16.1 D/A转换器概述 D/A转换器输入的是数字量，经转换后输出的是模拟量。 有关D/A转换器的技术性能指标很多，例如绝对精度、相对精 度、线性度、输出电压范围、温度系数、输入数字代码种类 （二进制或BCD码）等。 1) 分辩率 分辨率是D/A转换器对输入量变化敏感程度的描述，与输 入数字量的位数有关。如果数字量的位数为n，则D/A转换器 的分辨率为2-n。这就意味着数/模转换器能对满刻度的2-n输入 量作出反应

7.12 某一 8086CPU 系统中，采用一片 82C59A 进行中断管理。设定 82C59A 工作在 普通全嵌套方式，发送 EOI 命令结束中断，采用边沿触发方式请求中断，IR0 对应的中断向 量码为 90H。 另外，82C59A 在系统中的 I/O 地址是 300H(A0＝0)和 301H(A0＝1)。请编写 82C59A 的初始化程序段

The idea of Recursive-Descent Parsing Viewing the grammar rule for a non-terminal A as a definition for a procedure to recognize an A The right-hand side of the grammar for A specifies the structure of the code for this procedure The Expression Grammar:

设D是以点A,1),B(-1),C(-1,-1)的三角形,则 √x2+3y2+1)si(xy)+2dy=(A)(中) (A)4.(B)2.(C)1.(D)0 2.设球体x2+y2+z2≤2az(a>0)中每点的质量密度与该点 到坐标原点的距离的平方成反比,则该球体的质量M与质心x坐标X为 (中) (A)M=2ka, X X=-a (C)M=2kma, x=la. (D) M=kma, x=Ia 3.设D={(x,y)∈R2x2+y221>0,f(x,y)在D上连续,在D内可微, f(0,0)=1,D的正向边界为C1。若f(x,y)在D上满足方程 afaf 1 ∫(x,y)

them. A student of music needs as long and as arduous a training to become a performer as a medical student needs to become a doctor. Most training is concerned with technique, for musicians have to have the muscular proficiency of an athlete or a ballet dancer. Singers practice breathing every day, as their vocal chords would be inadequate without controlled muscular support. String players practice moving the fingers of the left hand up and down, while drawing the bow to and fro with the right

目的:对于实对称矩阵A(A=A),求正交矩阵Q(QQ=E), 使得QAQ=A.此时,称A正交相似于对角矩阵A

基变换与坐标变换 设向量空间的基①a1,,a,;基②1,…, 基变换:B,可由a1,…,a,唯一的线性表示,所以有 1=c1a1+c2a2+…+

Cyclic Codes a cyclic code is a linear block code where if c is a codeword, so are all cyclic shifts of c E.g., 1000, 110, 101,011 is a cyclic code Cyclic codes can be dealt with in the very same way as all other lbc s Generator and parity check matrix can be found a cyclic code can be completely described by a generator string G All codewords are multiples of the generator string In practice, cyclic codes are often used for error detection(CRc) Used for packet networks When an error is detected by the received, it requests retransmission

1.复数列的极限设{an}(n=12)为一复数列 ,其中an=an+ibn,又设a=a+ib为一确定的复数 如果任意给定ε0,相应地能找到一个正数 N(a),使|an-aN时成立,则a称为复数 列{an}当n→∞时的极限,记作 此时也称复数列{an}收敛于a

Chapter 3 Pressure-activated membrane processes M. J. LEWIS, Department of Food Science and Technology, The University of Reading, Reading RG6 6AP 3.1 INTRODUCTION Over the last 30 years, a number of membrane processes have evolved, which make use of a pressure driving force and a semi-permeable membrane in order to effect a separa- tion of components in a solution or colloidal dispersion. The separation is based mainly on molecular size, but to a lesser extent on shape and charge. The three main processes