【关键字】精品
Words and Expressions
integrator n. 积分器amplitude n. 幅值slope n 斜率denominator n. 分母impedance n 阻抗inductor n. 电感capacitor n 电容cascade n. 串联passband n 通带ringing n. 振铃damping n. 阻尼，衰减conjugate adj. 共轭的stage v. 成为
low-pass filters 低通滤波器building block 模块
linear ramp 线性斜坡
log/log coordinates 对数/对数坐标Bode plot 伯德图
transfer function 传递函数complex-frequency variable 复变量complex frequency plane 复平面real component 实部
frequency response 频率响应complex function 复变函数Laplace transform 拉普拉斯变换real part 实部
imaginary part 虚部
angular frequency 角频率frequency response 频率响应
transient response 瞬态响应
decaying-exponential response 衰减指数响应step function input 阶跃（函数）输入
time constant 时间常数
first-order filters 一阶滤波器
second-order low-pass filters 二阶低通滤波器passive circuit 无源电路
active circuit 有源电路
characteristic frequency 特征频率
quality factor n. 品质因子，品质因数circular path 圆弧路径
complex conjugate pairs 共轭复数对switched-capacitor 开关电容
negative-real half of the complex plane 复平面负半平面
Unit 4 Low-pass Filters
First-Order Filters
An integrator (Figure 2. la) is the simplest filter mathematically, and it forms the building block for most modern integrated filters. Consider what we know intuitively about an integrator. If you apply a DC signal at the input (i.e., zero frequency), the output will describe a linear ramp that grows in amplitude until limited by the power supplies. Ignoring that limitation, the response of an integrator at zero frequency is infinite, which means that it has a pole at zero frequency. (A pole exists at any frequency for which the transfer function's value becomes infinite.)（为什么为极点，为什么低通？）
Figure https://www.doczj.com/doc/8b19192851.html, A simple RC integrator
We also know that the integrator's gain diminishes with increasing frequency and that at high frequencies the output voltage becomes virtually zero. Gain is inversely proportional to frequency, so it has a slope of -1 when plotted on log/log coordinates (i.e., -20dB/decade on a Bode plot, Figure 2. 1b).
Figure 2.1 b A Bode plot of a simple integrator
You can easily derive the transfer function as
Where s is the complex-frequency variable and is 1/RC. If we think of s as frequency, this formula confirms the intuitive feeling that gain is inversely proportional to frequency.
The next most complex filter is the simple low-pass RC type (Figure 2. 2a). Its characteristic (transfer function) is
When, the function reduces to , i.e., 1. When s tends to infinity, the function tends to zero, so this is a low-pass filter. When, the denominator is zero and the function's value is infinite, indicating a pole in the complex frequency plane. The magnitude of the transfer function is plotted against s in Figure 2. 2b, where the real component of s () is toward us and the positive imaginary part () is toward the right. The pole at - is evident. Amplitude is shown logarithmically to emphasize the function's form. For both the integrator and the RC low-pass filter, frequency response tends to zero at infinite frequency; that is, there is a zero at. This single zero surrounds the complex plane.
But how does the complex function in s relate to the circuit's response to actual frequencies? When analyzing the response of a circuit to AC signals, we use the expression for impedance of an inductor and for that of a capacitor. When analyzing transient response using Laplace transforms, we use sL and 1/sC for the impedance of these elements. The similarity is apparent immediately. The in AC analysis is in fact the imaginary part of s, which, as mentioned earlier, is composed of a real part and an imaginary part.
If we replace s by in any equation so far, we have the circuit's response to an angular frequency. In the complex plot in Figure 2.2b, and hence along the positive j axis. Thus, the function's value along this axis is the frequency response of the filter. We have sliced the function along the axis and emphasized the RC low-pass filter's frequency-response curve by adding a heavy line for function values along the positive j axis. The more familiar Bode plot (Figure 2.2c) looks different in form only because the frequency is
expressed logarithmically.（根据图翻译这两句话）
Figure 2.2a A simple RC low-pass filter
While the complex frequency's imaginary part () helps describe a response to AC signals, the real part
() helps describe a circuit's transient response. Looking at Figure 2.2b, we can therefore say something about the RC low-pass filter's response as compared to that of the integrator. The low-pass filter's transient response is more stable, because its pole is in the negative-real half of the complex plane. That is, the low-pass filter makes a decaying-exponential response to a step-function input; the integrator makes an infinite response. For the low-pass filter, pole positions further down the axis mean a higher, a shorter time constant, and therefore a quicker transient response. Conversely, a pole closer to the j axis causes a longer transient response.
So far, we have related the mathematical transfer functions of some simple circuits to their associated poles and zeroes in the complex-frequency plane . From these functions, we have derived the circuit ’s frequency response (and hence its Bode plot) and also its transient response. Because both the integrator and the RC filter have only one s in the denominator of their transfer functions, they each have only one pole. That is, they are first-order filters .
