EN IEC 62127-1:2022

SLOVENSKI STANDARD
01-julij-2022
Nadomešča:
SIST EN 62127-1:2008
SIST EN 62127-1:2008/A1:2014
Ultrazvok - Hidrofoni - 1. del: Meritve in karakterizacija medicinskih ultrazvočnih
polj (IEC 62127-1:2022)
Ultrasonics - Hydrophones - Part 1: Measurement and characterization of medical
ultrasonic fields (IEC 62127-1:2022)
Ultraschall - Hydrophone - Teil 1: Messung und Charakterisierung von medizinischen
Ultraschallfeldern (IEC 62127-1:2022)
Ultrasons - Hydrophones - Partie 1: Mesurage et caractérisation des champs
ultrasoniques médicaux jusqu'à (IEC 62127-1:2022)
Ta slovenski standard je istoveten z: EN IEC 62127-1:2022
ICS:
11.040.01 Medicinska oprema na Medical equipment in general
splošno
17.140.50 Elektroakustika Electroacoustics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 62127-1

NORME EUROPÉENNE
EUROPÄISCHE NORM May 2022
ICS 17.140.50 Supersedes EN 62127-1:2007 + A1:2013
English Version
Ultrasonics - Hydrophones - Part 1: Measurement and
characterization of medical ultrasonic fields
(IEC 62127-1:2022)
Ultrasons - Hydrophones - Partie 1: Mesurage et Ultraschall - Hydrophone - Teil 1: Messung und
caractérisation des champs ultrasoniques médicaux Charakterisierung von medizinischen Ultraschallfeldern bis
(IEC 62127-1:2022) zu 40 MHz
(IEC 62127-1:2022)
This European Standard was approved by CENELEC on 2022-04-29. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62127-1:2022 E

European foreword
The text of document 87/783/FDIS, future edition 2 of IEC 62127-1, prepared by IEC/TC 87
"Ultrasonics" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2023-01-29
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2025-04-29
document have to be withdrawn
This document supersedes EN 62127-1:2007 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62127-1:2022 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60500 NOTE Harmonized as EN 60500
IEC 60601-2-5 NOTE Harmonized as EN 60601-2-5
IEC 60601-2-37 NOTE Harmonized as EN 60601-2-37
IEC 60601-2-62 NOTE Harmonized as EN 60601-2-62
IEC 61157 NOTE Harmonized as EN 61157
IEC 61161 NOTE Harmonized as EN 61161
IEC 61828 NOTE Harmonized as EN IEC 61828
IEC 61846 NOTE Harmonized as EN 61846
IEC 61847 NOTE Harmonized as EN 61847
IEC/TS 61949 NOTE Harmonized as CLC/TS 61949
IEC 62359 NOTE Harmonized as EN 62359
IEC 63045 NOTE Harmonized as EN IEC 63045
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60565-1 - Underwater acoustics - Hydrophones - EN IEC 60565-1 -
Calibration of hydrophones - Part 1:
Procedures for free-field calibration of
hydrophones
IEC 61689 - Ultrasonics - Physiotherapy systems - Field EN IEC 61689 -
specifications and methods of
measurement in the frequency range 0,5
MHz to 5 MHz
IEC 62127-2 - Ultrasonics - Hydrophones - Part 2: EN 62127-2 -
Calibration for ultrasonic fields up to 40
MHz
IEC 62127-3 - Ultrasonics - Hydrophones - Part 3: EN 62127-3 -
Properties of hydrophones for ultrasonic
fields up to 40 MHz
IEC 63009 - Ultrasonics - Physiotherapy systems - Field EN IEC 63009 -
specifications and methods of
measurement in the frequency range 20
kHz to 500 kHz
ISO 16269-6 - Statistical interpretation of data – Part 6: - -
Determination of statistical tolerance
intervals
ISO/IEC Guide 98-3 2008 Uncertainty of measurement - Part 3: - -
Guide to the expression of uncertainty in
measurement (GUM:1995)
IEC 62127-1 ®
Edition 2.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Ultrasonics – Hydrophones –
Part 1: Measurement and characterization of medical ultrasonic fields

Ultrasons – Hydrophones –
Partie 1: Mesurage et caractérisation des champs ultrasoniques médicaux

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.140.50 ISBN 978-2-8322-1080-1

