ETSI ETR 250 TECHNICAL July 1996 REPORT Source: ETSI TC-TM Reference: DTR/TM-05006 ICS: 33.040.20 Key words: transmission, network, 3,1 kHz, speech, quality, planning, methodology Transmission and Multiplexing (TM); Speech communication quality from mouth to ear for 3,1 kHz handset telephony across networks ETSI European Telecommunications Standards Institute ETSI Secretariat Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [email protected] Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16 Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. © European Telecommunications Standards Institute 1996. All rights reserved. Page 2 ETR 250: July 1996 Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to "ETSI Editing and Committee Support Dept." at the address shown on the title page. Page 3 ETR 250: July 1996 Contents Foreword .....................................................................................................................................................11 Introduction..................................................................................................................................................11 1 Scope ................................................................................................................................................13 2 References........................................................................................................................................13 3 Definitions and abbreviations ............................................................................................................21 3.1 Definitions ..........................................................................................................................21 3.2 Abbreviations .....................................................................................................................22 4 Typical network components and configurations ..............................................................................24 4.1 Network components .........................................................................................................24 4.2 Network configurations ......................................................................................................24 5 General considerations; individual parameters and combination effects..........................................26 6 Individual transmission parameters...................................................................................................28 6.1 General survey of the individual transmission parameters ................................................28 6.1.1 Overview........................................................................................................28 6.1.2 The human speech and hearing parameters ................................................28 6.1.3 The voice transmission attenuation between talker and listener...................33 6.1.4 Talker and listener sidetone ..........................................................................33 6.1.5 Echo and stability ..........................................................................................33 6.1.6 Transmission time .........................................................................................34 6.1.7 Noise and quantizing distortion .....................................................................34 6.1.8 Power handling and non-linear distortion ......................................................34 6.1.9 Crosstalk .......................................................................................................34 6.2 Basic attenuation/frequency response parameters ...........................................................34 6.2.1 General..........................................................................................................34 6.2.2 Handset telephone characteristics ................................................................36 6.2.3 Subscriber line attenuation............................................................................40 6.2.4 4-wire circuits ................................................................................................41 6.3 Overall, send, receive and circuit loudness ratings ...........................................................43 6.3.1 General..........................................................................................................43 6.3.2 Overall Loudness Rating (OLR) ....................................................................44 6.3.3 Send and Receive Loudness Ratings (SLR and RLR)..................................44 6.3.4 Conversions to and from other loudness loss related values........................44 6.4 Sidetone.............................................................................................................................45 6.4.1 General..........................................................................................................45 6.4.2 Electric and acoustic paths of the sidetone, calculation of STMR and LSTR .............................................................................................................45 6.4.3 Relation between STMR and LSTR ..............................................................47 6.4.4 Recommendations for STMR........................................................................47 6.4.5 Recommendations for LSTR.........................................................................49 6.4.6 Sidetone distortion.........................................................................................49 6.4.7 A comparison between talker sidetone and talker echo................................50 6.5 Echo and stability...............................................................................................................50 6.5.1 General..........................................................................................................50 6.5.2 The principle of echo.....................................................................................50 6.5.2.1 Talker echo..........................................................................50 6.5.2.2 Listener echo .......................................................................51 6.5.2.3 Echo sources and echo loss................................................51 6.5.2.4 Multiple echoes....................................................................53 6.5.3 Stability ..........................................................................................................53 6.5.4 Definitions for echo and stability....................................................................54 Page 4 ETR 250: July 1996 6.5.5 Methods for the control of echo and stability ................................................ 56 6.5.5.1 Loss contribution................................................................. 56 6.5.5.2 Echo control devices........................................................... 57 6.5.6 Acceptable limits and planning rules ............................................................ 57 6.5.6.1 Limits for stability................................................................. 57 6.5.6.2 Limits for echo..................................................................... 58 6.6 Transmission time............................................................................................................. 62 6.6.1 Limits for transmission time.......................................................................... 62 6.7 Noise and quantizing distortion ......................................................................................... 63 6.7.1 General ......................................................................................................... 63 6.7.2 Circuit noise, quantizing noise and distortion................................................ 64 6.7.3 Addition of noise sources in a connection; equivalent noise in a 0 dBr point .............................................................................................................. 65 6.7.4 Ambient (room) noise ................................................................................... 65 6.7.5 Induced noise on subscriber lines ................................................................ 66 6.7.6 The subjective effects of non-stationary noise ............................................. 66 6.8 Power handling and non-linear distortion .......................................................................... 67 6.8.1 Amplitude characteristics of the speech signal............................................. 67 6.8.2 Power handling, FDM systems ..................................................................... 68 6.8.3 Power handling, PCM systems..................................................................... 69 6.8.4 Measurements of actual signal levels in networks ....................................... 69 6.8.5 Effects of non-linear distortion ...................................................................... 70 6.9 Crosstalk ..........................................................................................................................