Page 264 - Electrical Engineering Dictionary

1)/2], where [x] denotes the largest integer error recovery process of regaining oper-
contained in x. ational status and restoring system integrity
after the occurrence of an error with the use
error detecting code code used when of special hardware and software facilities.
communication data information in and be-
tween computer systems to ensure correct error state diagram a diagram that il-
data transfer. An error detecting code has lustrates all possible error events with re-
enough redundancy (i.e., extra information spect to an assumed reference event, e.g., an
bits) in it to allow for the detection of the error sequence compared to a reference se-
original data, after some of its bits have been quence, both produced by a finite state ma-
the subject of error in the transmission. The chine. All possible sequences that diverge
number of erroneous bits that can be detected and later merge with the reference sequence
by the receiver using this code depends on the are accounted for in the diagram. The trans-
Hamming distance between the transmitted fer function of the error state diagram can
codewords. See also error-correcting code. be used for performance evaluation of detec-
tion/decoding algorithms working on noise
outputs from a finite state machine.
error detection the process of detecting
if one or more errors have occurred during a
error-correction the mechanism by
transmission of information. Channel codes
which a receiving circuit is able to cor-
are suitable for this purpose. The family of
rect errors that have occurred in an encoded
CRC-codes are an example of channel codes
transmission. See also Hamming code,
specially designed for error detection. See
error-correcting code.
also error detecting code.
ESD See electrostatic discharge.
error detection capability the capability
of a code to detect error is bounded by the
ESDI See enhanced small disk interface.
minimum distance, and for an (n, k) block
code, it is given by d min − 1.
ESI See equivalent sphere illumination.
error extension the multiplication of er- ESPRIT acronym for estimation of sig-
rors that might occur during the decoding of a
nal parameters via rotational invariance tech-
line coded sequence, or during the decoding
niques. A subspace-based estimation tech-
of a forward error control coded sequence
nique based on two identical, displaced sen-
when the number of symbol errors exceeds
sor arrays.
the error correction capability of the code.
estimation in adaptive control, a key role
error function mathematical function is played by on-line determination of process
over some interval in which a calculated re- parameters. A recursive parameter estimator
sult is compared to a known quantity (usually is present in many adaptive control schema
data) by utilizing a difference quantity to de- such as self-tuning regulator (explicitly) or
termine how well the mathematical function model-reference adaptive controller (implic-
replicates the known quantity over that inter- itly).
val. Most error functions utilize an area or Usually, parameters estimation is viewed
least squares difference function. in the broader context of system identifi-
cation formed by selection of model struc-
error latency length of time between the ture, experiment design, parameters estima-
occurrence of an error and the appearance of tion, and validation. In adaptive control, the
the resulting failure. parameters vary continuously, and it is nec-

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