1、 - DIN1 DIN ETS 300583-6 96 2794442 O577306 899 W DEUTSCHE NORM Juli 1996 Europisches zellulares digitales Funkkommunikationssystem Teil 6: Sprachaktivitts-Detektor (VAD) fr Sprechkanle Half rate-Sprac hcodierung Englische Fassung ETS 300581-6 : 1995 DIN - ETS 300581-6 ICs 33.060.50 Deskriptoren: Te
2、lekommunikation, Kommunikationssystem, Sprachcodierung, Halfrate-Sprachcodierung, Sprechkanal European digital cellular telecommunications system - Half rate speech - Part 6: Voice Activity Detector (VAD) for half rate speech traffic channels; English version ETS 300581-6 : 1995 Die Europische Telek
3、ommunikationsnorm ETS 300581-6 : 1995 hat den Status einer Deutschen Norm. Nationales Vorwort Die vorliegende Norm ist auf der Grundlage der vom Europischen Institut fr Telekommunika- tionsnormen (ETSI) herausgegebenen Europischen Telekommunikationsnorm ETS 300581 -6, Ausgabe November 1995, “Europea
4、n digital cellular telecommunications system - Half rate speech - Part 6: Voice Activity Detector (VAD) for half rate speech traffic channels“, verffentlicht worden. Diese Norm enthlt unter Bercksichtigung des DIN- Prsidialbeschlusses 13/1983 den englischen Originaltext der vom Technischen Komitee S
5、MG des ETSI erarbeiteten ETS 300581 -6. Fachlich zustndig in Deutschland ist das Komitee K 736 “Bewegliche Funkdienste“ der Deutschen Elektrotechnischen Kommission im DIN und VDE (DKE). Fortsetzung 23 Seiten ETS-Original Deutsche Elektrotechnische Kommission im DIN und VDE (DKE) DIN Deutsches Instit
6、ut fr Normung e.V. . Jede Art der Vervielfliigung. auch auszugsweise, Ref. Nr. DIN ETS 300581-6 : 1996-07 Preisgr. 09 Verrr.-Nr. 1709 nur mit Genehmigung des DIN Deutsches Institut fur Normung e.V., Berlin, gestattet. Alleinverkauf der Normen durch Beuth Verlag GmbH, 10772 Berlin DIN1 DIN ETS 300581
7、-6 96 2794442 0577207 725 W ETS 300 581-6 Novem ber 1995 Source: ETSI TC-GSM Reference: DE/SMG-020642 ICs: 33.060.50 Key words: European digital cellular telecommunications system, Global System for Mobile communications (GSM) European digital cellular telecommunications system; Half rate speech Par
8、t 6: Voice Activity Detector (VAD) for half rate speech traffic channels (GSM 06.42) ETSI European Telecommunications Standards Institute ETSI Secretariat Postal address: F-O6921 Sophia Antipolis CEDW - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE X.400: c=fr,
9、 a=atlas, p=etsi, c=secretariat - Internet: secretariatetsi.fr Tel.: +33 92 94 42 O0 - 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. O European Teleco
10、mmunications Standards Institute 1995. All rights reserved. DIN1 DIN ETS 300581-6 76 2774442 0577308 bb3 = Page 2 ETS 300 581-6: November 1995 (06.42 version 4.1.1) Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or othetwise, ma
11、y 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. DIN1 DIN ETS 3005L-6 96 2794442 0577109 5TB Page 3 ETS 300 581-6: November 1995 (06.42 version 4.1.1) Contents Foreword . 5 1 Scope 7 2 Normative
12、references 7 3 Definitions. symbols and abbreviations . 3.1 3.2 Definitions . 7 3.3 4 General 1 0 5 Functional description 10 5.1 Overview and principles of operation 10 5.2 Algorithm description . 10 5.2.1 5.2.2 ACF averaging 12 5.2.3 Predictor values computation 12 5.2.4 Spectral comparison 13 5.2
13、.5 Information tone detection . 13 5.2.6 Threshold adaptation . 14 5.2.7 VAD decision . 17 5.2.8 VAD hangover addition 17 5.2.9 Periodicity detection 17 Adaptive filtering and energy computation . 11 6 Computational description overview . 18 6.1 VAD modules . 6.2 Pseudo-floating point arith 19 Annex
14、 A (informative): VAD performance . 20 Annex E! (informative): Simplified block filtering operation 21 Annex C (informative): Pole frequency calculation 22 History . 23 DIN1 DIN ETS 300583-6 96 2794442 057711D 21T Page 4 ETS 300 581-6: November 1995 (06.42 version 4.1.1) Blank page DIN1 DIN ETS 3005
15、81-6 96 2794442 0577LL1 156 Page 5 ETS 300 581-6: November 1995 (06.42 version 4.1.1) Foreword This European Telecommunication Standard (ETS) has been produced by the Special Mobile Group (SMG) Technical Committee of the European Telecommunications Standards Institute (ETSI). This ETS specifies the
16、half rate speech traffic channels for the European digital cellular telecommunications system. This ETS corresponds to GSM technical specification, GSM 06.42, version 4.1.1 and is part 6 of a multi-part ETS covering the half rate speech traffic channels as described below: GSM 06.02 GSM 06.20 GSM 06
17、.21 GSM 06.22 GSM 06.41 GSM 06.42 GSM 06.06 GSM 06.07 NOTE: ETS 300 581-1 : “European digital cellular telecommunications system; Half rate speech Part 1: Half rate speech processing functions“. ETS 300 581 -2: “European digital cellular telecommunications system; Half rate speech Part 2: Half rate