– 2 – IEC 62127-1:2022 © IEC 2022
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 Symbols . 32
5 Measurement requirements . 34
5.1 Requirements for hydrophones and amplifiers. 34
5.1.1 Preface . 34
5.1.2 General . 34
5.1.3 Sensitivity of a hydrophone . 35
5.1.4 Directional response of a hydrophone . 35
5.1.5 Effective hydrophone size . 35
5.1.6 Choice of the size of a hydrophone active element . 35
5.1.7 Bandwidth. 37
5.1.8 Linearity . 40
5.1.9 Hydrophone signal amplifier . 40
5.1.10 Hydrophone cable length and amplifiers . 40
5.2 Requirements for positioning and water baths . 41
5.2.1 General . 41
5.2.2 Positioning systems . 41
5.2.3 Water bath . 42
5.3 Requirements for data acquisition and analysis systems . 43
5.4 Recommendations for ultrasonic equipment being characterized. 43
6 Measurement procedure . 43
6.1 General . 43
6.2 Preparation and alignment . 44
6.2.1 Preparation . 44
6.2.2 Aligning an ultrasonic transducer and a hydrophone . 44
6.3 Measurement . 44
6.4 Analysis . 44
6.4.1 Corrections for restricted bandwidth and spatial resolution . 44
6.4.2 Uncertainties . 44
7 Beam characterization . 45
7.1 General . 45
7.2 Primary pressure parameters . 46
7.2.1 General . 46
7.2.2 Peak-compressional acoustic pressure and peak-rarefactional acoustic
pressure . 47
7.2.3 Spatial-peak RMS acoustic pressure . 47
7.2.4 Local distortion parameter . 48
7.3 Intensity parameters derived from acoustic pressure . 48
7.3.1 General . 48
7.3.2 Intensity parameters using pulse-pressure-squared integral . 49
8 Requirements for specific ultrasonic fields . 52

IEC 62127-1:2022 © IEC 2022 – 3 –
8.1 General . 52
8.2 Diagnostic fields . 52
8.2.1 Simplified procedures and guidelines . 52
8.2.2 Pulsed wave diagnostic equipment . 52
8.2.3 Continuous wave diagnostic equipment . 53
8.2.4 Diagnostic equipment with low acoustic output . 54
8.3 Therapy fields . 54
8.3.1 Physiotherapy equipment. 54
8.3.2 High intensity therapeutic ultrasonic fields . 55
8.3.3 Non-focused and weakly focused pressure pulses . 55
8.4 Surgical fields . 55
8.4.1 Lithotripters and pressure pulse sources for other therapeutic purposes . 55
8.4.2 Low frequency surgical applications . 56
8.5 Fields from other medical applications . 56
9 Conformity statement. 56
9.1 General . 56
9.2 Maximum probable values . 56
9.3 Sampling. 57
Annex A (informative) General rationale. 58
Annex B (informative) Hydrophones and positioning . 60
B.1 General . 60
B.2 Electrical loading considerations . 60
B.3 Hydrophone signal amplifier . 60
B.4 Hydrophone cable length and amplifiers . 60
B.5 Transducer positioning . 61
B.6 Alignment of hydrophones . 62
B.7 Water bath lining material . 62
B.8 Recommendations for ultrasonic equipment being characterized. 62
B.9 Types of hydrophones . 63
B.9.1 Ceramic needle hydrophones . 63
B.9.2 PVDF needle hydrophones . 63
B.9.3 PVDF membrane hydrophones . 63
B.9.4 Fibre-optic and optic hydrophones . 64
B.9.5 Relative performance of different types . 65
B.10 Typical specification data for hydrophones . 65
Annex C (informative) Acoustic pressure and intensity . 66
Annex D (informative) Voltage to pressure conversion . 68
D.1 General . 68
D.2 Hydrophone deconvolution procedure . 69
D.3 Converting the data between double-sided and single-sided spectra . 70
D.4 Use of hydrophone calibration data . 72
D.4.1 Calibration data interpolation . 72
D.4.2 Calibration data extrapolation . 72
D.4.3 Regularization filtering . 73
D.5 Implication of the hydrophone deconvolution process on measurement
duration . 74
D.6 Validation of deconvolution implementation . 75
Annex E (informative) Correction for spatial averaging . 76

