pfizer电子信息与通信工程专业英语期末必考翻译

2021年1月24日发(作者：joan什么意思)
机电控制工程基础















































communication signals
函数的傅里叶表
implemented
in
hardware,
firmware,
and
zero at the endpoints
如果信号有急剧


















1.
most
cases,
these
signals
originate
as
sensory
data
from
the
real
world:
seismic
vibrations visual images, sound waves, etc.
DSP isthe mathematics, the algorithms, and
the
techniques
used
to
manipulate
these
signals after they have been converted into a
digital form.< br>在大多数情况下，这些信
号来源于人对真实世界的感觉，比如地
震的震动，视觉图像，声 音波形等。数
字信号处理是一种数学工具，是一种用
来处理那些将上述信号转换成数字形式后的信号的算法和技术。

r
’
s representation of functionsas a
superposition
of

sines
and
cosines
has
become Ubiquitous for both the analytic and
numerical solution of
differential equations
and
for
the
analysis
and
treatment
of
示，即将函数表示成正弦和余弦信号的
software
that
operates
on
a
digital
input
叠加，这种方法已经广泛用于微分方程
signal to produce a digital output signal for
的解析法和数值法求解过程以及通信信
achieving filtering objectives.
数字滤波器
号的分析和处理。

是一种数学算法，它可以用硬件，固件

f
(t
)
is
a
nonperiodic
signal,
the
和软件来实现。它作用于数字输入信号
summation
of

the
periodic
functions
,such
产生数字输出信号从而达到滤波目标。

as
sine
and
cosine,
does
not
accurately
basic idea of
Fourier series method is
represent the signal. You

could

artificially

to

design
an
FIR
filter
that
approximates
extend
the

signal

to

make

it

periodic

the
desired
frequency
response
of

filter
by
but

it

would

require
additional
calculating its impulse response.

用
傅
continuity at the end points .
如
果
f(t)
是
里叶级数设计
FIR
滤波器的基本的理念
非周期信号，那么用周期函数例如正弦
是计算出此 滤波器的单位冲激响应来逼
和余弦的和，并不能精确的表示该信号
近所期望的滤波器的频率响应 。

f(t)
。你可以人为的拓展这个信号使其具


有周期性，但是这要求在端点处附加连
6.
the
signal
has
sharp
transitions,
it
is
续性

necessary to window the

4.A digital filter is a mathematical algorithm
input data, so that the sections converge to
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的过渡，就有必有对输入信号加窗，这
样信号在端点处就会收敛于零。

7.
signals and systems aris
e in a wide

variety of
fields, and the ideas and techniqu
es associated

with these concepts play an important role i
n such diverse

areas of
science and technology as commun
ication,

aeronautics and astronautics, circuit design,
acoustics,

seismology, biomedical engineering, energy
generation

distribution systems, chemical process contr
ol, and speech

processing.
信号与系统的概念出现在
机电控制工程基础

广阔的范围内，
在科学 技术的不同领域，
如通信、航空航天、电路设计、声学、
地震学、生物学、生物医学工程、发电
和输电系统、化学过程控制和语音处理
中都离不开这个概念的思想与技术。它
在科学技 术中发挥了重要作用。

8.

characterization of a system requires a com
plete input-out-put relationship, knowing th
e output of
a system to a certain set of
inpu
t doe not allow us to determine the output o
f
the system to other sets of
inputs.
当
系统的特性描 述要求完整的输入输出关
系时，如果没有约束条件，即使知道了
系统对某

些 特定输入产生的输出时，
我
们也并不知道系统对其他输入产生的输
出。

example of
a finite-energy signal is a si
gnal that takes on the value 1 for 0
≤
t
≤
been sampled.
我们可以在抽样的概念下
1 and 0 otherwise.
举一个有限能量信 号
将连续时间和离散时间系统放在一起考
的例子：
信号在
0
≤
t
≤
1
，
而在其他时间
虑。我们可以将一些离散时间系统的概范围取值为
0
。

念推广，用以处理抽样后的连续时间系
, of
course, makes sense, since if
the
统。

re is a nonzero average energy per unit time,
of
the most important motivations
then integrating or summing this over an in
for the development of
general tools for an
finite time interval yields an infinite amount
alyzing and designing systems is that
of
energy.
当
然这是有意义的，因为如果
systems from many different applications ha
单位时间内存在一个非零的平均能量，
ve very similar
mathematical descriptions.
那么在一个无限的时间间隔范围内，对