Figure 2.2b The complex function of an RC low-pass filter
Figure 2.2c A Bode plot of a low-pass filter
However, as we can see from Figure 2.1b, the first-order filter does not provide a very selective frequency response. To tailor a filter more closely to our needs , we must move on to higher orders. From now on, we will describe the transfer function using f(s) rather than the cumbersome IN OUT V V . Second-Order Low-Pass Filters
A second-order filter has 2s in the denominator and two poles in the complex plane. You can obtain such a response by using inductance and capacitance in a passive circuit or by creating an active circuit of resistors, capacitors, and amplifiers. Consider the passive LC filter in Figure 2.3a, for instance. We can show that its transfer function has the form
and if we define
LC /120=ωand R L Q /0ω=,then where 0ωis the filter's characteristic frequency and Q is the quality factor (lower R means higher Q).
Figure 2.3a An RLC low-pass filter
The poles occur at s values for which the denominator becomes zero; that is,
when 0/2
002=++ωωQ s s . We can solve this equation by remembering that the roots of 02=++c bx ax are given by
In this case, a = 1, b 0ω=, and 20ω=c .The term (ac b 42-) equals ()4/1220-Q ω, so if Q is
less than 0.5 then both roots are real and lie on the negative-real axis. The circuit's behavior is much like that of two first order RC filters in cascade . This case isn't very interesting, so we'll consider only the case where Q > 0.5, which means ()
ac b 42-is negative and the roots are complex.
Figure 2.3b A pole-zero diagram of an RLC low-pass filter
The real part is therefore a b 2/-, which is Q 2/0ω-, and common to both roots. The roots' imaginary parts will be equal and opposite in signs. Calculating the position of the roots in the complex plane, we find that they lie at a distance of
0ωfrom the origin, as shown in Figure 2.3b. Varying 0ω, changes the poles' distance from the origin. Decreasing the Q moves the poles toward each other, whereas increasing the Q moves the poles in a semicircle away from each other and toward the ωj axis. When Q = 0.5, the poles meet at 0ω-on the negative-real axis. In this case, the corresponding circuit is equivalent to two cascaded first-order filters.
Now let's examine the second-order function's frequency response and see how it varies with Q. As before, Figure 2.4a shows the function as a curved surface, depicted in the three-dimensional space formed by the complex plane and a vertical magnitude vector . Q =0.707, and you can see immediately that the response is a low-pass filter.
The effect of increasing the Q is to move the poles in a circular path toward the ωj axis. Figure
2.4b shows the case where Q = 2. Because the poles are closer to the ωj axis, they have a greater effect on the frequency response, causing a peak at the high end of the passband .
Figure 2.4a The complex function of a second-order low-pass filter (Q = 0.707)
Figure 2.4b The complex function of a second-order low-pass filter (Q = 2)
There is also an effect on the filter's transient response. Because the poles' negative-real part is smaller, an input step function will cause ringing at the filter output. Lower values of Q result in less ringing, because the damping is greater. On the other hand, if Q becomes infinite, the poles reach the ωj axis, causing an infinite frequency response (instability and continuous oscillation) at 0ωω=. In the LCR circuit in Figure 2.3a, this condition would be impossible unless R=0. For filters that contain amplifiers, however, the condition is possible and must be considered in the design process.
