Page 294 - Electrical Engineering Dictionary

(3) the foreground of a window is a single forward error correction (FEC) an er-
color or a pattern. The foreground text or ror control system used for simplex chan-
graphics is displayed against the background nels (only a forward channel) where the
of the window. channel code is used to determine the most
likely transmitted sequence of information
fork (1) the action of a process creating symbols. Compare with automatic repeat
another (child) process without ending itself. request.
(2) in Unix, fork is a process that can cre-
ate a new copy of itself (a child) that has its forward error recovery a technique (also
own existence until either it terminates (or is called roll-forward) of continuing processing
killed) or its parent terminates. The prepare by skipping faulty states (applicable to some
handler is called before the processing of the real-timesystemsinwhichoccasionalmissed
fork subroutine commences. The parent han- or wrong responses are tolerable).
dler is called after the processing of the fork
subroutine completes in the parent process. forwardvoltage thevoltageacrossthede-
The child handler is called after the process- vice when the anode is positive with respect
ing of the fork subroutine completes in the to the cathode.
child process.
forward wave in a traveling wave tube,
form term used to indicate the structure microwaves propagate in the same direction
and dimensions of a multiterm equation with- with electrons in the electron beam. Electro-
out details within component terms.
magnetic waves travel in the positive direc-
tion of the coordinate system.
formants the main frequencies that result
from typical short-time spectral analysis of
forward–backward procedure an effi-
vowels. Depending on the application, two
cient algorithm for computing the probabil-
or three formants are commonly extracted.
ity of an observation sequence from a hidden
Markov model.
forming gas a mixture of hydrogen and
nitrogen (typically 5% hydrogen and 95% ni-
forwarding (1) sending a just-computed
trogen), typically used in the post-metal an-
value to potential consumers directly, with-
nealing process in wafer fabrication.
out requiring a write followed by a read.
forward channel also referred to as for- (2) to immediately provide the result of
ward link, it is the radio link (channel) in a thepreviousinstructiontothecurrentinstruc-
cellular or microcellular network where the tion, at the same time that the result is written
base station is the transmitter and the mobile to the register file. Also called bypass.
terminal is the receiver. In the case of cel-
lular networks, the term is synonymous with Foster’s reactance theorem states that
down-link. The mobile to base station link is the driving-point impedance of a network
known as the reverse link or up-link. composed of purely capacitive and inductive
reactances is an odd rational function of fre-
forward converter an isolated version of quency.
a buck converter. The primary and the sec-
ondaryofthetransformerconductatthesame Foster–Seeley discriminator similar to
time. The transformer does not store energy. the balanced slope detector. A circuit used
An additional winding with a diode is often to convert an incoming FM signal to a re-
used to reset the magnetizing energy when lated AM signal to provide a demodulation
the transistor is off. process.

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2000 by CRC Press LLC