通信与电子信息工程专业英语第1单元TEXT_A&B聂敏(专业翻译版)
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Unit 1
Basics of Communication
A
Text
A Mathematical Theory of Communication
Unit 1
原文:The recent development of various methods of modulation such as PCM and PPM which exchange bandwidth for signal-tonoise ratio has intensified the interest in a general theory of communication.
Unit 1
原文:One feels,for example,that two punched cards should have twice the capacity of one for information storage, and two identical channels twice the capacity of one for transmitting information. 译文:这是一种感觉，例如，两张穿孔卡片比一张 具有有两倍信息贮存量，以及两个单一信道比起 单信道具有两倍的传输信息容量。
Unit 1
原文:The system must be designed to operate for each possible selection, not just the one which will actually be chosen since this is unknown at the time of design. 译文:系统必须被设计成为每个可能的选择进行运 行，而不仅仅是那个实际上将被抽中的，因为这 在设计时是未知的。
译文:在本学科，Nyquist和Hartley的重要论 文中包含了这种理论的基础。
Unit 1
原文:In this paper we will extend the theory to include a number of new factor, in particular the effect of noise in the channel, and the savings possible due to the statistical structure of the original message and due to the nature of the final destination of information. 译文:在本文中，我们将这些理论进行扩展，包括 许多新的因素，尤其是信道中噪声的影响，以及 可能由于原始信息的统计结构和信宿的特性所导 致的信息存储。
UnLeabharlann Baidut 1
原文:A device with two stable positions, such as a relay or a flip-flop circuit, can store one bit of information. N such devices can store N bits, since the total number of possible states is 2 Nand log2 2 N . N 译文:具有两个稳定状态的设备能储存一比特信息， 如一个继电器或一个触发电路。N个这样的设备 能储存N比特信息，是由于所有可能状态的数量 是 2 N 个并且 log2 2 N N 。
Unit 1
原文:3.It is mathematically more suitable. Many of the limiting operations are simple in terms of the logarithm but would require clumsy restatement in terms of the number of possibilities. 译文:3.它在数学上更合适。许多受限操作在对数 上是简单的，然而是数的概率需要笨拙的描述。
Unit 1
原文:These semantic aspects of communication are irrelevant to the engineering problem. A significant aspect is that the actual message is one selected from a set of possible messages. 译文:这些通信的语义方面与工程问题不相干。一 个重要的方面是那个实际的消息是从一组可能的 消息中选出来的。
log2 M log10 M / log10 2 3.32log10 M
（1.1）
Unit 1
原文:A decimal digit is about bits. A digit wheel on a desk computing machine has ten stable positions and therefore has a storage capacity of one decimal digit.
Unit 1
原文:The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point.
Unit 1
原文: If the base 10 is used, the units may be called decimal digits. Since log2 M log10 M / log10 2 3.32log10 M （1.1） 译文:如果以10为底产生的单元可以被称为十进 制数字。因为
Unit 1
原文:The choice of a logarithmic base corresponds to the choice of a unit for measuring information. If the base 2 is used, the resulting units may be called binary digits, or more briefly bits, a word suggested by J.W.Tukey. 译文:对数底的选择对应测量信息单位的选择。如 果以2为底，产生的位将称为二进制数字，或更简 要地叫比特，它是由J.W.Tukey建议的词。
Unit 1
原文:The logarithmic measure is more convenient for various reasons: 1.It is practically more useful. Parameters of engineering importance such as time, bandwidth, the number of relays,etc.,tend to vary linearly with the logarithm of the number of possibilities. 译文:对数度量非常方便，理由如下： 1.对数度量在实践中应用广泛。工程的重要参数 随数据概率的对数而线性改变。 如时间、带宽、 继电器数，等等。
Unit 1
原文:As was pointed out by Hartley the most natural choice is the logarithmic function.
