ETR 250 : 20001

Foreword
Introduction
1 Scope
2 References
3 Definitions and abbreviations
   3.1 Definitions
   3.2 Abbreviations
4 Typical network components and configurations
   4.1 Network components
   4.2 Network configurations
5 General considerations; individual parameters and combination
   effects
6 Individual transmission parameters
   6.1 General survey of the individual transmission parameters
   6.2 Basic attenuation/frequency response parameters
   6.3 Overall, send, receive and circuit loudness ratings
   6.4 Sidetone
   6.5 Echo and stability
   6.6 Transmission time
   6.7 Noise and quantizing distortion
   6.8 Power handling and non-linear distortion
   6.9 Crosstalk
   6.10 Effects of time-varying impairments
7 Equipment and systems with special transmission properties
   7.1 Echo control devices
   7.2 Low bit-rate codecs
   7.3 Digital Circuit Multiplication Equipment (DCME)
   7.4 Mobile communication systems
   7.5 ATM systems
8 Combination effects of impairments on speech communication
   quality - background to the ETSI model
   8.1 Introduction
   8.2 Derivation of the ETSI model
   8.3 Estimates of users' reactions given in the ETSI model
   8.4 Discussion of ratings and impairment factors in the
        ETSI model
   8.5 Future up-dating and amendments of the ETSI model
9 A computation model for the overall voice transmission
   quality from mouth to ear
   9.1 Description of algorithms in the ETSI model
   9.2 Comparisons of results from the ETSI model, other
        models and subjective tests
   9.3 Future verification of the ETSI model
   9.4 Application of the ETSI model in transmission planning
   9.5 Statistical use of the ETSI-model for quality control
        of existing networks: some guidelines
10 Assessment of end-to-end voice transmission performance of
   networks
   10.1 General
   10.2 Assessment of customer opinion
   10.3 Objective parameter measurements
Annex A: Impedance strategy in 2-wire networks
Annex B: Noise aspects in understanding overall network
         performance
Annex C: Absolute and relative level
Annex D: Technical report on echo cancelling
Annex E: A discussion of subjective tests
Annex F: Some examples of voice transmission quality evaluations
         by the ETSI model
Annex G: Consideration of low bit-rate codecs in transmission
         planning
Annex H: Transmission Quality of Digital Circuit Multiplication
         Equipment (DCME)
Annex J: Usability of telecommunication services; price and
         quality considerations
Annex K: Some notes on the verification of the ETSI computation
         model
Annex L: Propagation delay and echo control procedures
Annex M: Aspects of voice transmission quality which need further
         studies
Annex N: Bibliography
History