1、 IEC 60268-7Edition 3.0 2010-01INTERNATIONAL STANDARD Sound system equipment Part 7:Headphones and earphones IEC 60268-7:2010(E)LICENSED TO MECON LIMITED-RANCHI/BANGALORE,FOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2010 IEC,
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9、TERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.IEC 60268-7Edition 3.0 2010-01INTERNATIONAL STANDARD Sound system equipment Part 7:Headphones and earphones INTERNATIONAL ELECTROTECHNICAL COMMISSION XICS 33.160.50 PRICE CODEISBN 2-8318-1073-4 Registered trademark of the International
10、Electrotechnical Commission LICENSED TO MECON LIMITED-RANCHI/BANGALORE,FOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.2 60268-7 IEC:2010(E)CONTENTS FOREWORD.4 1 Scope.6 2 Normative references.6 3 Terms and definitions.7 4 Classification,designation and coding.9 5 Marking of te
11、rminals,controls and polarity.13 6 User instructions.13 7 Conditions for specifications and measurements.14 7.1 Rated conditions.14 7.2 Standard conditions for measurement.15 7.3 Couplers and ear simulators.15 7.4 Measurement conditions for simulated programme signal.15 7.5 Loudness comparison condi
12、tions.16 7.5.1 General.16 7.5.2 Free-field comparison conditions.16 7.5.3 Diffuse-field comparison conditions.17 7.6 Ear canal sound pressure level measurement conditions.17 8 Characteristics to be specified and their methods of measurement.17 8.1 Power supply.17 8.2 Electrical impedance.17 8.2.1 Ra
13、ted impedance.17 8.2.2 Impedance/frequency characteristic.18 8.2.3 Rated source impedance.18 8.3 Input voltage.18 8.3.1 Rated source e.m.f.18 8.3.2 Limiting values of input voltage.18 8.3.3 Characteristic voltage.19 8.3.4 Simulated programme signal characteristic voltage.20 8.3.5 Simulated programme
14、 signal characteristic voltage corrected by A-weighting characteristics and free-field response compensation.20 8.3.6 Protective devices.21 8.4 Input power.21 8.5 Sound pressure(level).22 8.5.1 General.22 8.5.2 Characteristics to be specified.22 8.5.3 Method of measurement.22 8.6 Frequency response.
15、23 8.6.1 General.23 8.6.2 Coupler or ear simulator(including HATS)frequency response.23 8.6.3 Free-field comparison frequency response.24 8.6.4 Diffuse-field comparison frequency response.25 8.6.5 Free-field and diffuse-field ear canal sound pressure level frequency responses.25 8.6.6 Rated frequenc
16、y range.27 8.7 Amplitude non-linearity.27 8.7.1 General.27 LICENSED TO MECON LIMITED-RANCHI/BANGALORE,FOR INTERNAL USE AT THIS LOCATION ONLY,SUPPLIED BY BOOK SUPPLY BUREAU.60268-7 IEC:2010(E)3 8.7.2 Harmonic distortion.27 8.7.3 Modulation distortion.28 8.7.4 Difference-frequency distortion.28 8.8 Rated climatic conditions.29 8.9 External electric and/or magnetic field.29 8.9.1 Characteristics to be specified.29 8.9.2 Method of measurement.29 8.10 Unwanted sound radiation.29 8.10.1 Characteristic