1 Purpose
2
Effect of individual impairments
2.1 General
2.2 Loudness loss
2.3 Circuit noise
2.4 Sidetone
2.5 Room noise
2.6 Attenuation distortion
2.7 Group-delay distortion
2.8 Absolute delay
2.9 Talker echo
2.10 Listener echo
2.11 Nonlinear distortion
2.12 Quantizing distortion
2.13 Phase jitter
2.14 Intelligible crosstalk
3
Effect of multiple impairments and the use of opinion models
Annex A – Transmission quality index
A.1 Introduction
A.2 Connection parameters used in the model
A.3 Basic model for transmission quality index
A.4 Typical results
Annex B – Effects of attenuation distortion on transmission performance
B.1 Effect of attenuation distortion on loudness and articulation
B.2 Effect of attenuation distortion on listening and conversation
opinion scores
B.3 Examples of attenuation distortion characteristics effect
B.4 Evaluation method using the attenuation distortion unit (adu)
Annex C – Effects of group-delay distortion on transmission performance
Annex D – Effects of carbon and linear microphones on transmission performance
Annex E – Quantizing distortion of digital systems
Annex F – Effects of nonlinear distortion on transmission performance
References