IEC_61603-7-2003.pdf

INTERNATIONALSTANDARDIEC61603-7First edition2003-05Transmission systems of audio and/or video andrelated signals using infra-red radiation Part 7:Digital audio signals for conference andsimilar applicationsReference numberIEC 61603-7:2003(E)LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.Publication numberingAs from 1 January 1997 all IEC publications are issued with a designation in the60000 series.For example,IEC 34-1 is now referred to as IEC 60034-1.Consolidated editionsThe IEC is now publishing consolidated versions of its publications.For example,edition numbers 1.0,1.1 and 1.2 refer,respectively,to the base publication,thebase publication incorporating amendment 1 and the base publication incorporatingamendments 1 and 2.Further information on IEC publicationsThe technical content of IEC publications is kept under constant review by the IEC,thus ensuring that the content reflects current technology.Information relating tothis publication,including its validity,is available in the IEC Catalogue ofpublications(see below)in addition to new editions,amendments and corrigenda.Information on the subjects under consideration and work in progress undertakenby the technical committee which has prepared this publication,as well as the listof publications issued,is also available from the following:IEC Web Site(www.iec.ch)Catalogue of IEC publicationsThe on-line catalogue on the IEC web site(http:/www.iec.ch/searchpub/cur_fut.htm)enables you to search by a variety of criteria including text searches,technicalcommittees and date of publication.On-line information is also available onrecently issued publications,withdrawn and replaced publications,as well ascorrigenda.IEC Just Published This summary of recently issued publications(http:/www.iec.ch/online_news/justpub/jp_entry.htm)is also available by email.Please contact the CustomerService Centre(see below)for further information.Customer Service CentreIf you have any questions regarding this publication or need further assistance,please contact the Customer Service Centre:Email:custserviec.chTel:+41 22 919 02 11Fax:+41 22 919 03 00LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.INTERNATIONALSTANDARDIEC61603-7First edition2003-05Transmission systems of audio and/or video andrelated signals using infra-red radiation Part 7:Digital audio signals for conference andsimilar applications IEC 2003 Copyright-all rights reservedNo part of this publication may be reproduced or utilized in any form or by any means,electronic ormechanical,including photocopying and microfilm,without permission in writing from the publisher.International Electrotechnical Commission,3,rue de Varemb,PO Box 131,CH-1211 Geneva 20,SwitzerlandTelephone:+41 22 919 02 11 Telefax:+41 22 919 03 00 E-mail:inmailiec.ch Web:www.iec.chUFor price,see current cataloguePRICE CODECommission Electrotechnique InternationaleInternational Electrotechnical Commission LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.2 61603-7 IEC:2003(E)CONTENTSFOREWORD.41Scope.52Normative references.53Terms and definitions.54Abbreviations.55Explanation of terms and general information.66System considerations.67Basic system concept.68Protocol.78.1System context.78.2Physical layer.88.3Data link layer.138.4Detailed overview of audio frame structures.159Data protocol.179.1General.179.2Data messages.189.3Data packet structure.21Annex A(normative)Definition of prototype filter.23Annex B(informative)Example of/f diagram in the user area conference.24Annex C(informative)Provision for future developments.25Bibliography.26Figure 1 System.7Figure 2 Conceptual model.7Figure 3 Band allocation for 6 modulated sub-carriers.8Figure 4 (D)QPSK constellation and differential decoding algorithm.9Figure 5 Pulse response of a raised cosine channel filter.10Figure 6 Scrambler.11Figure 7 Block diagram of sub-band APCM encoder.12Figure 8 Quantization of sub-band samples.13Figure 9 Superframe structure.14Figure 10 RS frame structure.14Figure 11 Audio block structure.15Figure 12 CRC calculation.15Figure 13 Audio block structure for medium quality.16Figure 14 Bit-pool sample structure for medium quality.16Figure 15 Audio block structure for high quality.16Figure 16 Bit-pool sample structure for high quality.17Figure 17 Positioning of the data protocol.18LICENSED TO MECON Limited.-RANCHI/BANGALOREFOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.61603-7 IEC:2003(E)3 Figure 18 Data message build-up.18Figure 19 Configuration message structure.19Figure 20 Display message structure for ASCII display data.20Figure 21 Display message structure for bitmap display data.21Figure 22 Segmentation of data messages.21Figure 23 Data packets fitted on to the superframe structure.22Table 1 Sub-carrier centre frequencies.8Table 2 Phase transitions of the differential