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Technical
Glossary - F
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Char., Number |
f
(See "femto" and "frequency")
Failure
The inability of a component or device to perform
its intended function as specified by the manufacturer.
Failure
Analysis
A rigorous investigation of the fundamental causes
of a failure.
Failure
Criteria
A specific description of a condition or characteristic
of a device that precludes the device from performing
its intended function as specified by the manufacturer
Failure
Mechanism
(See "Failure Mode")
Failure
Mode
The manner in which a failure occurs
Failure
Rate
The mean proportion of failures per unit time,
normally expressed in per cent per thousand hours
of operation.
Farad
The unit of capacitance, abbreviated as "F",
equal to 1 coulomb per volt.
FDDI
Fiber Distributed Digital Interface
Feedback
A portion of the output signal of a device or
system which is applied to the input of the system.
Feedback
Loop
The portion of a circuit whose purpose is to sample
the output of a system or component, process the
sample and apply the processed sample to the input
of the system or component. Feedback loops are
employed to either provide control or correction
to a circuit, or in the case of an oscillator,
to permit oscillation to occur.
Feedback
Path
(See "feedback loop")
femto
A prefix that stands indicates a factor of 10-15,
abbreviated as "f".
FET
(See "field effect transistor")
Fiber
Optics
Of or pertaining to the transmission of light
transparent fiber or fibers.
Field
Effect Transistor
A three or more terminal transistor that consists
of a channel and gate(s). At one end of the channel
there is an electrode called the source, into
which majority carriers flow from an external
circuit. At the other end of the channel there
is an electrode, called the drain, out of which
electrons flow into the external circuit. Application
of a voltage between the third terminal, known
as the gate, and the source, establishes an electric
field in the channel that changes the resistance
between the source and drain, thereby changing
the current that flows through the channel. In
some FET's, there is another gate terminal which
is independent of the first gate terminal.
Filter
A circuit that is designed to propagate signals
of a desired frequency or frequency interval and
to reject all other signals.
Fine
Leak Test
A test performed on packaged semiconductors to
determine the hermeticity of the package. Devices
are immersed, under high pressure, in gaseous
helium (He). They are placed in a vacuum chamber
designed to detect the presence and amount of
He. Packaged devices that have leak rates on the
order of 10-8 cc/atm/sec or less are considered
to be hermetic.
Flatness
The variation in attenuation or gain at a given
bias level over the frequency band of interest.
FM
(See "Frequency Modulation")
Forward
Bias
Bias voltage applied to a semiconductor PN junction
in the direction that causes electrons to flow
from the n-type (cathode) to the p-type (anode)
regions.
FQPSK
Filtered quadrature phase shift key modulation.
Frequency
The number of recurrences of a periodic phenomenon
per unit time. In electronics, we refer to the
frequency of electromagnetic radiation (radio
waves) and alternating electrical current, which
are periodic phenomena. The unit of frequency
is the Hertz, abbreviated as "Hz." Formerly,
the unit of frequency was known as cycles per
second, abbreviated as "cps."
Frequency
Band
Frequency range over which the performance or
characteristics of a circuit, device or component
are described or specified.
Frequency
Conversion
The translation of a signal from one frequency
to another.
Frequency
Converter (or simply, Converter)
A device or circuit that performs frequency conversion,
such as a mixer.
Frequency
Modulation
the modification of the frequency of a higher
frequency, constant magnitude carrier signal controlled
by the amplitude and phase of a lower frequency
baseband or audio signal.
Frequency
Multiplication
The increase in frequency of a signal by an integral
factor.
Frequency
Response
The amplitude of the transfer response of a circuit
or device plotted against the frequency interval
over which the response occurs.
FSK
Frequency shift key modulation.
Fundamental
Frequency
The primary, lowest frequency component of a wave.
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