A second-order filter provides the variables 0ωand Q, which allow us to place poles wherever we want in the complex plane. These poles must, however, occur as complex conjugate pairs , in which the real parts are equal and the imaginary parts have opposite signs. This flexibility in pole placement is a powerful tool and one that makes the second-order stage a useful component in many switched-capacitor filters. As in the first-order case, the second-order low-pass transfer function tends to zero as frequency tends to infinity. The second-order function decreases twice as fast, however, because of the 2
s factor in the denominator. The result is a double zero （零点） at infinity. 低通滤波器
一阶滤波器
从数学公式上讲，积分器（见图2.1a ）是最简单的滤波器；它是构成大多数现代滤波器的基本模块。我们怎么从直观上理解积分器呢？假设在输入端加上一个直流信号（频率为0），那么在输出端将会出现一个线性斜坡信号—其幅度一直增至电源电压。如果不考虑电源电压对输出信号的限制，积分器在零频率上的响应将是无穷大，这意味着它在零频率点上存在一个极点（在任何使传递
函数为无穷大值的频率点上都存在一个极点）。
我们也知道，积分器的增益随频率的增加而减小；在很高频率上的输出电压事实上就是0。增益和频率成反比，因此它在对数坐标系中是一条斜率为-1的直线（见图2.1b ）。
传输函数很容易推导出来（公式略）；其中，s 是复频率变量ωσj +，0ω等于1/RC 。假如把s 当作频率的话，该公式印证了我们有关“增益和频率成反比”的直观推断。
简单低通RC 滤波器（图2.2a ）是一个稍复杂些的滤波器。其传输函数如下：（公式略）。当s 等于0时，函数简化为1；当s 趋近于无穷大时，函数简化为0；因此，这是一个低通滤波器。当s 等于-0ω时，分母为0且函数值为无穷大，这意味着在复频率平面有一个极点。图2.2b 画出了传输函数的幅度和复频率s 的关系，s 的实部σ指向读者，而s 的正虚部ωj 朝右。-0ω处的极点非常明显。为了突出函数的形状，幅度是用对数值显示的。在无穷大频率处，积分器和RC 低通滤波器的频率响应都趋近于0，也就是说在s 等于无穷大处有一个零点。这个零点环绕着复平面。
但是，s 变量复函数和电路的实际频率响应是怎么联系起来的呢？在分析电路对交变信号的响应时，我们用L j ω来表示电感的阻抗，用C j ω1来表示电容的阻抗。在使用拉普拉斯变换分析瞬态响应时，我们用sL 和1/sC 分别表示电感的阻抗和电容的阻抗。这种相似性是显而易见的。实际上，交流分析中的ωj 就是s 的虚部；正如上面提到的那样，s 是由一个实部和一个虚部组成的。
假如将上面任何一个公式中的s 用ωj 替代，就可以得到电路的角频率响应。在图2.2b 中，σ等于0，正j 坐标轴上s 等于ωj 。因此，沿着该坐标轴的函数值就是滤波器的频率响应。我们沿着ωj 轴将函数切割，并且在沿正ωj 坐标轴的函数值处加以粗线，从而突出了RC 低通滤波器的频率响应曲线。因为频率是对数表示的缘故，所以它和人们更熟悉的伯得图在形式上看上去不一样。
复频率的虚部有助于描述电路对交流信号的响应，而其实部有助于描述电路的瞬态响应。从图
2.2b 中可以看出，RC 低通滤波器和积分器之间的一些区别。低通滤波器的瞬态响应更加稳定，因为其极点位于复平面的左半部。即对于阶跃函数输入，滤波器的响应是衰减指数形式的；积分器的响应是无穷大的。对于低通滤波器而言，极点沿σ坐标轴离原点越远，意味着0ω越大，时间常数越短，瞬态响应越快。相反的情况是：极点离ωj 坐标轴越近，瞬态响应越慢。
到目前为止，我们已经阐述了一些简单电路的数学传递函数与其复频率平面上的极、零点之间的关系。从这些函数中，我们可以推导出电路的频率响应（从而可以得到伯得图）及其瞬态响应。因为积分器和RC 滤波器在其传递函数的分母中都仅有一个s ，所以他们仅有一个极点。也就是说，它们都是一阶滤波器。
然而，从图2.2b 中也可以看出：一阶滤波器的频率选择性不是很好。为了得到一个更接近需求的滤波器，我们必须增加阶数。从现在开始，我们将使用()s f 表示传输函数，而不再使用繁琐的IN OUT V V 。
二阶低通滤波器
二阶滤波器的分母中出现了2s ，所以在复平面上就有两个极点。使用电感和电容的无源电路或者包含电阻、电容和放大器的有源电路都具有这样的响应。例如，考虑图2.3a 中的无源LC 滤波器。其传输函数具有如下形式：（公式略），当定义LC /120=ω和R L Q /0ω=之后，该式变为：（公式略），此处的0ω是滤波器的特征频率，而Q 是品质因数（R 越低，Q 越高）。
极点出现在使分母为零的s 值处，即当0/2002=++ωωQ s s 的时候。只要记住0
2=++c bx ax 的根为（公式略），我们可以解出这个方程。
在这个方程中，a 等于1,b 等于Q /0ω，而c 等于20ω。这一项等于()4/1220-Q ω，如果Q 小于0.5，
那么两个根都是实数且位于复实轴上。而电路的性能极似两个一阶滤波器的级联。这种情况不是很有意义，所以我们只考虑5.0>Q 的情况。 这意味着()
ac b 42-小于零，而方程的根都是复数。实部为a b 2/-，等于Q 2/0ω-，这部分对于两个根都是一样的。两根的虚
部互为相反数。计算根在复平面的位置，我们就会发现它们位于距零点0x 处（图2.3b ）。 改变0ω会改变极点距离原点的位置。降低Q 值会将两个极点靠近，而增加Q 值会将极点沿着半圆弧拉开并趋近ωj 轴。当Q=0.5时，两极点在负实轴上的0ω-处汇合。在这种情况下，对应的电路久等效于两个一阶滤波器的级联。
现在，让我们考察一下二阶函数的频率响应及其随Q 变化的情况。和以前一样，图2.4a 展示了在由复平面和垂直幅度向量构成的三维空间中绘制的 函数曲线面。图中Q=0.707，马上就可以看出这是一个低通滤波器的响应。
增大Q 值能将极点沿着圆弧路径移向ωj 轴。图2.4B 展示的是Q=2的情形。由于极点靠近ωj 轴，其对频率响应的影响就越大，这导致在通带高频段出现一个极值。
这对滤波器的瞬态响应也有影响。因为极点的负实部越小，输入阶跃函数就会引起滤波器输出振铃。Q 值越小，振铃越少，因为阻尼更大。另一方面，假如Q 为无限，极点抵达ωj 轴就会引起在0ωω=处的频率响应为无限大（不稳定及持续振荡）。在图2.3a 的LCR 电路中，这种情况是不可能出现的，除非R=0。然而，对于包含放大器的滤波器而言，这种情况是有可能出现的，在设计过程中必须考虑这一点。
二阶滤波器提供了0ω和Q 这两个变量，这就允许我们将极点放置在复平面上任何需要的地方。 然而，这两个极点必须是一对共轭队，二者是不相同而虚部符号相反。极点放置的这种灵活性是一种强大的手段，它使二阶滤波器成为众多开关电容滤波器中一个有用部件。与一阶低通滤波器传输函数一样，随着频率也趋近于无穷，二阶低通滤波器的传输函数趋于零。然而，二阶低通滤波器传输函数的下降速度是一阶低通滤波器传输函数下降速度的两倍；这是分母中出现2
s 因子的缘故。这样，在无穷大处就存在两个零点。
