重点词汇
1.TDM——Time Division Multiplexing 时分复用 FDM CDM
2.PCM——Pulse Code Modulation 脉冲编码调制
3.PCI——Peripheral Component Interconnect 周边元件连接口
4.IDE——Integrated Drive Electronics 集成驱动器电路
5.AGP——Accelerated Graphic Port 加速图形接口
6.USB——Universal Serial Bus通用串行接口
7.HDL——Hardware Description Language 硬件描述语言
8.PLD——Programmable Logic Device 可编程逻辑器件
9.FPGA——Field Programmable Gate Array 现场可编程门阵列
10.ASIC——Application—Specific Integrated Circuit专用集成电路
11.DSP——Digital Signal Processor 数字信号处理器
12.SoC——System-on-Chip 片上系统
13.Learnning curve 学习曲线
14.IEEE——Institute of Electrical and Electrics Engineers
电气与电子工程师学会
15.sample and hold circuit 采样与保持电路
16.price/performance ratio 性能价格比
17.harvard architecture 哈佛结构
18.looping scheme 循环机制
19.FFT——Fast Fourier transform 快速傅里叶变换
20.PCB——Printed Circuit Board 印刷电路板
21.SPS——Sample Per Second 每秒样本数
22.block diagram 方框图
23.Dolby Stereo 杜比立体声
24.transmission bandwidth 传输带宽
25.signal-to-noise ratio 信噪比
汉译英句子
1."信道"这个术语通常是指频分多址系统中的一个频率，时分多址系统中的一个时隙，码分多址系统中的一个代码或混合系统中的频率，时隙，代码中的某中组合。
The generic term channel is normally used to denote a frequency in FDMA system,a time slot in TDMA system,and a code in CDMA system or a combination of these in a mixed system.
2.第三代系统的目的在于为用户提供一个支持语音，数据，多媒体和视频服务的无隙网络，而不论用户在网络中的什么位置。
The third-generation systems aim to provide a seamless network that can provide users voice,data，multimedia,and video services regardless of their location on the network.
3.逻辑综合是将电子线路的高级描述转换为一张逻辑门极其互连列表(即“网表”)的过程。逻辑综合程序都能理解Verilog和VHDL的某个子集。
Logic synthesis is the conversion of a high-level electronic circuit description into a list of logic gates and their interconnections,called the "netlis". Every logic synthesis program understands some subset of Verilog and VHDL.
4."复杂可编程逻辑器件"是一种在逻辑模块之间具有可编程互连的可编程逻辑器件。多数复杂可编程逻辑器件是基于电可擦写可编程只读存储器和闪存的。
CPLD(Complex PLD)is a programmable logic device that includes a reprogrammable interconnect between the logic blocks.CPLDs are mostly EEPROM and flash based.
1
5.数字信号处理器(DSP)是无数家用和商用系统的关键部分，其应用领域与日俱增。因此，DSP正在成为技术专家和工程师专业知识的重要组成部分之一。
Digital signal processing is an essential element of countless home and business systems. Its domain can only increase as time proceeds.Thus,
DSP is becoming an essential area of expertise for technologists and engineers.
6.信号(如声音，光和电压)是携带信息的变化。模拟信号是现实世界中的信号。模拟信号在每个时间点上都有定义，其幅度的取值是无限的。
Signals ,like sound,light,or voltage,are information-bearing variations.
Analog signals are real-world signals.They are defined at every point in time and may take an infinite number of possible amplitudes.
英译汉句子
1.Using better compression algorithms, it is possible to get the speech down to 4kbps , in which case six users can be stuffed into a frame, as illustrated in Figure 11.(b).From the operator's perspective , being able to squeeze three to six times as many D-AMPS user is a huge win and explains much of the popularity of PCS.
如果使用更好的压缩算法，还可以把语音数据率降至4kbps；这样的话，一帧就可以容纳6位用户了。在运营商看来，“3—6位D—AMPS用户只需占用相当于1位AMPS用户所需的带宽”是巨大的成功，而且在很大程度上解释了“个人通信业务”（PCS,Personal Communication Service）普及的原因。
2.CDMA is completely different from AMPS ,D-AMPS, and GSM. Instead of dividing the allowed frequency range into a few hundred narrow channels, CDMA allows each station to transmit over the entire frequency spectrum all the time .Multiple simultaneous transmissions are separated using coding theory. CDMA also relaxes the assumption that colliding frames are totally garbled . Instead , it assumes that multiple signals add linearly.
CDMA和AMPS、D—AMPS及GSM完全不同。CDMA没有将可用频带分割为几百个窄带信道，而是允许信号在整个频谱范围内传送。利用编码原理，CDMA可以将多个同时传送的信号分离开来。在CDMA中，“相遇数据帧会造成数据混淆”的想法不存在了——CDMA认为多路信号之间是线性相加的。
3.Motherboard -This is the main circuit board that all of the other internal components connect to . The CPU and memory are usually on the motherboard . Other systems may be found directly on the motherboard or connected to it through a secondary connection . For example , a sound card can be built into the motherboard or connected through PCI .