许多具有不同应 用的系统都有相类
其积分或者求和就会产生一个无限的能
似的数学描述，这是开发系统分析和设
量总和。

计通用工具软件的最重要的动机之一。

can bring continuous-time and discre
onic
amplifiers
are
often
te-time systems together through the conce
symbolized by a simple triangle shape ,where
pt of
sampling, and we can develop some in
the internal components are not individually
sights into the use of
discrete-time systems
represented.
电子放大器一般都表示成
to process continuous-time signals that have
三角形形状，内部器件并不分别表示出
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来。

14..An
increasingly
positive
voltage
on
the(+)input tends to drive the output voltage
more
positive,and
an
increasingly
positive
voltage
on
the(-)input
tends
to
drive
the
output voltage more negative.
增大同向 输
入端的电压，会使输出电压增大；增大
反向输入端的电压，
会使输出电压减小。
e we know that both inputs of the
op- amp
have
extremely
high
impedance,we
can safely assume they won't add or subtract
any current through the divider.
因为我
们知道，运算放大器的两个输入端之间
有无穷大的电阻，所 以我们完全可以假
设他们没有增加或分担任何电流。

other words,we can treat R1 and R2 as
being
in
series
with
each
other:all
of

the
electrons
flowing
through
R1
must
flow
机电控制工程基础

through R2.
换句话说，我们可以认为R1
和
R2
串联，
即通过
R1
的电流一定会
通 过
R2
。

,which
do
not
use
operating
sytems,minimize reliability cincerns with true
parallel
execution
and
deterministic
hardware dedicated to every task.
FPGA
不使用操作系统，减少了对每项任务并
行操 作和确定的硬件分配的依赖性。

l
communication
protocols,for
example,have
specifications
that
can
chang
over
time,and
ASIC-based
interfaces
may
cause
maintenance
and
forward
compatibility challenges.
例如，数字通信
协议规范可能随时改变，
基于
ASIC
的接
口则保持稳定且兼容。

is an acronym for Very high speed
intergrated
circuit(VHSIC)Hardware
Description
Language
which
is
a
communication signals.

programming
Language
that
describes
a
函数的傅里叶表示，即将函数表
logic
cir
cuit
by
function,data
flow
示成正弦和余弦信号的叠加，这种方
behavior,and/or structure.
VHDL
是甚
法已经广泛用于微分方程的解析法和
高速集成电路硬件描述语言 的缩写，它
数值法求解过程以及通信信号的分析
是一种通过函数、数据流和（或）结构
和处理。

描述逻辑电路的可编程语言。

The
Fourier
transform
’
s
utility
lies
in
its

data
flow
model
makes
use
of

ability
to
analyze
a
signal
in
the
time
concurrent
statements
that
are
executed
in
domain
for
its
frequency
content.
The
parallel as soon as data arrives at the input.
transform
works
by
first
translating
a

数据流模式在数据到达输入端的同
function
in
the
time
domain
into
a
事就给出相同的说明。

function
in
the
frequency
domain.
2.
傅里叶分析

The signal can then be analyzed for
Fourier
’
s
epresentation
of

functions
as
a
its
frequency
content
because
the
superposition
of

sines
and
cosines
has
Fourier
coefficients
of
the
become ubiquitous for both the analytic and
transformed function represent the
numerical solution of
differential equations
contribution
of
each
sine
and
and
for
the
analysis
and
treatment
of
cosine
function
at
each
frequency.
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An
inverse
Fourier
transform
dose
just
what
you
’
d
expect,
transform
data
from
the
frequency
domain
into the time domain.

傅里叶变换的效用在于它能够在
时域范围内分析它的频率内容。变换
的第一步是将时域上的函数转换为时
域表示。然后就可以分析信号的频率
内容了。因为 变换函数的傅里叶系数
代表各个正弦和余弦函数在各自对应
频率区间的分配。傅里叶逆变换就会
按你刚才设想的那样，将频域数据转
换为时域的。

The
discrete
Fourier
transform
(DFT)
estimates
the
Fourier
transform of a function
from
a
finite number of
its
sampled
points. The
sampled points are supposed
to
be
typical
of
what the signal looks like at all other times