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Words and Expressions integrator n. 积分器amplitude n. 幅值slope n 斜率denominator n. 分母impedance n阻抗inductor n. 电感capacitor n电容cascade n. 串联passband n 通带ringing n. 振铃damping n. 阻尼，衰减conjugate adj. 共轭的stage v. 成为 low-pass filters 低通滤波器building block 模块 linear ramp 线性斜坡 log/log coordinates 对数/对数坐标Bode plot 伯德图 transfer function 传递函数complex-frequency variable 复变量complex frequency plane 复平面real component 实部 frequency response 频率响应complex function 复变函数Laplace transform 拉普拉斯变换real part 实部 imaginary part 虚部 angular frequency 角频率frequency response 频率响应 transient response 瞬态响应 decaying-exponential response 衰减指数响应step function input 阶跃（函数）输入 time constant 时间常数 first-order filters 一阶滤波器 second-order low-pass filters 二阶低通滤波器passive circuit 无源电路 active circuit 有源电路 characteristic frequency 特征频率 quality factor n. 品质因子，品质因数circular path 圆弧路径 complex conjugate pairs 共轭复数对switched-capacitor 开关电容 negative-real half of the complex plane 复平面负半平面
Unit 1 享受幽默——是什么使人开怀？ [1]The joy of laughing at a funny story is universal, probably as old as language itself. But, what is it that makes a story or a joke funny? 1 听了一个有趣的故事会发笑、很开心，古今中外都一样。这一现象或许同语言本身一样悠久。那么，到底是什么东西会使一个故事或笑话让人感到滑稽可笑的呢？ [2] As one who has enjoyed humor since I first recognized it, I've made an attempt to explain and discuss humor with students in such diverse cultures as Latin America and China. I've done some serious thinking about funny stories. It has been a labor of love! 2 我是第一次辨识出幽默便喜欢上它的人，因此我曾试图跟学生议论和探讨幽默。这些学生文化差异很大，有来自拉丁美洲的，也有来自中国的。我还认真地思考过一些滑稽有趣的故事。这么做完全是出于自己的喜好。 [3]Why is it that several students in a class will fall out of their chairs laughing after I tell a joke while the rest of the students look as if I've just read the weather report?[N]Obviously some people are more sensitive to humor than others. And, we recognize that some people tell jokes very well while others struggle to say something funny. We've all heard people say, "I like jokes, but I can't tell one well, and I can never remember them." Some people have a better sense of humor than others just as some people have more musical talent, mathematical talent, etc. than others. A truly funny person has a joke for every occasion, and when one is told, that triggers an entire string of jokes from that person's memory bank. A humorless person is not likely to be the most popular person in a group.It is reasonable to say that the truly humorous individual is not only well liked, but is often the focus of attention in any gathering. 3 为什么听我讲完一个笑话后，班上有些学生会笑得前仰后合，而其他学生看上去就像刚听我读了天气预报一样呢？显然，有些人对幽默比别人更敏感。而且，我们也发现有的人很善于讲笑话，而有的人要想说一点有趣的事却要费好大的劲。我们都听人说过这样的话：“我喜欢笑话，但我讲不好，也总是记不住。”有些人比别人更有幽默感，就像有些人更具有音乐、数学之类的才能一样。一个真正风趣的人在任何场合都有笑话可讲，而且讲了一个笑话，就会从他记忆里引出一连串的笑话。一个缺乏幽默感的人不可能成为一群人中最受欢迎的人。一个真正有幽默感的人不仅受人喜爱，而且在任何聚会上也往往是人们注意的焦点。这么说是有道理的。 [4]Even some animals have a sense of humor. My wife's mother often visited us for extended stays.She normally didn't like dogs, but she fell in love with Blitzen[N]—a female Lab we had, and the relationship was mutual（相互的）. Even when young, Blitzen would tease Grandma by very selectively carrying one of her bedroom slippers into the living room where Grandma sat in her favorite, comfortable chair. Blitzen pranced（蹦来跳去）just beyond the reach of Grandma until Grandma was tempted to leave her chair to get the slipper from Blitzen. When Grandma left her chair, Blitzen would quickly jump into the chair, flashing her Lab smile from sparkling（闪烁的）brown eyes which clearly said, "Aha, I fooled you again." 4 甚至有些动物也具有幽默感。我岳母从前经常来我们家，并能住上很长一段时间。通常她不喜欢狗，但却很喜欢布利茨恩—我们养过的一条拉布拉多母猎犬。而且，她们的这种喜欢是相互的。布利茨恩在很小的时候就常常戏弄外祖母，当外祖母坐在起居室里她最喜欢的那张舒适的椅子上时，布利茨恩就故意把她卧室里的一只拖鞋叼到起居室，并在外祖母刚好够不到的地方蹦来跳去，一直逗到外祖母忍不住站起来去拿那只拖鞋。外祖母从椅子上一起来，布利茨恩就迅速跳上那椅子，从它那闪亮的棕色眼睛里掠过一丝拉布拉多式的微笑，无疑是在说：“啊哈，你又上了我的当。” [5]Typical jokes or humorous stories have a three-part anatomy（结构）that is easily recognized. First is the SETUP (or setting), next is the BODY (or story line), and these are followed by the PUNCH LINE[N](an unexpected or surprise ending) which will make the joke funny if it contains some humor. Usually all three parts are present, and each must be clearly presented. It helps if the story/joke teller uses gestures and language which are well-known to the audience.
