电信专业英英词典F-4

　　Frame

　　In time division multiplexing systems, Frame is a sequence of time slots each containing a sample from one of the channels carried by the system. The frame is repeated at regular intervals¹, (normally the sampling rate used in analog²-to-digital conversion³ processes for signals being multiplexed) and each channel usually occupies the same sequence position in successive frames.

　　Frame Relay

　　Frame relay is a network interface⁴ protocol⁵ defined in CCITT Recommendation 1.122 "Framework for additional packet mode bearer services," as a packet mode service. In effect it combines the statistical⁶ multiplexing and port sharing of X.25 packet switching with the high speed and low delay of time division multiplexing and circuit switching. Unlike X.25, frame relay implements⁷ no layer 3 protocols⁸ and only the so-called core layer 2 functions. It is a high-speed switching technology that achieves ten times the packet throughput of existing X.25 networks by eliminating two-thirds of the X.25 protocol complexity⁹ The basic units of information transferred are variable length frames, using only two bytes for header information. Delay for frame relay is lower than for X.25, but it is variable and larger than that experienced in circuit switched networks. This means that currently frame relay is not suitable for voice and video applications where excessive and variable delays are unacceptable.

　　Frequency

　　Frequency is acoustic¹⁰ waves and electrical signals might be made up of only a single tone, like a single note on a piano. In this case the signal waveform is made up of repeating identical "cycles" and is said to be of a single frequency, equal to the number of cycles that occur in one second of time. In communications, frequency was traditionally expressed in cycles per second, but is now expressed in hertz (Hz), still equal to one cycle per second. Thus, one thousand cycles per second is equal to one thousand hertz, or a kilohertz (kHz).

　　Frequency Division Multiplexing (FDM)

　　FDM divides the frequency bandwidth (spectrum) of a broadband transmission circuit into many subbands, each capable of supporting a single, full time communications channel on a non- interfering¹¹ basis with other multiplexed channels. FDM multiplexing is generally suitable for use with analog carrier transmission systems.

　　FSS

　　fully¹² separated subsidiary

　　FTAM

　　file transfer access & management

　　Full Duplex

　　Full duplex is a transmission path capable of transmitting signals in both directions simultaneously¹³.

　　FX

　　foreign exchange

1 intervals   

n.[军事]间隔( interval的名词复数 )；间隔时间；[数学]区间；（戏剧、电影或音乐会的）幕间休息

参考例句：

• The forecast said there would be sunny intervals and showers. 预报间晴，有阵雨。
• Meetings take place at fortnightly intervals. 每两周开一次会。

2 analog   

n.类似物，模拟

参考例句：

• The analog signal contains high-frequency video information,which helps make up the picture.模拟信号包括有助于构成图像的高频视频信息。
• The analog computer measures continuously,without proceeding step by step.模拟计算机不是一步一步地进行，而是连续地进行量度。

3 conversion   

n.转化，转换，转变

参考例句：

• He underwent quite a conversion.他彻底变了。
• Waste conversion is a part of the production process.废物处理是生产过程的一个组成部分。

4 interface   

n.接合部位，分界面；v.(使)互相联系

参考例句：

• My computer has a network interface,which allows me to get to other computers.我的计算机有网络接口可以与其它计算机连在一起。
• This program has perspicuous interface and extensive application. 该程序界面明了，适用范围广。

5 protocol   

n.议定书，草约，会谈记录，外交礼节

参考例句：

• We must observe the correct protocol.我们必须遵守应有的礼仪。
• The statesmen signed a protocol.那些政治家签了议定书。

6 statistical   

adj.统计的，统计学的

参考例句：

• He showed the price fluctuations in a statistical table.他用统计表显示价格的波动。
• They're making detailed statistical analysis.他们正在做具体的统计分析。

7 implements   

n.工具( implement的名词复数 )；家具；手段；[法律]履行（契约等）v.实现( implement的第三人称单数 )；执行；贯彻；使生效

参考例句：

• Primitive man hunted wild animals with crude stone implements. 原始社会的人用粗糙的石器猎取野兽。 来自《现代汉英综合大词典》
• They ordered quantities of farm implements. 他们订购了大量农具。 来自《现代汉英综合大词典》

8 protocols   

n.礼仪( protocol的名词复数 )；（外交条约的）草案；（数据传递的）协议；科学实验报告（或计划）

参考例句：

• There are also protocols on the testing of nuclear weapons. 也有关于核武器试验的协议。 来自辞典例句
• Hardware components and software design of network transport protocols are separately introduced. 介绍系统硬件组成及网络传输协议的软件设计。 来自互联网

9 complexity   

n.复杂(性)，复杂的事物

参考例句：

• Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
• The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。

10 acoustic   

adj.听觉的，声音的；(乐器)原声的

参考例句：

• The hall has a fine acoustic.这个大厅的传音效果很好。
• Animals use a whole rang of acoustic, visual,and chemical signals in their systems of communication.动物利用各种各样的听觉、视觉和化学信号来进行交流。

11 interfering   

adj. 妨碍的 动词interfere的现在分词

参考例句：

• He's an interfering old busybody! 他老爱管闲事！
• I wish my mother would stop interfering and let me make my own decisions. 我希望我母亲不再干预，让我自己拿主意。

12 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

13 simultaneously   

adv.同时发生地，同时进行地

参考例句：

• The radar beam can track a number of targets almost simultaneously.雷达波几乎可以同时追着多个目标。
• The Windows allow a computer user to execute multiple programs simultaneously.Windows允许计算机用户同时运行多个程序。