PESQ
PESQ was accurately developed to be applicative to end-to-end voice-quality testing
under absolute arrangement conditions, like VoIP, Plain old blast annual (POTS), Integrated
services agenda arrangement (ISDN), and Global System for Mobile Advice (GSM).
PESQ was developed by KPN Research (now TNO Telecom), the Netherlands, and British
Telecommunications (BT), by accumulation the two avant-garde accent affection measures
PSQM+ and Perceptual Analysis Altitude System (PAMS).
PESQ, as approved in Figure 2-4, has acquired into ITU-T Recommendation P.862,
which is advised the accepted accepted for voice-quality measurement. PESQ can take
into annual codec errors, clarification errors, jitter problems, and adjournment problems that are
typical in a VoIP network. It combines the best of the PSQM adjustment forth with a
method alleged PAMS. PESQ array ambit from 1 (worst) through 4.5 (best), with 3.8 considered
toll affection (acceptable affection in a acceptable telephony network). PESQ is meant
to admeasurement alone one aspect of articulation quality. The furnishings of two-way communication,
such as loudness loss, delay, echo, and ancillary tone, are not reflected in PESQ scores.
62 Authorized Self-Study Guide: Cisco Articulation over IP (CVOICE)
Measurement
Model
Prediction of
Subjective Quality
Reference Signal
Degraded Signal
Network
Figure 2-4 PESQ Operation