1、Code of practice for hearing-loop systems (HLS) PD IEC/TR 63079:2017 BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06IEC TR 63079 Edition 1.0 2017-04 TECHNICAL REPORT Code of practice for hearing-loop systems (HLS) IEC TR 63079:2017-04(en) colour inside National for
2、eword This Published Document is the UK implementation of IEC/TR 63079:2017. The UK participation in its preparation was entrusted to Technical Committee EPL/29, Electroacoustics. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does
3、 not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017 ISBN 978 0 580 95746 8 ICS 17.140.50 Compliance with a British Standard cannot confer immunity from le
4、gal obligations. This Published Document was published under the authority of the Standards Policy and Strategy Committee on 30 September 2017. Amendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD IEC/TR 63079:2017 IEC TR 63079 Edition 1.0 2017-04 TECHNICAL REPORT
5、Code of practice for hearing-loop systems (HLS) IEC TR 63079:2017-04(en) colour inside PD IEC/TR 63079:2017 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2017 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in an
6、y form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or IECs member National Committee in the country of the requester. If you have any questions about IEC copyright or have an enquiry about obtaining additional rights
7、to this publication, please contact the address below or your local IEC member National Committee for further information. IEC Central Office Tel.: +41 22 919 02 11 3, rue de Varemb Fax: +41 22 919 03 00 CH-1211 Geneva 20 infoiec.ch Switzerland www.iec.ch About the IEC The International Electrotechn
8、ical Commission (IEC) is the leading global organization that prepares and publishes International Standards for all electrical, electronic and related technologies. About IEC publications The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you h
9、ave the latest edition, a corrigenda or an amendment might have been published. IEC Catalogue - webstore.iec.ch/catalogue The stand-alone application for consulting the entire bibliographical information on IEC International Standards, Technical Specifications, Technical Reports and other documents.
10、 Available for PC, Mac OS, Android Tablets and iPad. IEC publications search - www.iec.ch/searchpub The advanced search enables to find IEC publications by a variety of criteria (reference number, text, technical committee,). It also gives information on projects, replaced and withdrawn publications
11、. IEC Just Published - webstore.iec.ch/justpublished Stay up to date on all new IEC publications. Just Published details all new publications released. Available online and also once a month by email. Electropedia - www.electropedia.org The worlds leading online dictionary of electronic and electric
12、al terms containing 20 000 terms and definitions in English and French, with equivalent terms in 16 additional languages. Also known as the International Electrotechnical Vocabulary (IEV) online. IEC Glossary - std.iec.ch/glossary 65 000 electrotechnical terminology entries in English and French ext
13、racted from the Terms and Definitions clause of IEC publications issued since 2002. Some entries have been collected from earlier publications of IEC TC 37, 77, 86 and CISPR. IEC Customer Service Centre - webstore.iec.ch/csc If you wish to give us your feedback on this publication or need further as
14、sistance, please contact the Customer Service Centre: csciec.ch. PD IEC/TR 63079:2017 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2017 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means
15、, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or IECs member National Committee in the country of the requester. If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication, p
16、lease contact the address below or your local IEC member National Committee for further information. IEC Central Office Tel.: +41 22 919 02 11 3, rue de Varemb Fax: +41 22 919 03 00 CH-1211 Geneva 20 infoiec.ch Switzerland www.iec.ch About the IEC The International Electrotechnical Commission (IEC)
17、is the leading global organization that prepares and publishes International Standards for all electrical, electronic and related technologies. About IEC publications The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the latest edition
18、, a corrigenda or an amendment might have been published. IEC Catalogue - webstore.iec.ch/catalogue The stand-alone application for consulting the entire bibliographical information on IEC International Standards, Technical Specifications, Technical Reports and other documents. Available for PC, Mac
19、 OS, Android Tablets and iPad. IEC publications search - www.iec.ch/searchpub The advanced search enables to find IEC publications by a variety of criteria (reference number, text, technical committee,). It also gives information on projects, replaced and withdrawn publications. IEC Just Published -
20、 webstore.iec.ch/justpublished Stay up to date on all new IEC publications. Just Published details all new publications released. Available online and also once a month by email. Electropedia - www.electropedia.org The worlds leading online dictionary of electronic and electrical terms containing 20
21、 000 terms and definitions in English and French, with equivalent terms in 16 additional languages. Also known as the International Electrotechnical Vocabulary (IEV) online. IEC Glossary - std.iec.ch/glossary 65 000 electrotechnical terminology entries in English and French extracted from the Terms
22、and Definitions clause of IEC publications issued since 2002. Some entries have been collected from earlier publications of IEC TC 37, 77, 86 and CISPR. IEC Customer Service Centre - webstore.iec.ch/csc If you wish to give us your feedback on this publication or need further assistance, please conta
23、ct the Customer Service Centre: csciec.ch. IEC TR 63079 Edition 1.0 2017-04 TECHNICAL REPORT Code of practice for hearing-loop systems (HLS) INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 17.140.50 ISBN 978-2-8322-4154-7 Registered trademark of the International Electrotechnical Commission Warning! M
24、ake sure that you obtained this publication from an authorized distributor. colour inside PD IEC/TR 63079:2017 2 IEC TR 63079:2017 IEC 2017 CONTENTS FOREWORD . 7 INTRODUCTION . 9 1 Scope 10 2 Normative references 10 3 Terms, definitions, signs and symbols . 10 3.1 Terms and definitions 10 3.2 Signs
25、and symbols 12 3.2.1 Symbol for an induction-loop . 12 3.2.2 Symbol for multiple loops . 12 3.2.3 Sign for display in premises where an HLS is installed and for HLS equipment identification . 13 3.2.4 Identification of areas where reception of the HLS is not satisfactory . 13 4 General . 14 4.1 How
26、to use this document . 14 4.1.1 Persons addressed 14 4.1.2 Objectives . 14 4.2 Specialist advice . 15 4.3 Safety aspects 15 4.4 Conforming to existing performance documents 15 5 Technical advice 15 5.1 Complying with this document . 15 5.2 Seeking technical advice . 15 5.3 The nature of the advice .
