分句自己整理的课本句子.docx

1、分句自己整理的课本句子课件提示一页一课 +课本提示的句子+作业的句子（基于本学期课文的）A transistor is a device that conducts a variable amount of electricity through it, depending on how much electricity is input to it. In other words, it is a digital switch. However, unlike the vacuum tube , it is solid state .晶体管是一种依据输入电量大小而传导可变电量的器件。换言之，

2、晶体管是一种数字开关。然而，和真空管不同，晶体管是“固态”的。 Solid state means that it doesnt change its physical form as it switches. There are no moving parts in a transistor.“固态”的意思是当晶体管切换状态时，它的物理形式不发生变化。晶体管中不存在可以移动的部分 。Compared to the vacuum tube , transistors were much smaller, faster, and cheaper to manufacture. They were

3、 also far more reliable and used much less power. 和真空管相比，晶体管尺寸小得多，速度快得多，生产成本低得多，性能更加可靠，功耗也少得多。 While most materials either insulate from electrical flow (air, glass, wood) or conduct electricity readily (metals, water), there are some that only conduct electricity a small amount, or only under certa

4、in conditions. These are called semiconductors.大多数材料要么对电流绝缘（如空气、玻璃、木头），要么很容易传导电流（如金属、水溶液），但也有一些材料只传导少量电流，或者只在特定条件下传导电流。这些材料被称作半导体。The most commonly used semiconductor is of course silicon. 最常用的半导体材料当然是硅了。Miniaturization means the reduction in size of components and circuits for increasing package de

5、nsity and reducing power dissipation and signal propagation delays.微型化是指减少元件和电路的几何尺寸, 从而增加封装密度、降低功耗、减少信号传播延迟。The integrated circuit is a group of transistors manufactured from a single piece of material and connected together internally, without extra wiring . Integrated circuits are also called ICs

6、 or chips. 集成电路就是一组用单片材料制造的，内部互联的（无外部连线）晶体管。集成电路也叫IC或者芯片。A flip-flop is basically a bi-state circuit in which either a 0 or 1 state can resides. Because of its simplicity, the flip-flop is extremely fast. As a basic element, the flip-flop is used in digital circuits and ICs. A flip-flop will lose it

7、s state when the supply voltage is removed. Therefore, it is volatile. 触发器是一种存储“0”或“1”的双态电路。由于触发器结构简单，所以其速度极快。触发器是数字电路和集成电路中的基本部件。由于电源电压去掉后，触发器原有的状态就失去了，因此它是“易失的”。 A register is a set of flip-flops in parallel. Typically a register is 8,16,32 or 64 bits wide. Often a register is used to hold data, a

8、ddress pointers, etc. A register is volatile and very fast just like the flip-flop.寄存器是一组并行触发器。寄存器的典型数据宽度为8位、16位、32位或者64位。寄存器常用于保存数据、地址指针等。和触发器一样，寄存器也是“易失”的，而且速度很快。SRAM: Static Random Access MemoryAn SRAM is an array of addressable flip-flops. The array can be configured as such that the data comes

9、out in single bit, 4-bit, 8bit, and etc. format. SRAM is simple, fast and volatile just like the flip-flop, its basic memory cell.静态随机存取存储器( SRAM)是一种可寻址的触发器阵列。该阵列可配置成1位、4位、8位等数据格式。它和它的基本存储单元触发器一样：结构简单、存取速度快、具有易失的特点。 DRAM：Dynamic Random Access MemoryThe word dynamic indicates that the data is not hel

10、d in a flip-flop but rather in a storage cell. The data in a storage cell must be refreshed (read out and re-written) regularly because of leakage. 动态随机存取存储器 ：“动态”这个词意味着数据不是保存在触发器当中，而是保存在一个存储单元中。由于存在泄漏，所以保存在存储单元中的数据必须定期更新（读出并重新写入）。ROM: Read Only MemoryROMs are also called mask-ROMs or mask programme

