IEC 60645-3:2020

IEC 60645-3 ®
Edition 3.0 2020-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electroacoustics – Audiometric equipment –
Part 3: Test signals of short duration

Électroacoustique – Appareils audiométriques –
Partie 3: Signaux d'essai de courte durée

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IEC 60645-3 ®
Edition 3.0 2020-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electroacoustics – Audiometric equipment –

Part 3: Test signals of short duration

Électroacoustique – Appareils audiométriques –

Partie 3: Signaux d'essai de courte durée

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.140.50 ISBN 978-2-8322-8901-3

– 2 – IEC 60645-3:2020 © IEC 2020
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Reference signals . 10
4.1 General . 10
4.2 Reference click . 11
4.3 Reference tone-burst . 11
4.4 Reference broadband chirp . 12
4.5 Reference octave-band chirps . 12
5 Calibration and measurement of short-duration signals . 13
BibIiography . 14

Figure 1 – Basic specification of an electrical reference click . 7
Figure 2 – Illustration of the method of measurement of peak-to-peak equivalent signal
levels . 8
Figure 3 – Temporal characteristics of an electrical reference tone-burst . 8
Figure 4 – Time domain specification of the electrical reference click . 11
Figure 5 – Temporal characteristics of the electrical reference broadband chirp. 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROACOUSTICS – AUDIOMETRIC EQUIPMENT –

Part 3: Test signals of short duration

FOREWORD
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International Standard IEC 60645-3 has been prepared by IEC technical committee 29:
Electroacoustics.
This third edition cancels and replaces the second edition published in 2007. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) new figures of reference signals;
b) changes in definitions.
– 4 – IEC 60645-3:2020 © IEC 2020
The text of this International Standard is based on the following documents:
FDIS Report on voting
29/1066/FDIS 29/1070/RVD
Full information on the voting for the approval of this document can be found in the report on
voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 60645 series, under the general title Electroacoustics – Audiometric
equipment, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the document will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
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INTRODUCTION
Developments in the field of hearing measurements for diagnostic, hearing conservation and
rehabilitation purposes have resulted in the availability of a wide range of audiometric
equipment. In addition, it is possible to consider audiometric equipment in terms of a set of
functional units that can be specified independently. By specifying these functional units, it is
then possible to specify the performance of other audiometric equipment that uses these units.
The IEC 60645 series consists of a number of parts. IEC 60645-3 covers the requirements for
reference and other test signals of short duration.
Examples of test methods, where such signals are commonly used, are the recording of auditory
evoked potentials and evoked otoacoustic emissions. Reference signals are described in order
to provide a basis for calibration and as a recommendation for use when there is no specific
reason to have an alternative signal. Measurement methods for short duration acoustic and
vibratory test signals are described.

– 6 – IEC 60645-3:2020 © IEC 2020
ELECTROACOUSTICS – AUDIOMETRIC EQUIPMENT –

Part 3: Test signals of short duration

1 Scope
This part of IEC 60645 specifies a means of describing the physical characteristics, in terms of
electrical waveforms, of audiometric reference and test signals of short duration and methods
for thei
...