Glossary Of Terms - OPTICOM OPERA - V 3.5 User Manual

Glossary of Terms

ACR
Absolute category rating test method according to the ITU-T recommendation P.800 used for the
assessment of speech codecs. Within the ACR test method, a five grade impairment scale is applied.
Because of the telecomunication environment the testing is done without a comparison to an undistorted
reference.
ADB
Average Distorted Block
ADPCM
According to standard ITU-T G.726. Bit rate of 32 kbit/s (also possible with 16, 24 and 40
kbit/s).
AES
The Absolute Error Score (AES) is derived from a formula developed especially for evaluating the quality
of the results obtained from an objective perceptual measurement method. It takes the confidence
intervals of the average values of subjective listening tests into account
Artefact
Spurious effects or imperfections introduced into a signal as a result of signal processing.
ATM
Asynchronous Transfer Mode
ASD
Auditory Spectral Difference, a psychoacoustically motivated measure for the audible difference between
two sounds.
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