1 Hello. My name is Stephen Hawking. Physicist, cosmologist and something of a dreamer. Although I cannot move and I have to speak through a computer, in my mind I am free. Free to explore the universe and ask the big questions, such as: is time travel possible? Can we open a portal to the past or find a shortcut to the future? Can we ultimately use the laws of nature to become masters of time itself? 大家好，我是斯蒂芬-霍金，是物理学家、宇宙学家及梦想家，尽管身体不能活动，只能通过电脑与大家交流，但从内心中我是自由的，自由地探索宇宙，思考以下重大问题：时间旅行是否可行？能否打开一个回到过去的通道，或找到通向未来的捷径？我们最终能否利用自然规律成为掌控时间的主人？ 2 To see how this might be possible, we need to look at time as physicists do - at the fourth dimension. It's not as hard as it sounds. Every attentive schoolchild knows that all physical objects, even me in my chair, exist in three dimensions. Everything has a width and a height and a length. 为了让这一切从虚幻变成现实，我们应以物理学家的角度来重新审视时间——即第四维。这个问题没有听上去那么晦涩难懂。每个好学的孩子都知道，任何物体都以三维形式存在，包括坐在轮椅上的我。一切物体都有宽度、高度和长度。 3 But there is another kind of length, a length in time. While a human may survive for 80 years, the stones at Stonehenge, for instance, have stood around for thousands of years. And the solar system will last for billions of years. Everything has a length in time as well as space. Travelling in time means travelling through this fourth dimension. 此外，还有一种长度——时间的长度。例如，虽然一个人可能活了80岁，但巨石阵的石头却数千年屹立不倒。太阳系的运行将持续数十亿年。一切物体都有时间以及空间的长度。时间旅行意味着我们要经过第四维。 4 To see what that means, let's imagine we're doing a bit of normal, everyday car travel. Drive in a straight line and you're travelling in one dimension. Turn right or left and you add the second dimension. Drive up or down a twisty mountain road and that adds height, so that's travelling in all three dimensions. But how on Earth do we travel in time? How do we find a path through the fourth dimension? 要想搞明白这一点，我们可以想象正在从事一种日常活动，比如开车。开车沿直线行驶，是在一维中旅行。向左转或是向右转，则是二维旅行。驱车上下山路意味着又多增加了高度，所以是在三维空间内。那么我们怎样才能实现时间旅行？怎样才能发现穿越第四维的通道呢？ 5 Let's indulge in a little science fiction for a moment. Time travel movies often feature a vast, energy-hungry machine. The machine creates a path through the fourth dimension, a tunnel through time. A time traveller, a brave, perhaps foolhardy individual, prepared for who knows what, steps into the time tunnel and emerges who knows when. The concept may be far-fetched, and the reality may be very different
外文文献翻译译稿1 卡尔曼滤波的一个典型实例是从一组有限的，包含噪声的，通过对物体位置的观察序列(可能有偏差）预测出物体的位置的坐标及速度。在很多工程应用（如雷达、计算机视觉）中都可以找到它的身影。同时，卡尔曼滤波也是控制理论以及控制系统工程中的一个重要课题。例如，对于雷达来说，人们感兴趣的是其能够跟踪目标.但目标的位置、速度、加速度的测量值往往在任何时候都有噪声。卡尔曼滤波利用目标的动态信息，设法去掉噪声的影响，得到一个关于目标位置的好的估计.这个估计可以是对当前目标位置的估计(滤波),也可以是对于将来位置的估计（预测），也可以是对过去位置的估计（插值或平滑). 命名[编辑] 这种滤波方法以它的发明者鲁道夫。E。卡尔曼(Rudolph E. Kalman）命名，但是根据文献可知实际上Peter Swerling在更早之前就提出了一种类似的算法。 斯坦利。施密特（Stanley Schmidt)首次实现了卡尔曼滤波器。卡尔曼在NASA埃姆斯研究中心访问时,发现他的方法对于解决阿波罗计划的轨道预测很有用，后来阿波罗飞船的导航电脑便使用了这种滤波器。关于这种滤波器的论文由Swerling（1958）、Kalman (1960)与Kalman and Bucy（1961）发表。 目前,卡尔曼滤波已经有很多不同的实现.卡尔曼最初提出的形式现在一般称为简单卡尔曼滤波器。除此以外，还有施密特扩展滤波器、信息滤波器以及很多Bierman, Thornton开发的平方根滤波器的变种.也许最常见的卡尔曼滤波器是锁相环，它在收音机、计算机和几乎任何视频或通讯设备中广泛存在。 以下的讨论需要线性代数以及概率论的一般知识。 卡尔曼滤波建立在线性代数和隐马尔可夫模型(hidden Markov model）上.其基本动态系统可以用一个马尔可夫链表示，该马尔可夫链建立在一个被高斯噪声（即正态分布的噪声）干扰的线性算子上的。系统的状态可以用一个元素为实数的向量表示.随着离散时间的每一个增加，这个线性算子就会作用在当前状态上，产生一个新的状态,并也会带入一些噪声,同时系统的一些已知的控制器的控制信息也会被加入。同时，另一个受噪声干扰的线性算子产生出这些隐含状态的可见输出。 卡尔曼滤波是一种递归的估计，即只要获知上一时刻状态的估计值以及当前状态的观测值就可以计算出当前状态的估计值,因此不需要记录观测或者估计的历史信息.卡尔曼滤波器