译文:如Hartley所指出的，最自然的选择是个对 数函数。
Unit 1
原文: Although this definition must be generalized considerably when we consider the influence of the statistics of the message and when we have a continuous range of messages, we will in all cases use an essentially logarithmic measure. 译文:当考虑到这个信息统计的改变并且已知信息 的连续范围，尽管这个定义必须相当广义，但不 论什么情况下本质上我们都将使用对数测量。
Unit 1
原文:2. It is nearer to our intuitive feeling as to the proper measure. This is closely related to (1) since we intuitively measures entities by linear comparison with common standards. 译文:2.对数更接近我们本身的直观感受。这与 （1）紧密相关，由于相比于通用标准我们是线性 直观地测量实体对象。
Unit 1
原文:If the number of messages in the set is finite then this number or any monotonic function of the number can be regarded as a measure of the information produced when one message is chosen from the set, all choices being equally like. 译文:如果集合中信息的数量是有限的，那么当一 个信息被从所有的选择是等概的集合中抽出时， 这个数或这个数的任何单调函数可被认为是信息 的度量。
译文:通信的基本问题是如何在一点精确或近似的 再生来自另一点的信息。
Unit 1
原文: Frequently the messages have meaning, that is they refer to or are correlated according to some system with certain physical or conceptual entities. 译文:信息通常有具体含义，按照一定的物理或概 念实体，其含义与这些系统相互关联。
3 1 3
译文:一个十进制数大约3.32比特。一个台式计 算机器的位字轮有十个稳定状态，因此它有一个 十进制数的储存容量。
Unit 1
原文: In analytical work where integration and differentiation are involved the base e is sometimes useful. The resulting units of information will be called natural units. Change from the base a to base b merely requires multiplication by logb a . 译文:在微积分的分析工作中以e为底有时是有用 的。信息位被称为自然数。从以a为底变到以b为 底仅仅只要乘以 logb a 。
译文:各种调制方法，如PCM和PPM，能够完成 带宽与信噪比的交换，它们的发展增强了通信理 论的重要性。
Unit 1
原文:A basis for such a theory is contained in the important papers of Nyquist and Hartley on the subject.
Unit 1
原文:For example, adding one relay to a group doubles the number of possible states of the relays. It adds 1 to the base 2 logarithm of this number. Doubling the time roughly squares the number of possible messages, or doubles the logarithm, etc. 译文:例如，加一个继电器到一个组中会使继电器 组的可能状态的数量翻倍。因为增加了1到这个以 2为底的数的对数。时间翻倍大约是信息概率的平 方，或对数翻倍，等等。
Basics of Communication
A
Text
A Mathematical Theory of Communication
Unit 1
原文:The recent development of various methods of modulation such as PCM and PPM which exchange bandwidth for signal-tonoise ratio has intensified the interest in a general theory of communication.
Unit 1
原文:One feels,for example,that two punched cards should have twice the capacity of one for information storage, and two identical channels twice the capacity of one for transmitting information. 译文:这是一种感觉，例如，两张穿孔卡片比一张 具有有两倍信息贮存量，以及两个单一信道比起 单信道具有两倍的传输信息容量。
Unit 1
原文:The system must be designed to operate for each possible selection, not just the one which will actually be chosen since this is unknown at the time of design. 译文:系统必须被设计成为每个可能的选择进行运 行，而不仅仅是那个实际上将被抽中的，因为这 在设计时是未知的。
译文:在本学科，Nyquist和Hartley的重要论 文中包含了这种理论的基础。
Unit 1
原文:In this paper we will extend the theory to include a number of new factor, in particular the effect of noise in the channel, and the savings possible due to the statistical structure of the original message and due to the nature of the final destination of information. 译文:在本文中，我们将这些理论进行扩展，包括 许多新的因素，尤其是信道中噪声的影响，以及 可能由于原始信息的统计结构和信宿的特性所导 致的信息存储。
UnLeabharlann Baidut 1
原文:A device with two stable positions, such as a relay or a flip-flop circuit, can store one bit of information. N such devices can store N bits, since the total number of possible states is 2 Nand log2 2 N . N 译文:具有两个稳定状态的设备能储存一比特信息， 如一个继电器或一个触发电路。N个这样的设备 能储存N比特信息，是由于所有可能状态的数量 是 2 N 个并且 log2 2 N N 。
Unit 1
原文:3.It is mathematically more suitable. Many of the limiting operations are simple in terms of the logarithm but would require clumsy restatement in terms of the number of possibilities. 译文:3.它在数学上更合适。许多受限操作在对数 上是简单的，然而是数的概率需要笨拙的描述。
Unit 1
原文:These semantic aspects of communication are irrelevant to the engineering problem. A significant aspect is that the actual message is one selected from a set of possible messages. 译文:这些通信的语义方面与工程问题不相干。一 个重要的方面是那个实际的消息是从一组可能的 消息中选出来的。
log2 M log10 M / log10 2 3.32log10 M
（1.1）
Unit 1
原文:A decimal digit is about bits. A digit wheel on a desk computing machine has ten stable positions and therefore has a storage capacity of one decimal digit.
