1、 IEC 61938 Edition 3.0 2018-01 INTERNATIONAL STANDARD Multimedia systems Guide to the recommended characteristics of analogue interfaces to achieve interoperability IEC 61938:2018-01(en)THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2018 IEC,Geneva,Switzerland All rights reserved.Unless otherwise
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10、ion or need further assistance,please contact the Customer Service Centre:csciec.ch.IEC 61938 Edition 3.0 2018-01 INTERNATIONAL STANDARD Multimedia systems Guide to the recommended characteristics of analogue interfaces to achieve interoperability INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.160
11、.01,35.200 ISBN 978-2-8322-5056-3 Registered trademark of the International Electrotechnical Commission Warning!Make sure that you obtained this publication from an authorized distributor.2 IEC 61938:2018 IEC 2018 CONTENTS FOREWORD.5 INTRODUCTION.7 1 Scope.8 2 Normative references.10 3 Terms and def
12、initions.10 4 General conditions.13 5 Power supply.13 5.1 Alternating current(AC)power supply voltages and frequencies.13 5.2 Direct current(DC)power supply voltages.14 5.3 Power supply feed for microphones.14 6 Interconnections.14 6.1 Connections.14 6.1.1 General.14 6.1.2 Characteristics of cables.
13、14 6.2 Connectors.16 7 Marking and symbols for marking.16 7.1 Marking.16 7.2 Symbols for marking.16 8 Electrical recommended values.16 8.1 General purpose output/input.16 8.2 General purpose audio output/input.16 8.2.1 Audio-only interfaces for consumer equipment.16 8.2.2 Interfaces for professional
14、 equipment and consumer equipment where audio and video signals are present on the same connector or cable.17 8.3 General purpose video input/output.19 9 Interoperability of microphones and amplifiers.19 9.1 Microphones(excluding piezoelectric types).19 9.2 Power supply feed for electret microphones
15、 fed over a signal conductor(“plug-in power”).20 9.3 Power supply feed for electret microphones fed by a separate conductor(soundcard power or PC power).21 9.4 Phantom supply system.21 9.4.1 General.21 9.4.2 Supply voltage polarity.21 9.4.3 Circuit diagram.22 9.4.4 Value of the supply voltage.22 9.4
16、.5 Supply current.22 9.4.6 Marking.22 9.5 A-B supply system.23 9.5.1 General.23 9.5.2 Output impedance of the microphone.23 9.5.3 Circuit diagram.23 9.5.4 Connection of the power supply to earth.23 9.5.5 Marking.23 9.6 Polarity of the audio frequency voltage.23 10 Interoperability of record-playing units(pick-ups)and amplifiers.25 IEC 61938:2018 IEC 2018 3 11 Interoperability of loudspeakers and amplifiers.26 11.1 Single unit loudspeakers.26 11.2 Loudspeaker systems.26 11.2.1 Loudspeakers with b