They say that pride comes before a fall. In the case of both Napoleon and Hitler, the many victories they enjoyed led them to believe that anything was possible, that nothing could stand in their way. Russia's icy defender was to prove them wrong. 人道是骄兵必败。就拿拿破仑和希特勒两人来说吧，他们所向披靡，便以为自己战无不胜，不可阻挡。但俄罗斯的冰雪卫士证明他们错了。 The Icy Defender Nila B. Smith 1 In 1812, Napoleon Bonaparte, Emperor of the French, led his Grand Army into Russia. He was prepared for the fierce resistance of the Russian people defending their homeland. He was prepared for the long march across Russian soil to Moscow, the capital city. But he was not prepared for the devastating enemy that met him in Moscow -- the raw, bitter, bleak Russian winter. 冰雪卫士 奈拉·B·史密斯 1812年，法国皇帝拿破仑·波拿巴率大军入侵俄罗斯。他准备好俄罗斯人民会为保卫祖国而奋勇抵抗。他准备好在俄罗斯广袤的国土上要经过长途跋涉才能进军首都莫斯科。但他没有料到在莫斯科他会遭遇劲敌—俄罗斯阴冷凄苦的寒冬。 2 In 1941, Adolf Hitler, leader of Nazi Germany, launched an attack against the Soviet Union, as Russia then was called. Hitler's military might was unequaled. His war machine had mowed down resistance in most of Europe. Hitler expected a short campaign but, like Napoleon before him, was taught a painful lesson. The Russian winter again came to the aid of the Soviet soldiers. 1941年，纳粹德国元首阿道夫·希特勒进攻当时被称作苏联的俄罗斯。希特勒的军事实力堪称无敌。他的战争机器扫除了欧洲绝大部分地区的抵抗。希特勒希望速战速决，但是，就像在他之前的拿破仑一样，他得到的是痛苦的教训。仍是俄罗斯的冬天助了苏维埃士兵一臂之力。 Napoleon's Campaign 3 In the spring of 1812, Napoleon assembled an army of six hundred thousand men on the borders of Russia. The soldiers were well trained, efficient, and well equipped. This military force was called the Grand Army. Napoleon, confident of a quick victory, predicted the conquest of Russia in five weeks. 拿破仑发起的战役 1812年春，拿破仑在俄国边境屯兵60万。这些士兵受过良好训练，作战力强，装备精良。这支军队被称为大军。拿破仑对马到成功充满自信，预言要在5个星期内攻下俄国。 4 Shortly afterwards, Napoleon's army crossed the Neman River into Russia. The quick, decisive victory that Napoleon expected never happened. To his surprise, the Russians refused to stand and fight. Instead, they retreated eastward, burning their crops and homes as they went. The Grand Army followed, but its advance march soon became bogged down by slow-moving supply lines. 不久，拿破仑的大军渡过涅曼河进入俄国。拿破仑期盼着的速决速胜迟迟没有发生。令他吃惊的是，俄国人并不奋起抵抗。相反，他们一路东撤，沿途焚毁庄稼和民居。大军紧追不舍，但它的长驱直入很快由于粮草运输缓慢而停顿下来。 5 In August, the French and Russian armies engaged at Smolensk, in a battle that left over ten thousand dead on each side. Yet, the Russians were again able to retreat farther into Russian
《专业英语（制药工程）》
【科技英语的常用句型和翻译技巧】 一、概述 1. 翻译的要求The Criteria of Translation：信、雅、达 2. 科技英语词汇（上节课已经介绍） 3. 科技英语句子的特点 二、科技英语常用句型及翻译 1. 被动语态 1）被动语态的常用原因 常用被动语态主要见于以下几个方面： ①不必或无法说出主动者 For a long time aluminum has been thought as an effective material for preventing metal corrosion. 长期以来，铝被当作一种有效的防止金属腐蚀的材料。 ►The book has already been translated into many languages. ②强调行为对象，而非行为者，将行为对象作为句子的主语 Three machines can be controlled by a single operation. 三台机器能由一个操作者操纵。 ►The work must be finished at once. ③为了更好的联系上下文 ►They are going to build a library here next year. It is going to be build beside the classroom building. 2）被动语句的翻译方法 （1）仍译为被动句 最常见的是在谓语前加上助词“被”，也可使用“受到，遭到，得到，叫，称，让，给，加以，为……所”等句式。偶尔也可不加任何词直接译出。 We remember how air can be made into a liquid. If the liquid is warmed again, it “boiled”and turns back into a gas. 我们记得是如何把空气制成液体的。如果给这种液体重新加热，它“沸腾汽化”，就又还原成气体。 ►Every thing is built up of atoms. ►The process by which energy is changed from one form into another is called the transformation of energy. Water is usually considered as being a compound of two elements. （2）译为主动句，中国汉语的习惯 ①译成无主语的主动句
