Page 266 - Electrical Engineering Dictionary
P. 266
cuits exhibit a peak for each element pair and actions to them. Exception conditions/re-
a loss equal to L amax (maximum attenuation sponses table is a special type of event table.
loss across the band) at DC (low pass) or at
ω 0 (band pass). exact absolute controllability a dy-
namical system where the attainable set
even signal a signal that has even sym- K ∞ is equal to the whole state space
n
metry. If x(t) is an even signal, it satisfies W (2) ([−h, 0],R ).
1
the condition x(t) = x(−t). See also odd
signal. exact coding coding methods that repro-
duce the picture at the receiver without any
even-mode characteristic impedance loss. This method is also called information-
characteristic impedance of a circuit due to lossless or exact coding techniques. Four
an even-mode current or voltage excitation. methods of exact coding are run-length cod-
Often applied in the context of a transmis- ing, predictive coding, line-to-line predictive
sion line coupler where the even-mode ex- differential coding, block coding. However,
citation consists of applying equal amplitude several coding schemes use these in a hybrid
voltages or currents of identical phase on two manner.
conductors. The resulting impedance under
this excitation is defined as the even mode exact controllability of infinite dimen-
characteristic impedance. sional system an infinite dimensional sys-
tem where the attainable set K ∞ is equal to
even-order response circuit gain or inser- the whole state space X.
tion loss versus frequency response in which
there are an even number of peaks in the rip- exception (1) an unusual condition aris-
ple pattern, due to an even number of paired ing during program execution that causes the
elements in the circuit. Even-order circuits processor to signal an exception. This signal
exhibit a peak for each element pair and a activates a special exception handler that is
loss equal to L amax (maximum attenuation designed to handle only this special condi-
loss across the band) at DC (low pass) or at tion. Division by zero is one exception con-
ω o (band pass). dition. Some vendors use the term “trap” to
denote the same thing.
event (1) a nonsequential change in the (2) an event that causes suspension of nor-
sequencing of macroinstructions in a com- mal program execution. Types include ad-
puter. Events can be caused by a variety of dressing exception, data exception, operation
factors such as external or internal interrupts exception, overflowexception, protectionex-
(traps) or branch statements. ception, underflow exception.
(2) a specific instance taken from some
sample space, normally with an associated exception handler a special block of sys-
probability or probability density; also com- tem software code that reacts when a spe-
monly an idealized infinitesimal point in cific type of exception occurs. If the excep-
(x,y,z,t) space at which some occurrence is tion is for an error that the program can re-
taken to happen. For example, a flash of light cover from, the program can recover from the
at time t 0 at position (x 0 ,y 0 ,z 0 ) — event error and resume executing after the excep-
(x 0 ,y 0 ,z 0 ,t 0 ) — will lead at a later time t 1 tion handler has executed. If the programmer
to a wave of light passing a point (x 1 ,y 1 ,z 1 ) does not provide a handler for a given excep-
— namely event (x 1 ,y 1 ,z 1 ,t 1 ). tion, a built-in system exception handler will
usually be called, which will result in termi-
event table table listing all events, and nating the process that caused the exception.
their corresponding effects as well as re- Finally, the reaction to exception can be halt-
c
2000 by CRC Press LLC