18、speech transcoding“. ETS 300 581-3: “European digital cellular telecommunications system; Half rate speech Part 3: Substitution and muting of lost frames for half rate speech traffic channels“. ETS 300 581-4: “European digital cellular telecommunications system; Half rate speech Part 4: Comfort nois
19、e aspects for half rate speech traffic channels“. ETS 300 581-5: “European digital cellular telecommunications system; Half rate speech Part 5: Discontinuous Transmission (DTX) for half rate speech traffic channels“. ETS 300 581 -6: “European digital cellular telecommunications system (Phase 2); Hal
20、f rate speech Part 6: Voice Activity Detection (VAD) for half rate speech traffic channels“. ETS 300 581 -7: “European digital cellular telecommunications system; Half rate speech Part 7: ANSI-C code for the GSM half rate speech codec“. ETS 300 581 -8: “European digital cellular telecommunications s
21、ystem; Half rate speech Part 8: Test vectors for the GSM half rate speech codec“. TC-SMG has produced documents which give the technical specifications for the implementation of the European digital cellular telecommunications system. Historically, these documents have been identified as GSM Technic
22、al Specifications (GSM-TS). These TSs may have subsequently become Interim European Telecommunication Standards (I-ETSs), (Phase l), or European Telecommunication Standards (ETSs), (Phase 2), whilst others may become ETSI Technical Reports (ETRs). Transposition dates Date of adoption of this ETS: 27
23、 October 1995 Date of latest announcement of this ETS (doa): 28 February 1996 Date of latest publication of new National Standard or endorsement of this ETS (dop/e): 31 August 1996 I Date of withdrawal of any conflicting National Standard (dow): 31 August 1996 DIN1 DIN ETS 300581-6 96 2794442 057711
24、2 O92 Page 6 ETS 300 581-6: November 1995 (06.42 version 4.1.1) Blank page DIN2 DIN ETS 300583-6 96 D 2774442 0577223 T27 D Page 7 ETS 300 581-6: November 1995 (06.42 version 4.1.1) i Scope This European Telecommunication Standard (ETS) specifies the Voice Activity Detector WAD) to be used in the Di
25、scontinuous Transmission (DTX) as described in GSM 06.41 (ETS 300 581-5) 4. It also specifies the test methods to be used to verify that a VAD implementation complies with this ETS. The requirements are mandatory on any VAD to be used either in GSM Mobile Stations (MS)s or Base Station Systems (BSS)
26、s that utilise the half-rate GSM speech traffic channel. 2 Normative references This ETS incorporates by dated and undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated re
27、ferences, subsequent amendments to or revisions of any of these publications apply to this ETS only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. 31 41 GSM O1 .O4 (ETR 100): “European digital cellular telecommunic
28、ations system; Abbreviations and acronyms“. GSM 06.20 (ETS 300 581-2): “European digital cellular telecommunications system; Half rate speech Part 2: Half rate speech transcoding“. GSM 06.22 (ETS 300 581-4): “European digital cellular telecommunications system; Half rate speech Part 4: Comfort noise
29、 aspects for half rate speech traffic channels“. GSM 06.41 (ETS 300 581-5): “European digital cellular telecommunications system; Half rate speech Part 5: Discontinuous transmission (DTX) for half rate speech traffic channels“. GSM 06.06 (ETS 300 581 -7): “European digital cellular telecommunication
30、s system; Half rate speech Part 7: ANSI C code for the GSM half rate speech codec“. GSM 06.07 (ETS 300 581-8): “European digital cellular telecornmunications system; Half rate speech Pari 8: Test sequences for the GSM half rate speech codec“. 3 Definitions, symbols and abbreviations 3.1 Definitions
31、For the purpose of this ETS, the following definitions apply. noise: The signal component resulting from acoustic environmental noise. mobile environment: Any environment in which mobile stations may be used. 3.2 Symbols For the purpose of this ETS, the following symbols apply. 3.2.1 Variables aavl
32、acf adaptcount avo avl filter predictor values, see subclause 5.2.3 the ACF vector which is calculated in the speech encoder secondary hangover counter, see subclause 5.2.6 averaged ACF vector, see subclause 5.2.2 a previous value of avo, see subclause 5.2.2 (GSM 06.20 (ETS 300 581-2) 2) DIN1 DIN ET
33、S 300581-6 96 2794442 0577114 b5 Page 8 ETS 300 581-6: November lSSS(06.42 version 4.1.1) burstcount den difference dm hangcount lagcount lastdm lags num oldlagcount prederr ptch pvad ravl rc rvad smallag stat thvad tone vadflag veryoldlagcount vvad 3.2.2 Constants adP burstconst dec fac frames freq
34、th hangconst inc Ithresh margin nthresh plev predth Pth thresh speech burst length counter, see subclause 5.2.7 denominator of left hand side of equation 8 in annex C, see subclause 5.2.5 difference between consecutive values of dm, see subclause 5.2.4 spectral distortion measure, see subclause 5.2.
