ETSI EN 301 706-1999 Digital Cellular Telecommunications System (Phase 2+) Comfort Noise Aspects for Adaptive Multi-Rate (AMR) Speech Traffic Channels (GSM 06 92 Version 7 1 1 Rele.pdf
《ETSI EN 301 706-1999 Digital Cellular Telecommunications System (Phase 2+) Comfort Noise Aspects for Adaptive Multi-Rate (AMR) Speech Traffic Channels (GSM 06 92 Version 7 1 1 Rele.pdf》由会员分享,可在线阅读,更多相关《ETSI EN 301 706-1999 Digital Cellular Telecommunications System (Phase 2+) Comfort Noise Aspects for Adaptive Multi-Rate (AMR) Speech Traffic Channels (GSM 06 92 Version 7 1 1 Rele.pdf(13页珍藏版)》请在麦多课文档分享上搜索。
1、 STD-ETSI EN 301 7Ob-ENGL 1999 3400855 04834L3 7b4 ETSI EN 301 706 V7.1.1 (1999-12) European Standard (Telecommunications series) Digital cellular telecommunication system (Phase 2+); Comfort noise aspects for Adaptive Multi-Rate (AMR) speech traffic channels (GSM 06.92 version 7.1 .I Release 1998)
2、STD-ETSI EN 303 706-ENGL 1999 = 3400855 0483434 bTO (GSM 06.92 version 7.1.1 Release 1998) 2 ETSI EN 301 706 V7.1.1 (1999-12) Reference DENISMG-1 10692Q7 Keywords Digital cellular telecommunications system, Global System for Mobile communications (GSM) ETSI Postal address F-O6921 Sophia Antipolis Ce
3、dex - FRANCE Ofice address 650 Route des Lucioles - Sophia Antipolis Valbonne - FRANCE Siret N“ 348 623 562 00017 - NAF 742 C Association a but non lucratif enregistree a la Sous-Prefecture de Grasse (06) No 7803/88 Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 Internet secretariatetsi.fr Individua
4、l copies of this ETSI deliverable can be downloaded from http:/www.etsi.org If you find errors in the present document, send your comment to: editoretsi.fr Important notice This ETSI deliverable may be made available in more than one electronic version or in print. In any case of existing or perceiv
5、ed difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Copyright Notification No part may be re
6、produced except as authorized by written permission. The copyright and the foregoing resriction extend to reproduction in all media. O European Telecommunications Standards Institute 1999. AU rights reserved. STD-ETSI EN 301 70b-ENGL 1999 = 3400655 0483415 531 m (GSM 06.92 verslon 7.1.1 Release 1998
7、) 3 ETSI EN 301 706 V7.1.1 (1999-12) Content intellectual Property Rights 4 Foreword . 4 1 2 3 3.1 3.2 3.3 4 5 5.1 5.2 5.3 5.4 6 6.1 6.2 7 Scope 5 References 5 Definitions, symbols and abbreviations . 5 5 6 Abbreviations . 6 General . 7 Functions on the transmit (TX) side 7 LSF evaluation 7 Frame en
8、ergy calculation 8 Modification of the speech encoding algorithm during SID frame generation . 8 SID-fhne encoding . 9 Functions on the receive (RX) side 9 Averaging and decoding ofthe LP and energy parameters 9 Comfort noise generation and updating 10 Computational details and bit allocation 11 Ann
9、ex A (informative): Document change history 12 History 13 STD.ETS1 EN 301 70b-ENGL 1999 M 3400855 04834Lb 473 (GSM 06.92 version 7.1.1 Release 1998) 4 ETSI EN 301 706 V7.1.1 (1999-12) intellectual Property Rights IPRS essential or potentially essential to the present document may have been declared
10、to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in SR O00 3 14: TnteIectuaI Propers. Rights (IPRs); Essential. or potentially Essential. IPRs notified to ETSIin respect of ETSZstandards”, which is available
11、 Abbreviations and acronyms“. GSM 06.73: “Digital cellular telecommunications system (Phase 2+); ANSI-C code for the GSM Adaptive Multi-Rate speech codec“. GSM 06.90: “Digital cellular telecommunications system (Phase 2+); Adaptive Multi-Rate speech transcoding“. GSM 06.91: “Digital cellular telecom
12、munications system (Phase 2+); Substitution and muting of lost frame for Adaptive Multi-Rate speech traffic channels“. GSM 06.93: “Digital cellular telecommunications system (Phase 2+); Discontinuous transmission (DTX) for Adaptive Multi-Rate speech traffic channels“. 3 1 41 51 3 3.1 Def i nit ions