Old Father Time Becomes a Terror Richard Tomkins 1 Once upon a time, technology, we thought，would make our lives easier. Machines were expected to do our work for us，leaving us with ever—increasing quantities of time to waste away on idleness and pleasure. 时间老人成了可怕的老人 理查德·汤姆金斯 从前，我们以为技术发展会使我们的生活变得更安逸.那时我们觉得机器会替代我们工作，我们则有越来越多的时间休闲娱乐。 2 But instead of liberating us，technology has enslaved us. Innovations are occurring at a bewildering rate: as many now arrive in a year as once arrived in a millennium. And as each invention arrives, it eats further into our time。 但技术发展没有把我们解放出来，而是使我们成为奴隶。新技术纷至沓来,令人目不暇接：一年涌现的技术创新相当于以前一千年。而每一项新发明问世，就进一步吞噬我们的光阴. 3 The motorcar，for example, promised unimaginable levels of personal mobility. But now, traffic in cities moves more slowly than it did in the days of the horse-drawn carriage，and we waste our lives stuck in traffic jams. 比如，汽车曾使我们希望个人出行会方便得让人难以想象。可如今，城市车辆运行得比马车时代还要慢，我们因交通堵塞而困在车内，徒然浪费生命。 4 The aircraft promised new horizons, too。The trouble is, it delivered them. Its very existence created a demand for time-consuming journeys that we would never previously have dreamed of undertaking -— the transatlantic shopping expedition, for example，or the trip to a convention on the other side of the world. 飞机也曾有可能为我们拓展新天地.问题是，飞机提供了新的天地。其存在本身产生了对耗时的长途旅行的需求，这种旅行，如越洋购物，或远道前往地球的另一半参加会议，以前我们是根本无法想象的。 5 In most cases, technology has not saved time, but enabled us to do more things。In the home，washing machines promised to free women from having to toil over the laundry. In reality, they encouraged us to change our clothes daily instead of weekly，creating seven times as much washing and ironing. Similarly, the weekly bath has been replaced by the daily shower, multiplying the hours spent on personal grooming。在大多数情况下，技术发展并未节省时间，而是使我们得以做更多的事。在家里，洗衣机可望使妇女摆脱繁重的洗衣劳作。但事实上，它们促使我们每天,而不是每星期换一次衣服，这就使熨洗衣物的工作量变成原来的7倍。同样地，每周一次的沐浴为每日一次的淋浴所代替，使得用于个人穿着打扮的时间大大增加. 6 Meanwhile，technology has not only allowed work to spread into our leisure time -- the laptop—on-the-beach syndrome -— but added the new burden of dealing with faxes, e-mails and voicemails. It has also provided us with the opportunity to spend hours fixing software glitches on our personal computers or filling our heads with useless information from the Internet。 与此同时，技术发展不仅听任工作侵入我们的闲暇时间――带着便携式电脑去海滩综合
Unit 4 When we abuse animals, we debase ourselves 人类虐待动物就是在贬损自己 Moving a cow by chaining it to a tractor and dragging it by its leg says a lot about how we perceive and value animals. When the Humane Society video that showed this and other brutal slaughterhouse treatment made the rounds on the Internet a few weeks ago, it caused public shock and led to a federal investigation. But there's a deeper lesson that all of us – whether or not we eat meat – need to take to heart: we degrade ourselves when we degrade animals. 将一头牛锁在一辆拖拉机上然后拖动很好地表明了我们对动物的看法和感受。当人道协会的这个展现了这样场面等其它屠宰场里残忍对待的录像片在数周前网上散布后它引起了公众的震惊，导致联邦政府开展调查。但是对我们所有人来说这还是一个更为深刻的教训--不论我们是否吃肉--应该铭刻在心中：在贬低动物的同时我们在贬低自己。 Much as bullies demoralize themselves when they dominate or ride roughshod over those who are meek, vulnerable, or defenseless, it should be obvious that human beings are the ones demoralized by the commission of inhumane acts. 正如那些欺负者们当控制那些温顺、脆弱或没有抵抗力的人们或骑在他们头上是在将自己的道德败坏一样去进行那些残忍的虐待动物的活动中人类的道德也被这种非人道的行为所败坏。 Over the years, many have been caught up in the debate over what is, or is not, man's obligation to animals. But the debate is transcended by the growing realization that neither our civilization nor our planet will survive unless human beings grow richer in moral qualities like mercy, kindness, compassion, and temperance. 长期以来让许多人纠缠不清的是到底哪些是哪些不是人类对动物的义务。不过人们越来越认识到除非人类在怜悯、善良、同情和节制上提高否则我们的文明或地球都将不复存在。这个观点已经超略了前面的争论。 