电信专业英英词典F-1_电脑电信

　fade - this is a reduction in the received signal. it is caused by absorption, refraction, or reflection.

　fax - this is a shortening of facsimile, and it refers to one fax machine sending a digital representation of a hardcopy over the phone lines to be received and printed out by another fax machine.

　fcc - see federal communications commission

　f/d - the ratio of antenna's focal length to the antenna's diameter. if there is a greater f/d it means there is a shallower dish.

　fdm - see frequency division multiplexing.

　feature - this term refers to any of the tasks that a particular piece of equipment can perform or carry out.

　feed - this (1) describes the physical feed system of the antenna, and (2) describes the actual signal transmission of the data or information from the distributors.

　feedback - this occurs when part of the output signal returns to the input side of the electronic device.

　federal communications commission (fcc) - this is the government agency that regulates all interstate communications that originate within the united states. the fcc has no intrastate authority.

　field - this refers to the particular location of a piece of data within a record (which is within a file of a database).

　file - this term refers to any intended collection of data with similar characteristics. a file could be anything from a document to a component of a computer program.

　filter - this is a device which allows a particular spectrum (range of frequencies) to pass through it but prohibits (attenuates) all others from passing.

　firewall - this is a system of both software and hardware, and it has purpose of limiting the vulnerability of a computer or set of computers from outside attack (i.e., hacking).

　flash - this is a function on a telephone or other phone device that rapidly hangs-up and reconnects the telephone line.

　flag - in programming, this is a variable that is used to relay when a particular condition of the program has been met.

　flow control - this is a method of controlling the transfer of information (messages, characters, etc.) between a network's data points.