35、4 primary hangover counter, see subclause 5.2.7 number of subframes in current frame meeting periodicity criterion, see subclause 5.2.9 previous value of dm, see subclause 5.2.4 the open loop long term predictor lags for the four speech encoder subframes numerator of left hand side of equation 8 in
36、annex C, see subclause 5.2.5 previous value of lagcount, see subclause 5.2.9 fourth order short term prediction error, see subclause 5.2.5 Boolean flag indicating the presence of a periodic signal component, see subclause 5.2.9 energy in the current filtered signal frame, see subclause 5.2.1 autocor
37、relation vector obtained from avl , see subclause 5.2.3 the first four unquantized reflection coefficients calculated in the speech encoder (GSM 06.20 (ETS 300 581-2) 2) autocorrelation vector of the adaptive filter predictor values, see subclause 5.2.6 difference between consecutive lag values, see
38、 subclause 5.2.9 Boolean flag indicating that the frequency spectrum of the input signal is stationary, see subclause 5.2.4 adaptive primary VAD threshold, see subclause 5.2.6 Boolean flag indicating the presence of an information tone, see subclause 5.2.5 Boolean VAD decision with hangover included
39、, see subclause 5.2.8 previous value of oldlagcount, see subclause 5.2.9 Boolean VAD decision before hangover, see subclause 5.2.7 (GSM 06.20 (ETS 300 581-2) 2.) number of frames of hangover for secondary VAD, see subclause 5.2.6 minimum length of speech burst to which hangover is added, see subclau
40、se 5.2.8 determines rate of decrease in adaptive threshold, see subclause 5.2.6 determines steady state adaptive threshold, see subclause 5.2.6 number of frames over which avo and avl are calculated, see subclause 5.2.2 threshold for pole frequency decision, see subclause 5.2.5 number of frames of h
41、angover for primary VAD, see subclause 5.2.8 determines rate of increase in adaptive threshold, see subclause 5.2.6 lag difference threshold for periodicity decision, see subclause 5.2.9 determines upper limit for adaptive threshold, see subclause 5.2.6 frame count threshold for periodicity decision
42、, see subclause 5.2.9 lower limit for adaptive threshold, see subclause 5.2.6 threshold for short tem prediction error, see subclause 5.2.5 energy threshold, see subclause 5.2.6 decision threshold for evaluation of stat flag, subclause 5.2.4 DIN1 DIN ETS 300583-6 96 2794442 0577115 8T1 Page 9 ETS 30
43、0 5816: November 1995 (06.42 version 4.1.1) 3.2.3 Functions + addition subtraction multiplication I division 1x1 absolute value of x AND Boolean AND OR Boolean OR b MU LT(x(i) i=a the product of the series x(i) for =a to b b SUM(x(i) i=a the sum of the series x(i) for =a to b 3.3 Abbreviations ACF A
44、utocorrelation Function AFAT ANSI American National Standards Institute DTX Discontinuous Transmission LTP Long Tem Predictor TX Transmission VAD Voice Activity Detector For abbreviations not given in this subclause see GSM O1 .o4 (ETR 100) 111 Autocorrelation Fixed point LAttice Technique DIN1 DIN
45、ETS 300583-6 96 = 2774442 0577LLb 738 Page 10 ETS 300 5816: November 1995 (06.42 version 4.1.1) 4 General The function of the VAD is to indicate whether each 20 ms frame produced by the speech encoder contains speech or not. The output is a Boolean flag (vadflag) which is used by the Transmit (TX) D
46、TX handler defined in GSM 06.41 (ETS 300 581-5) 4. This ETS is organised as follows: Clause 5 describes the principles of operation of the VAD. Clause 6 provides an overview of the computational description of the VAD. The computational details necessary for the fixed point implementation of the VAD
47、 algorithm are given in the form of an American National Standards Institute (ANSI) C program contained in GSM 06.06 (ETS 300 581-7) 5. The verification of the VAD is based on the use of digital test sequences which are described in GSM 06.07 (ETS 300 581-8) 6. The performance of the VAD algorithm i
48、s characterised by the amount of audible speech clipping it introduces and the percentage activity it indicates. The characteristics for the VAD defined in this ETS have been established by extensive testing under a wide range of operating conditions. The results are summarised in annex A. 5 Functio
49、nal description The purpose of this clause is to give the reader an understanding of the principles of operation of the VAD, whereas GSM 06.06 (ETS 300 581-7) 5 contains the fixed point computational description of the VAD. In the case of discrepancy between the two descriptions, the description in GSM 06.06 (ETS 300 581-7) 5 will prevail. 5.1 Overview and principles of operation The function of the VAD is to distinguish between noise with speech present and noise without speech present. This is achieved by comparing the energy of a filtered versio