Yet in order to establish a platform for speaking out against cruel and painful laboratory experiments and slaughtering techniques, animal rights advocates are often asked to prove that animals have a moral sense and can feel physical and emotional pain. 然而为了建立一个疾呼反对残忍和痛苦的试验及屠宰方式的平台，动物权利提倡者往往被要求证明动物有道德感；能感到身体或感情的痛苦。 But even if animals could be proved amoral and immune to pain, human beings would have no basis for even careless treatment of them. Most of us were taught as children to take good care of inanimate objects, even though they feel no pain and have no moral sense. We are taught to treat fine books with virtual reverence. We are taught that it is actually a crime to vandalize buildings, cars, and other inanimate objects.
Automation and Controlling sensor 传感器 sufficient and necessary condition 充要条件 dry friction 静摩擦 follower 跟随器，输出放大器，从动轮，跟踪装置 integral 积分 duty 工作状态 FM(frequency modulation ) 调频 Geometry 几何(学) autopilot 自动驾驶仪 forced response 强迫响应 performance index 性能指数 performance specification 性能指标 polar plot 极坐标图 trial and error 试探法 Bar Code 条形码 Bill of Materials (BOM) 物料清单 CAD (Computer Aided Design) 计算机辅助设计 CAM (Computer Aided Manufacturing) 计算机辅助制造 Computer Integrated Manufacturing (CIM) 计算机集成制造 CMOS (Complimentary Metal-Oxide-Semiconductor) n. 互补金属氧化物半导体——一种应用于大规模集成电路 芯片制造的原料）是微机主板上的一块可读写的RAM芯片，用来保 存当前系统的硬件配置和用户对某些参数的设定。 ControlNet 控制网，一种高速串行通信系统，适用于需要进行实时应用信息交换 的设备之间的通讯。 conveyor 传送带 DAC (Digital-to-Analog Converter) 数字模拟信号转换器 Data Acquisition 数据采集 Fiber Optics 光纤 Fieldbus 现场总线 Ethernet 以太网 GUI (Graphical User Interface) 图形用户界面 programming language 程序设计语言 program debugger 程序调试器 direct current dynamo 直流发电机 kinetic energy 动能 automatization 自动化 human-simulating-intelligent control 仿人工智能控制 reference frame 参考系 servo 伺服机构 extrusion 挤压 billet 胚料 dual 对偶的，二元的，二体的，双的 actuator 激励源（如电流源、电压源）；致动器 AS-I (Actuator-Sensor Interface) 执行器传感器接口 Analog Input Module 模拟信号输入模块 Analog Output Module 模拟信号输出模块 Brushless Servomotor 无电刷伺服电机 Crossdocking 直接转运，一项使产品组合顺利进行的作业。在作业中，来自不同供 货商的产品聚集到流通仓库，但这些货物并不是储存起来供以后进行 分拣，而是直接穿过仓库，载入正在等待的货车，然后送给特定的顾客。couple vt.耦合,匹配
科技英语原文及简单翻译 How ASIMO Works Introduction to How ASIMO Works Want a robot to cook your dinner, do your homework, clean your house, or get your groceries? Robots already do a lot of the jobs that we humans don't want to do, can't do, or simply can't do as well as our robotic counterparts. Honda engineers have been busy creating the ASIMO robot for more than 20 years. In this article, we'll find out what makes ASIMO the most advanced humanoid robot to date. The Honda Motor Company developed ASIMO, which stands for Advanced Step in Innovative Mobility, and is the most advanced humanoid robot in the world. According to the ASIMO Web site, ASIMO is the first humanoid robot in the world that can walk independently and climb stairs. Rather than building a robot that would be another toy, Honda wanted to create a robot that would be a helper for people -- a robot to help around the house, help the elderly, or help someone confined to a wheelchair or bed. ASIMO is 4 feet 3 inches (1.3 meters) high, This allows ASIMO to do the jobs it was created to do without being too big and menacing. ASIMO's Motion: Walk Like a Human Honda researchers began by studying the legs of insects, mammals, and the motion of a mountain climber with prosthetic legs to better understand the physiology and all of the things that take place when we walk -- particularly in the joints. For example, the fact that we shift our weight using our bodies and especially our arms in