Page 306 - Electrical Engineering Dictionary

full width at half max (FWHM) the function test a check for correct device
width of a distribution function (i.e., the hor- operation generally by truth table verifica-
izontal distance between two points having tion.
the same vertical coordinate) defined at a
vertical position halfway between the max- function-orienteddesign adesignmethod-
imum and minimum. This value exists for ology based on a functional viewpoint of a
certain functions that are of interest as pos- system starting with a high-level view and
sible point spread functions (e.g., Gaussian, progressively refining it into a more detailed
Moffat function) and gives a rough idea of design.
the amount of blur to be expected.
functional block ASICs designed using
fully associative cache a cache block this methodology are more compact than ei-
mapping technique where a main memory ther gate arrays or standard cells because
block can reside in any cache block position. the blocks can perform much more complex
A number of bits from the address received functions than do simple logic gates.
from the CPU is compared in parallel with
the cache tags to see if the block is present functional decomposition the division of
in the cache. Although costly to implement, processes into modules.
and impractical for large cache sizes, it is
the most flexible mapping method. See also functional redundancy checking an er-
cache, direct mapped cache, and associativ- ror detection technique based on checking
ity. bus activity generated by a processor (mas-
ter) with the use of another slave processor
function a programming construct that which monitors this activity.
creates its own frame on a stack, accepting ar-
guments, performing some computation, and functionalunit amodule, typicallywithin
returning a result. a processor, that performs a specific limited
set of functions. The adder is a functional
function sensitivity in a circuit described unit.
by the function F(s, x) where s is a complex
variable, and x is a passive or active element fundamental component the first order
in the circuit realization of the function, the component of a Fourier series of a periodic
equation waveform.

S F(s,x) = ∂F(s, x) x fundamental frequency for a continuous
x
∂x F(s, x)
time periodic signal, f(t) with fundamental
Under conditions of sinusoidal steady state, period T (seconds), ω 0 = 2π/T (rad/sec).
when s = jω, the function F(jω, x) is de- See also periodic signal.
scribed by the sensitivity
fundamental mode (1) operating mode of
S F(jω,x) = Re S F(jω,x) + j Im S F(jω,x) a circuit that allows only one input to change
x
x
x
at a time.
∂argF(jω, x)
= S |F(jω,x)| + j
x (2) lowest order mode of a laser cavity;
∂x/x
usually refers to a Gaussian transverse field
Thus, the real part of the function sensitivity distribution without regard to the longitudi-
gives the relative change in the magnitude nal mode order.
response, and the imaginary part gives the
change in the phase response, both with re- fuse an overcurrent device that employs
spect to a normalized element change. one or more fusible elements in series. The

c
2000 by CRC Press LLC