Page 266 - Electrical Engineering Dictionary
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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-



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