电信专业英英词典M-3_电脑电信

　multimode optical fiber(s)

　multimode fibers, 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.

　modem - a device for converting digital signals from your computer into analog 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).