27、 16 5.4 Professional (consultancy) advice . 16 6 Purpose of the system . 16 7 Choosing the system supplier 16 7.1 General . 16 7.2 Approaching a contractor 17 7.3 Approaching a manufacturer of HLS equipment 17 7.4 Approaching a specialist consultant 17 8 Contractual provisions . 17 8.1 Performance s
28、pecification . 17 8.2 Verifying that the completed system delivers its intended performance . 17 8.3 Arbitration . 18 9 Classification of systems . 18 10 Design . 20 10.1 General . 20 10.2 Symbols 20 10.3 Basic theory 21 10.3.1 Production of a magnetic field 21 10.3.2 Directional pattern of the magn
29、etic field . 22 10.3.3 Uniformity of the magnetic field strength 26 10.3.4 Reference points for magnetic field strength . 26 10.3.5 Relationship between the requirements of IEC 60118-4 and the characteristics of hearing aids and speech signals 27 10.3.6 Impedance of the loop . 28 PD IEC/TR 63079:201
30、7 2 IEC TR 63079:2017 IEC 2017 CONTENTS FOREWORD . 7 INTRODUCTION . 9 1 Scope 10 2 Normative references 10 3 Terms, definitions, signs and symbols . 10 3.1 Terms and definitions 10 3.2 Signs and symbols 12 3.2.1 Symbol for an induction-loop . 12 3.2.2 Symbol for multiple loops . 12 3.2.3 Sign for di
31、splay in premises where an HLS is installed and for HLS equipment identification . 13 3.2.4 Identification of areas where reception of the HLS is not satisfactory . 13 4 General . 14 4.1 How to use this document . 14 4.1.1 Persons addressed 14 4.1.2 Objectives . 14 4.2 Specialist advice . 15 4.3 Saf
32、ety aspects 15 4.4 Conforming to existing performance documents 15 5 Technical advice 15 5.1 Complying with this document . 15 5.2 Seeking technical advice . 15 5.3 The nature of the advice . 16 5.4 Professional (consultancy) advice . 16 6 Purpose of the system . 16 7 Choosing the system supplier 16
33、 7.1 General . 16 7.2 Approaching a contractor 17 7.3 Approaching a manufacturer of HLS equipment 17 7.4 Approaching a specialist consultant 17 8 Contractual provisions . 17 8.1 Performance specification . 17 8.2 Verifying that the completed system delivers its intended performance . 17 8.3 Arbitrat
34、ion . 18 9 Classification of systems . 18 10 Design . 20 10.1 General . 20 10.2 Symbols 20 10.3 Basic theory 21 10.3.1 Production of a magnetic field 21 10.3.2 Directional pattern of the magnetic field . 22 10.3.3 Uniformity of the magnetic field strength 26 10.3.4 Reference points for magnetic fiel
35、d strength . 26 10.3.5 Relationship between the requirements of IEC 60118-4 and the characteristics of hearing aids and speech signals 27 10.3.6 Impedance of the loop . 28 IEC TR 63079:2017 IEC 2017 3 10.3.7 Selection of the method of driving the loop 29 10.3.8 Current-driven loop 29 10.3.9 Voltage-
36、driven loop 30 10.3.10 Voltage-driven loop with high-level equalization . 31 10.3.11 Voltage-driven loop with low-level equalization 33 10.3.12 Use of transformers . 33 10.3.13 Effects of building construction 34 10.3.14 Electromagnetic compatibility (EMC) . 35 10.3.15 Tone signals 37 10.3.16 Equali
37、zation, other than for compensating loop impedance characteristics . 37 10.3.17 Multiple loops 37 10.3.18 Protection of loop conductors 40 10.3.19 Automatic gain control (AGC), compression, limiting, noise gating and voice control 40 10.3.20 Signal-to-noise ratio 41 10.3.21 HLS for purposes other th
38、an assisted hearing . 42 10.4 System components 42 10.4.1 Final amplifiers 42 10.4.2 Preamplifiers and mixers . 42 10.4.3 Signal sources . 43 10.5 Objective measurement of intelligibility . 50 10.6 Safety and reliability considerations 51 10.7 Designing for monitoring and maintenance 51 10.8 Externa
