1图，求该电路中电源发出的总功率是多少？
2、A bridge circuit is analyzed in the lab .The load is removed and its open circuit voltage is measured to be 10V . The load resistance of 4 k Ω is reattached and the load voltage is measured to be 8V . Find and draw the Thevenin model for this circuit. If a 1k Ω resistor were attached as a load instead of the 4k Ω resistor, what would the load voltage and current be ?
3、已知电路如下图，
若要使输出电压 问：两个电容如何取值
4、阅读下面英文短文
The IEEE and ANSI standard symbol representations of these commons: earth, analog, and chassis return common.
Analog Common Earth Common Chassis Return common In an electronic circuit , it is important to reference a point common to the circuit .
A circuit might have an analog common, a digital common, and an RF (radio frequency) common, which are physically different common point in the circuit.
Metal conducting rods are driven deep into the earth until they reach mineral enriched water The mineral in the water conduct electrically and form a common conducting point we shall refer to it as earth common. Note: it is neither the dirt nor the ground that is conductive; it is the minerals in a water solution in the earth that is common .Thus the terms ground and grounding can be confusing. The term grounding does specifically refer to tying a point to earth common. As the name Chassis return common indicates, the chassis of the equipment is considered a common point, An excellent practical example of this is the automobile chassis, Electrical wire is used to connect to components such as taillights, but the metallic chassis is used as a conductive
rad/s
314
H 12.0V
3sin 2sin 22
1
==+=ωωωL t U t U u i
t
U u o ωsin 21=？
？==21C C u
o
u
return path. This saves wire, weight, and expense, Also , the large, thick conducting frame is a better conductor than wire.
Note the term ground instead of common is in widespread use in the profession. Ground is a confusing term. Also ,be aware that the IEEE standards are not universally followed when using common (or ground) symbols, especially in manufacturer specifications. 5、
设计一个运料小车控制电路，同时满足以下要求： 1. 小车启动后，前进到A 地。

然后做以下往复运动： 到A 地后停2分钟等待装料，然后自动走向B 。

到B 地后停2分钟等待卸料，然后自动走向A 。

2. 有过载和短路保护。

3. 小车可停在任意位置。

6、
设计控制电路，满足对起动后工作台的控制要求：
7. 阅读下面的资料
MAXPLUS-2是美国ALTERA 公司设计的EDA 综合软件，其全称为Mutiple Array Matrix and Programmable Logic User System 。

其9.01以上版本支持VHDL 、AHDL 、V erilogHDL 三种硬件描述语言，同时支持原理图描述。

在原理图输入方式下，为用户提供了prim (Primitive) mf (Macro-founction)、 mega-LMP 三种层次的功能模块。

● prim 是最基本的逻辑单元库，如D 触发器（dff ）JK 触发器（jkff ）与、或、非门；
输入输出端，电源、地等。

● mf 是比prim 复杂的功能块库，例如 记数器74LS90、七段译码器74LS48等，这个库提供了几乎所有74系列数字电路集成芯片的逻辑功能。

● LPM (Library of Parameterized Modules) 是参数化功能模块库。

这些功能模块在使用
上比mf 更为灵活，也更能节省器件资源。

例如实现12bit 宽度的锁存器，如用mf ，则需要使用两片8bit 的74373芯片，将有4个触发器被浪费；如用LMP ,用户可通
ST 3 ST 4 ST 2 ST 1 (1) 运动部件A 从1到2
(2)运动部件B 从3到4
(3)运动部件A 从2回到1
(4)运动部件B 从4回到3
自动循环
过参数设置触发器个数，就避免了这问题。

现代电子技术的飞速发展是集成电路的设计规模日益增大，复杂程度不断提高。

这就使得在设计中电路门级描述变得难以管理，人们不得不采用自顶向下，分层次来设计的方法，并从电路逻辑功能的角度出发，用类似高级软件程序设计语言的硬件描述语言（HDL_ hardware description language ）对电路进行抽象的描述，形成
文本文件；然后通过EDA 软件（比如MAXPLUS_2对此文本文件进行编译、仿真、综合；下载到可编程芯片（PLD 器件）中，完成电路的具体实现。

AHDL 是美国ALTERA 公司的硬件描述语言。

V erilogHDL 是美国Gatway Design Automation 公司开发的硬件描述语言。

VHDL-very high speed integrated hardware description language 是美国国防部委 托德州仪器公司、IBM 和Intermetrics 开发硬件描述语言，VHDL 在1987年被IEEE 接受为硬件描述语言标准，这就是IEEEstd1076-1987{LRM87}，此后该标准又作了若干修改形成新标准IEEEstd1076-1993{LRM93}，这两标准不完全兼容。

8. As you have learned, the two logic symbols shown in Figure 1 represent equivalent operations. The difference between the two is strictly from a functional viewpoint. For the NAND symbol, look for two HIGHs on the inputs to give a low output .For the negative-OR, look for at least one LOW on the inputs to give a HIGH on the output. Using these two functional viewpoints, show that each gate will produce the same output for the given inputs.
8.The NAND and the negative-OR symbols represent equivalent operations, but they are functionally different. For the NOR symbol, look for at least one HIGH on the inputs to give a LOW on the output. For the negative-AND, look for two LOWs on the inputs to give a HIGH output. Using these two functional points of view, show that both gates in Figure 2 will produce the same output for the given inputs.
A B
y
y
A B
y y。