1、 IEC TR 63079 Edition 1.0 2017-04 TECHNICAL REPORT Code of practice for hearing-loop systems(HLS)IEC T R 63079:2017-04(en)colourinside THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2017 IEC,Geneva,Switzerland All rights reserved.Unless otherwise specified,no part of this publication may be repro
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10、fur ther assistance,plea se contact the Customer Ser v ice Centre:csciec.ch.IEC TR 63079 Edition 1.0 2017-04 TECHNICAL REPORT Code of practice for hearing-loop systems(HLS)INT ERNAT IONAL ELECT ROT ECHNICAL COMMISSION ICS 17.140.50 ISBN 978-2-8322-4154-7 Registered t rademark of the Internat ional E
11、lectrotechnica l Commission Warning!Mak e sure that you obtained this publication from an authorized distributor.colourinside 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
12、 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 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 to
13、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.16 5.4 Profess
14、ional(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 specification.17 8.2 Verif
15、ying 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 magnetic field.22 10.3.3 Uniformity of th
16、e 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 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-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