39、l factors . 51 10.8.1 Magnetic noise interference . 51 10.8.2 Effect of metal in the building 52 10.9 Magnetic field overspill . 52 10.10 The role of the system designer in commissioning 52 11 Responsibility of the installer . 52 12 Installation practices and workmanship 54 13 Inspection and testing
40、 of wiring . 55 14 Commissioning 56 15 Documentation 57 16 Certification . 58 17 Acceptance 59 18 Verification 60 19 Owner responsibilities . 60 19.1 Signage 60 19.2 User feedback . 61 19.3 Staff training . 61 20 Operation and maintenance . 61 20.1 General . 61 20.2 Routine testing 61 20.3 Inspectio
41、n and servicing . 62 20.4 Non-routine attention 63 20.5 Special inspection on appointment of a new maintenance organization . 63 20.6 Arrangements for repair of faults or damage . 63 PD IEC/TR 63079:2017 4 IEC TR 63079:2017 IEC 2017 20.7 Modifications to the system . 63 21 User responsibilities 64 2
42、1.1 Responsible person 64 21.2 Logbook 65 Annex A (informative) HLS monitoring receivers . 66 A.1 General . 66 A.2 Recommendations for fixed receivers 66 A.3 Recommendations for portable receivers 67 Annex B (informative) What is a hearing-loop system (HLS) and how does it work? . 68 B.1 General . 6
43、8 B.2 Benefits of HLS (for hearing enhancement) . 68 B.3 Limitations of HLS . 69 Annex C (informative) Explanations of the basis of the design formulas . 70 C.1 Magnetic field strength 70 C.1.1 Magnetic field strength produced by an element of conductor 70 C.1.2 Field strength produced by a circular
44、 loop at a point on its axis . 70 C.2 Magnetic field strength at the centre of a rectangular loop 72 C.3 Magnetic field strength at an arbitrary point 73 C.4 Loop conductor sizes and resistances . 78 C.4.1 General . 78 C.4.2 Resistance of the loop conductor and relation between conductor size and cu
45、t-off frequency for a voltage-driven loop 78 C.4.3 Quick reference tables (derived from IEC 60228) . 79 C.4.4 Inductance of two parallel wires, leading to the inductance of a rectangular loop . 79 C.4.5 Variation of the impedance of a loop of fixed dimensions with conductor resistance 82 C.4.6 High-
46、level equalizer . 82 Annex D (informative) Explanation of the specification and measurement of magnetic field strength of induction-loop systems 85 Annex E (normative) Specification of the PPM-based field strength meter 87 E.1 General . 87 E.2 Checking magnetic field strength meters . 88 Annex F (in
47、formative) Magnetic field direction near the loop conductor 89 Annex G (informative) Direct-to-reverberant sound pressure ratio 91 Annex H (informative) Model certificates 92 H.1 Design certificate 92 H.2 Installation certificate 93 H.3 Commissioning certificate . 94 H.4 Acceptance certificate . 96
48、H.5 Verification certificate (optional) 97 H.6 Inspection and servicing certificate . 98 H.7 Modification certificate 100 Bibliography 102 Figure 1 Symbol for use on diagrams . 12 Figure 2 Symbol for multiple loops for use on diagrams . 13 PD IEC/TR 63079:2017 4 IEC TR 63079:2017 IEC 2017 20.7 Modif
49、ications to the system . 63 21 User responsibilities 64 21.1 Responsible person 64 21.2 Logbook 65 Annex A (informative) HLS monitoring receivers . 66 A.1 General . 66 A.2 Recommendations for fixed receivers 66 A.3 Recommendations for portable receivers 67 Annex B (informative) What is a hearing-loop system (HLS) and how does it work? . 68 B.1 General . 68 B.2 Benefits of HLS (for hearing enhancement) . 68 B.3 Limitations of HLS . 69 Annex C (informative) Explanations of the basis of the design formulas . 70 C.1 Magnetic field strengt