11、d ROMs. This is because a ROM needs to be programmed by setting its cells to either 0 or 1 at the time of manufacture. 只读存储器：也叫做掩模ROM或者掩模编程ROM。这是因为在制造时就需要通过将存储单元置0或置1对其进行编程。 EEPROM：Electrically Erasable Programmable ROMThis means that the chip can be programmed like an EPROM, but can be erased elect

12、rically. As a result, no UV source is required. EEPROM是指该类芯片可以像EPROM一样可编程，但使用的是电擦除的方法。这样，就不需要紫外线信号源了。 Ferroelectric is pertaining to a phenomenon exhibited by certain materials in which the material is polarized in one direction or the other, or reversed in direction by the application of a positive

13、 or negative electric field of magnitude greater than a certain amount. The material retains the electric polarization unless it is disturbed.某些材料表现出的一种现象。当在这种材料上施加超过特定强度的电场时,该材料就在一个方向上极化或改变原极化的方向。只要不受干扰, 这种材料就一直保持其极化状态。A technique where the microprocessor fetches the next instruction before complet

14、ing execution of the previous instruction, in order to increase processing speed.）流水线是一种在前一条指令全部执行完之前就开始取下一条指令，以提高处理速度的技术。RAM stands for random-access memory. RAM contains bytes of information, and the microprocessor can read or write to those bytes depending on whether the RD or WR line is signaled

15、. One problem with todays RAM chips is that they forget everything once the power goes off. That is why the computer needs ROM. RAM是随机存取存储器。RAM中包含着以字节为单位的信息，微处理器能够依据RD/WR信号哪个有效来决定字节的读/写。当前RAM芯片的一个问题是：掉电后，所有保存在RAM上的内容全部丢失。这就是计算机需要ROM的原因。ROM stands for read-only memory. A ROM chip is programmed with a

16、 permanent collection of pre-set bytes. The address bus tells the ROM chip which byte to get and place on the data bus. When the RD line changes state, the ROM chip presents the selected byte onto the data bus. ROM是只读存储器。ROM芯片是用一组永久的预设字节进行编程得到的。地址总线告知ROM芯片要将哪个字节取出并置于数据总线上。当RD信号线改变状态时，ROM芯片将选中的字节输出到数

17、据总线上。This is called negative feedback, and it is the underlying operating principle for all modern day op amps. 这个方案被称为“负反馈”，它是现代运算放大器的基本工作原理。 In 1945 H. W. Bode presented a system for analyzing the stability of feedback systems by using graphical methods. 1945年，伯德提出了一套用来分析反馈系统稳定性的图形化方法。Bode present

18、ed a log technique that transformed the intensely mathematical process of calculating a feedback systems stability into graphical analysis that was simple and perceptive. 伯德提出了一种对数方法，将分析反馈系统稳定性的数学过程转换为容易的、好理解的图形化分析。 Passive components had much better drift characteristics than active components had,

19、 thus if an amplifiers gain could be made dependent on passive components, the problem would be solved. 无源器件比有源器件具有好得多的漂移特性；假如能使得放大器增益仅由无源器件决定的话，那么这个问题就会解决。 The designers problem is how to rapidly select the correct circuit/op amp combination and then, how to calculate the passive component values t

20、hat yield the desired transfer function in the circuit. 设计者需要解决的问题是：（1）怎样迅速选择正确的电路（运放组合）；（2）怎样计算出能产生期望电路传输函数的无源元件值。As digital applications increase, analog applications also increase because the predominant supply of data and interface applications are in the real world, and the real world is an ana

21、log world. 随着数字应用的增加，模拟应用也会增加；因为大量的数据接口应用是在现实世界中，而现实世界是一个模拟的世界。 There has been a never-ending series of new op amps released each year since then, and their performance and reliability has improved to the point where present day op amps can be used for analog applications by anybody .此后，新型运放就不断出现；今天

22、，运放的功能和可靠性已经提高到了这种程度任何人都能在模拟应用中使用它。 The flash converter operates by simultaneously presenting the input signal to a bank of 2N1 comparators, whose reference voltages are set by a resistor chain to exactly correspond to all of the possible sample levels, which can be represented by the converter 闪式AD