主板：所有其他内部组件都和主板连接。通常，CPU和内部都位于主板上。其他组件可能直接位于主板上，也可能通过某种方式连接到主板上。例如，声卡可以置于主板上，也可以通过PCI总线连接到主板上。
4.In practical terms , this means that one or two layers of metal interconnect must be designed. Since an integrated circuit requires seven or more processing stages , all the processing steps other than the final metalization can be completed in advance . Because the uncommitted gate arrays can be produced in volume ,the cost of each device is relatively small.
从实现角度看，就是要设计一层或两层的金属互连线。集成电路的制造流程分为七个步骤（或更多），除去最后一步“金属化”(metallization)之外，其他步骤都可以提前完成。由于门阵列可以大量生产，所以单个器件成本就比较低。
5.Physical layer communications : FPGAs have long used to implement the glue logic that interfaces between physical layer communication chips and high-level networking protocol layers . The fact that today's high-end FPGAs can contain multiple high-speed transceivers means that communications and networking functions can be consolidated into a single device.
物理层通信：长久以来，FPGA用于实现通信芯片和高级网络协议之间的“胶连”逻辑。实际上，今 2
天的高端FPGA可以容纳多个高速无线收发器——即可将通信和网络功能固化于单个器件中。
6.One of the most important applications of VHDL is to capture the performance specification for a circuit , in the form of what is commonly referred to as a test bench . Test benches are VHDL descriptions of circuit stimuli and corresponding expected outputs that verify the behavior of a circuit over time . Test benches should be an integral part of any VHDL project and should be created in tandem with other descriptions of the circuit.
VHDL最重要的应用之一是以所谓“测试平台”（test bench）的形式记录电路的性能指标。“测试平台”是验证电路时域行为的激励源及相应期望输出的VHDL描述。在VHDL工程项目中，“测试平台”是必不可少的，应该和其他电路描述一同创建。
7.A digital signal is a numerical representation of the analog signal .It may be easier and cost effective to process these signals in the digital world .In the real world ,we can convert these signals into digital signals through the analog-to-digital converter ,process the signals,and if needed ,bring the signals back out to the analog world through the digital-to-analog converter.
数字信号是模拟信号的数值表示。在数字世界里，对这些信号进行处理可能会更容易、成本更低。在现实世界中我们可以通过“模数转换”将信号转换为数字信号，然后对信号进行处理；如果需要的话，用“数模转换器”将信号转换回到模拟世界中去。
8.Keep in mind that the distinction between DSPs and other microprocessors is not always a clear line .For instance ,look at how Intel describes the MMX technology addition to its Pentium processor : "Intel engineers have added 57 powerful new instructions specifically designed to manipulate and process video，audio and graphical data efficiently .These instructions are oriented to the highly parallel , repetitive sequences often found in multimedia operations . "
别忘了:DSPs和其他微处理器的界限并不是很清晰。例如，让我们看一看inte是如何描述其奔腾处理器新增的MMX技术的：“为了高效操作和处理视频、音频和图形数据，intel工程师新增了57条功能强大的指令。这些指令面向的是多媒体操作中经常出现的、高度并行和重复的程序。”
9.In practical application , these are certainly many other factors to consider when evaluating analog versus digital filters ,or analog versus digital signal processing in general . Most modern signal processing systems use a combination of analog and digital techniques in order to accomplish the desired function and take advantage of the best of both the analog and the digital world .
在实际应用中，在评价模拟滤波器和数字滤波器（或模拟信号处理和数字信号处理）的时候，坑定还要考虑许多其他因素。为了实现期望的功能和充分利用两种技术各自的优势，多数现代信号处理系统都采用了模拟技术和数字技术相结合的方式。
10.Audiophiles demand the utmost sound quality , and all that factors are treated as secondary .If you had to describe the mindest in the world , it would be : overkill . Rather than just matching the abilities of the human ear ,these systems are designed to exceed the limits of hearing . It's the only way to be sure that the reproduced music is pristine .Digital audio was brought to the world by the compact laser disc, or CD.This was a revolution in music ;the sound quality of the CD system far exceeds older systems, such as records and tapes
高保真音响爱好者对声音质量的要求极高，所有其他因素都被视为次要的。假如要用一个词来描述这种心理活动的话，那就是“过分”。高保真音响系统不是设计得刚好满足人类的听觉需求，而是超越了人类的听觉极限，这是唯一能够确保再现音乐无任何失真的办法。CD带给世人数字音频的享受。这是音乐领域里的巨大变化，CD系统的音质远远超过了传统的唱片磁带。
11.Then the sample are processed in groups of 1152 (about 26 msec worth). Each group is first passed through 32 digital filters to get 32 frequency bands . At the same time the input is fed into a psychoacoustic model in order to determine the masked frequencies .Next each of the 32 frequency bands is further transformed to provide a finer spectral resolution .
在这之后，样本以1152(约26ms)为一组进行处理。每组样本首先通过32个数字滤波器，从而得到32 3
个频带。同时，输入信号进入心理声学模型以决定被屏蔽的频率。下一步，32频带中的每个频带中的每个频率进一步变换得到更好的频谱分辨率。
4