Unit 1
原文:The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point.
Unit 1
原文: If the base 10 is used, the units may be called decimal digits. Since log2 M log10 M / log10 2 3.32log10 M （1.1） 译文:如果以10为底产生的单元可以被称为十进 制数字。因为
Unit 1
原文:The choice of a logarithmic base corresponds to the choice of a unit for measuring information. If the base 2 is used, the resulting units may be called binary digits, or more briefly bits, a word suggested by J.W.Tukey. 译文:对数底的选择对应测量信息单位的选择。如 果以2为底，产生的位将称为二进制数字，或更简 要地叫比特，它是由J.W.Tukey建议的词。
Unit 1
原文:The logarithmic measure is more convenient for various reasons: 1.It is practically more useful. Parameters of engineering importance such as time, bandwidth, the number of relays,etc.,tend to vary linearly with the logarithm of the number of possibilities. 译文:对数度量非常方便，理由如下： 1.对数度量在实践中应用广泛。工程的重要参数 随数据概率的对数而线性改变。 如时间、带宽、 继电器数，等等。
Unit 1
原文:As was pointed out by Hartley the most natural choice is the logarithmic function.
译文:如Hartley所指出的，最自然的选择是个对 数函数。
Unit 1
原文: Although this definition must be generalized considerably when we consider the influence of the statistics of the message and when we have a continuous range of messages, we will in all cases use an essentially logarithmic measure. 译文:当考虑到这个信息统计的改变并且已知信息 的连续范围，尽管这个定义必须相当广义，但不 论什么情况下本质上我们都将使用对数测量。
Unit 1
原文:2. It is nearer to our intuitive feeling as to the proper measure. This is closely related to (1) since we intuitively measures entities by linear comparison with common standards. 译文:2.对数更接近我们本身的直观感受。这与 （1）紧密相关，由于相比于通用标准我们是线性 直观地测量实体对象。
Unit 1
原文:If the number of messages in the set is finite then this number or any monotonic function of the number can be regarded as a measure of the information produced when one message is chosen from the set, all choices being equally like. 译文:如果集合中信息的数量是有限的，那么当一 个信息被从所有的选择是等概的集合中抽出时， 这个数或这个数的任何单调函数可被认为是信息 的度量。
译文:通信的基本问题是如何在一点精确或近似的 再生来自另一点的信息。
Unit 1
原文: Frequently the messages have meaning, that is they refer to or are correlated according to some system with certain physical or conceptual entities. 译文:信息通常有具体含义，按照一定的物理或概 念实体，其含义与这些系统相互关联。
3 1 3
译文:一个十进制数大约3.32比特。一个台式计 算机器的位字轮有十个稳定状态，因此它有一个 十进制数的储存容量。
Unit 1
原文: In analytical work where integration and differentiation are involved the base e is sometimes useful. The resulting units of information will be called natural units. Change from the base a to base b merely requires multiplication by logb a . 译文:在微积分的分析工作中以e为底有时是有用 的。信息位被称为自然数。从以a为底变到以b为 底仅仅只要乘以 logb a 。
译文:各种调制方法，如PCM和PPM，能够完成 带宽与信噪比的交换，它们的发展增强了通信理 论的重要性。
Unit 1
原文:A basis for such a theory is contained in the important papers of Nyquist and Hartley on the subject.
Unit 1
原文:For example, adding one relay to a group doubles the number of possible states of the relays. It adds 1 to the base 2 logarithm of this number. Doubling the time roughly squares the number of possible messages, or doubles the logarithm, etc. 译文:例如，加一个继电器到一个组中会使继电器 组的可能状态的数量翻倍。因为增加了1到这个以 2为底的数的对数。时间翻倍大约是信息概率的平 方，或对数翻倍，等等。