23、C将输入信号同时置于一列（2N1）个比较器之前，而比较器的参考电压是由一组电阻设定的，这些参考电压精确对应于转换器代表的所有可能的采样电压值。 For large numbers of bits (e.g. 14 bits), the number of resistors needed (2N1) becomes prohibitively large for most practical applications. Also, the power consumption is considerably higher than some of the slightly slower and

24、more exotic solutions.对于多数实际应用而言，当位数较多时（如大于14位），所需的电阻数目就太大了。和那些速度稍慢、不常见的模数转换方案相比，闪式ADC的功耗明显要高得多。 In fact, there are many tens of ADC methods in use, Successive Approximation, Multipass, Interpolating, Subranging, Bit-Per-Stage, to name but a few of the flavors, each potentially having some benefit i

25、n performance over its rivals. 实际上，目前使用的模数转换方法有几十种。逐次逼近法、多通道法、插值法、子区法和逐位处理法是其中常用的几种。每一种方法都具有一些其他方法不具备的潜在性能优势。 10A second area where the U.S. and Europe differed is in the humble matter of phone numbers. 美国和欧洲另一个不同之处在于“电话号码”这件小事上。 Consequently, the usual rule of caller pays also applies to mobile pho

26、nes in Europe (except for international calls where costs are split). 这样，“主叫付费” 的常规也可以应用于欧洲的移动电话（费用分开的国际电话除外）。 Such systems, known as push-to-talk systems, were installed in several cities beginning in the late 1950s. 20世纪50年代末，有几个城市开始架设这样的系统（被称之为“按下通话系统”) Also, due to the large power of the hilltop

27、 transmitter, adjacent systems had to be several hundred kilometers apart to avoid interference. 此外，位于山顶上的发射机功率很大。为了避免互相干扰，临近系统间必须距离几百公里。 The key idea that gives cellular systems far more capacity than previous systems is the use of relatively small cells and the reuse of transmission frequencies in

28、 nearby (but not adjacent) cells. “采用较小蜂窝”和 “发射频率重用” 使蜂窝系统获得了比以往系统大得多的容量。 “发射频率重用” 是在附近小区中，而不是在相邻小区中。 Thus, the cellular design increases the system capacity by at least an order of magnitude, more as the cells get smaller. 这样，蜂窝设计将系统容量至少提高了一个数量级；而且蜂窝越小，提高量越大。 The MTSOs (Mobile Telephone Switching O

29、ffice) communicate with the base stations, each other, and the PSTN (Public Switched Telephone Network ) using a packet-switching network.移动电话交换局使用分组交换网络和基站、其他的移动电话交换局及公共服务电话网进行通信。On a D-AMPS mobile phone, the voice signal picked up by the microphone is digitized and compressed using a model that is

30、 more sophisticated than the delta modulation and predictive encoding schemes. 在D-AMPS 移动电话上，语音信号由麦克风拾取之后，先进行数字化，然后使用比增量调制和预测编码更复杂的模型进行压缩。 To a first approximation, GSM is similar to D-AMPS. Both are cellular systems. 乍一看，GSM 和D-AMPS很相似。两者都是蜂窝系统。With mobile telephony there is a huge gain from doing

31、digitization and compression in the handset, so much so that in D-AMPS, three users can share a single frequency pair using time division multiplexing. 对于移动电话而言，在电话机内完成数字化并进行数据压缩有很大好处这样一来，3个D-AMPS用户可以通过时分复用共用一对频率。 Theoretically, 992 channels can be supported in each cell, but many of them are not av

32、ailable, to avoid frequency conflicts with neighboring cells. 理论上讲，每个蜂窝小区可以支持992个信道；但为了避免和邻近蜂窝小区发生频率冲突，许多信道并不能使用。 Thus, the key to CDMA is to be able to extract the desired signal while rejecting everything else as random noise. 因此，CDMA的关键在于能够提取出希望得到的信号，而把其他信号当作随机噪声而加以抑制。 Each station is assigned a unique m-bit code called a chip sequence. To transmit a 1 bit, a station sends its chip sequence. To transmit a 0 bit, it sends the ones complement of its chip sequence. 每个（移动）站分配到唯一的一个称为“码片序列”的m位码