13、, symbols and ab brevi at i on s Definit ions For the purpose of the present document, the following terms and definitions apply. Frame: time interval of 20 ms corresponding to the time segmentation of the adaptive multi-rate speech transcoder, also used as a short term for traffic frame. (GSM 06.92
14、 version 7.1.1 Release 1998) 6 ETSI EN 301 706 V7.1.1 (1999-12) SID frames: special SID (Silence Descriptor) frames. It may convey information on the acoustic background noise or inform the decoder that it should start generating background noise. Speech frame: traffic frame that cannot be classifie
15、d as a SID frame. VAD flag: voice Activity Detection flag. TX-TYPE: one of SPEECH, SIDFIRST, SID-UPD, NO-DATA (defined in GSM 06.93). RX-TYPE: classification of the received traffic frame (defined in GSM 06.93). Other definitions of terms used in the present document can be found in GSM 06.90 3 and
16、GSM 06.93 5. The overall operation of DTX is described in GSM 06.93 5. 3.2 Symbols For the purpose of the present document, the following symbols apply. Boldface symbols are used for vector variables. f = f, f, . A, Unquantized LSF vector i = f, f2 . . . Ao Quantized LSF vector f m) i m) f meun enlo
17、, Logarithmic frame energy enly Averaged logarithmic he energy E ref e e Unquantized LSF vector of he m Quantized LSF vector of he m Averaged LSF parameter vector Reference vector for LSF quantization Computed LSF parameter prediction residual Quantized LSF parameter prediction residual cxc., = x(a)
18、 + x(a + 1) + . . . + x(b - 1) + x(b) n=u 3.3 Abbreviations For the purpose of the present document, the following abbreviations apply. AMR BSS DTX MS SID LP LSP LSF Rx TX VAD Adaptive Multi-Rate Base Station Subsystem Discontinuous Transmission Mobile Station SIlence Descriptor Linear Prediction Li
19、ne Spectral Pair Line Spectral Frequency Receive Transmit Voice Activity Detector For abbreviations not given in this subclause, see GSM 01.04 i. STDmETSI EN 301 70b-ENGL 1999 3400855 0483419 182 (GSM 06.92 version 7.1.1 Release 1998) 7 ETSI EN 301 706 V7.1.1 (1999-12) 4 General A basic problem when
20、 using DTX is that the background acoustic noise, which is transmitted together with the speech, would disappear when the radio transmission is cut, resulting in discontinuities of the background noise. Since the DTX switching can take place rapidly, it has been found that this effect can be very an
21、noying for the listener - especially in a car environment with high background noise levels. In bad cases, the speech may be hardly intelligible. The present document specifies the way to overcome this problem by generating on the receive (U) side synthetic noise similar to the transmit (TX) side ba
22、ckground noise. The comfort noise parameters are estimated on the TX side and transmitted to the RX side before the radio transmission is switched off and at a regular rate afterwards. This allows the comfort noise to adapt to the changes of the noise on the TX side. 5 Functions on the transmit (TX)
23、 side The comfort noise evaluation algorithm uses the following parameters of the AMR speech encoder, defined in GSM 06.90 3: - the unquantized Linear Prediction (LP) parameters, using the Line Spectral Pair (LSP) representation, where the unquantized Line Spectral Frequency (LSF) vector is given by
24、 f = J f2 . . . A, ; the unquantized LSF vector for the 12.2 kbis mode is given by the second set of LSF parameters in the frame. - The algorithm computes the following parameters to assist in comfort noise generation: - the averaged LSF parameter vector f me?n (average of the LSF parameters of the
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
本资源只提供5页预览,全部文档请下载后查看!喜欢就下载吧,查找使用更方便
10000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ETSIEN3017061999DIGITALCELLULARTELECOMMUNICATIONSSYSTEMPHASE2COMFORTNOISEASPECTSFORADAPTIVEMULTIRATEAMRSPEECHTRAFFICCHANNELSGSM0692VERSION711RELEPDF

链接地址:http://www.mydoc123.com/p-729801.html