在线英语听力室

电信专业英英词典M-3

时间:2006-08-18 16:00:00

(单词翻译:单击)

  Multimode Optical Fiber1(S)

  Multimode fibers2, with much wider cores than single mode fibers, allow light to enter at various angles, and reflect (bounce off of) core-clad boundaries as electromagnetic (light) wave propagates from transmitter to receiver. From a technical performance trade-off point of view, single mode fiber exhibits bandwidths of up to 100,000 MHz (MHz = 1,000,000 hertz or cycles per second = one megahertz) while multimode band width is in the range of 1,000 to 2,000 MHz (1,000 MHz = one billion hertz = one gigahertz = 1 GHz). See optical fiber(s); single modefiber(s).

  Multiplexing

  Multiplexing is a technique that enables a number of communications channels to be combined into a single broadband signal and transmitted over a single circuit. At the receiving terminal, demultiplexing of the broadband signal separates and recovers the original channels. Multiplexing makes more efficient use of transmission capacity to achieve a low per channel cost. Two basic multiplexing methods used in telecommunications systems, are frequency division multiplexing (FDM) and time division multiplexing (TDM).

  Major Trading Area (MTA) - An area defined by the U.S. government and used by the Federal Communications Commission (FCC) to designate personal communications services market areas.

  Mbps - Megabytes per second (MB is also used as an abbreviation for Megabyte).

  Megabyte (MB)- A million bytes or a thousand kilobytes.

  Miscellaneous Taxes - Like many other consumer goods and services, certain telephone services are taxed by federal, state, and local governments. These charges may appear as a ※gross receipts§ tax.

  Modem3 - A device for converting digital signals from your computer into analog4 signals for transmission over a phone line (modulation) and also converts the analog signals from the phone into digital signals that your computer can read (demodulation).


分享到:

Error Warning!

出错了

Error page: /mobile/?aid=24245&mid=3
Error infos: Got error 28 from storage engine
Error sql: select `l`.`tag`,`l`.`index`,`l`.`level_id`,`b`.`id`,`b`.`word`,`b`.`spell`,`b`.`explain`,`b`.`sentence`,`b`.`src` from `new_wordtaglist` `l` left join `new_word_base` `b` on `l`.`tag`=`b`.`word` where `l`.`arc_id`='24245' and `l`.`level_id`>='' group by `b`.`word` order by `l`.`index` asc