– 4 – IEC 62127-1:2022 © IEC 2022
E.1 Linear and quasilinear fields . 76
E.2 Linear fields, quasilinear fields, and broadband nonlinearly distorted
waveforms . 78
Annex F (informative) Acoustic output parameters for multi-mode medical ultrasonic
fields in the absence of scan-frame synchronization . 81
F.1 General . 81
F.2 Current philosophy . 81
F.3 Need for an alternative approach . 82
F.4 Proposed approach . 82
F.4.1 Alternative philosophy . 82
F.4.2 Alternative parameters . 83
F.5 Measurement methods . 84
F.5.1 General . 84
F.5.2 Peak pressures . 84
F.5.3 Temporal-average intensity . 84
F.5.4 Frequency . 85
F.5.5 Power . 85
F.6 Discussion . 85
F.6.1 Relationship to existing standards . 85
F.6.2 Advantages . 86
F.6.3 Disadvantages . 86
Annex G (informative) Propagation medium and degassing. 87
Annex H (informative) Specific ultrasonic fields . 88
H.1 Diagnostic fields . 88
H.1.1 Useful relationships between acoustical parameters . 88
H.1.2 Pulsed wave diagnostic equipment . 89
H.1.3 Continuous wave diagnostic equipment . 89
H.2 Therapy fields . 90
H.2.1 Physiotherapy equipment. 90
H.2.2 High intensity therapeutic ultrasonic equipment . 90
H.2.3 Non-focused and weakly focused pressure pulses . 90
H.3 Surgical fields . 90
H.3.1 Lithotripters . 90
H.3.2 Low frequency surgical applications . 90
Annex I (informative) Assessment of uncertainty in the acoustic quantities obtained by

hydrophone measurements . 91
I.1 General . 91
I.2 Overall (expanded) uncertainty . 91
I.3 Common sources of uncertainty . 91
Annex J (informative) Transducer and hydrophone positioning systems . 93
Annex K (informative) Beamwidth midpoint method . 94
Bibliography . 95

Figure 1 – Schematic diagram of the different planes and lines in an ultrasonic field . 12
Figure 2 – Several apertures and planes for a transducer of unknown geometry . 26
Figure 3 – Parameters for describing a focusing transducer of known geometry. 29
Figure 4 – Schematic diagram of the method of determining pulse duration . 46
Figure D.1 – A flow diagram of the hydrophone deconvolution process . 70

IEC 62127-1:2022 © IEC 2022 – 5 –
Figure D.2 – Example of waveform deconvolution . 74
Figure J.1 – Schematic diagram of the ultrasonic transducer and hydrophone degrees
of freedom . 93

Table 1 – Acoustic parameters appropriate to various types of medical ultrasonic

equipment . 45
Table B.1 – Typical specification data for hydrophones, in this case given at
1 MHz [69] . 65
Table C.1 – Properties of distilled or de-ionized water as a function of temperature [71] . 67
Table D.1 – Method of conversion from a double- to a single-sided spectrum . 71
Table D.2 – Method of conversion from a single- to a double-sided spectrum . 71
Table F.1 – Main basic parameters defined in this document or in IEC 61161 . 82
Table F.2 – List of parameters that are to be used or are to be deleted . 83
Table K.1 – Decibel beamwidth levels for determining midpoints . 94

– 6 – IEC 62127-1:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ULTRASONICS – HYDROPHONES –
Part 1: Measurement and characterization of medical ultrasonic fields

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 62127-1 has been prepared by IEC technical committee 87: Ultrasonics. It is an
International Standard.
This second edition cancels and replaces the first edition published in 2007 and
Amendment 1:2013. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition.
a) The upper frequency limit of 40 MHz has been removed.
b) Hydrophone sensitivity definitions have been changed to recognize sensitivities as complex-
valued quantities.
c) Procedures and requirements for narrow-band approximation and broadband
measurements have been modified; details on waveform deconvolution have been added.
d) Procedures for spatial averaging correction have been amended.
e) Annex D, Annex E and bibliography have been updated to support the changes of the
normative parts.
IEC 62127-1:2022 © IEC 2022 – 7 –
The text of this International Standard is based on the following documents:
Draft Report on voting
87/783/FDIS 87/788/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts of IEC 62127 series, published under the general title Ultrasonics –
Hydrophones, can be found on the IEC website.
NOTE Words in bold in the text are terms defined in Clause 3.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – IEC 62127-1:2022 © IEC 2022
INTRODUCTION
The main purpose of this document is to define various acoustic parameters that can be used
to specify and characterize ultrasonic fields propagating in liquids, and, in particular, water,
using hydrophones. Measurement procedures are outlined that may be used to determine these
parameters. Specific device related measurement standards, for example IEC 61689,
IEC 61157, IEC 61847 or IEC 62359, can refer to this document for appropriate acoustic
parameters. In IEC 62359, some additional measurement methods for attenuated parameters
and indices are described addressing the specific needs of acoustic output characterization of
ultrasonic diagnostic equipment in accordance with IEC 60601-2-37.
The philosophy behind this document is the specification of the acoustic field in terms of
acoustic pressure parameters, acoustic pressure being the primary measurement quantity when
hydrophones are used to characterize the field.
Intensity parameters are specified in this document, but these are regarded as derived
quantities that are meaningful only under certain assumptions related to the ultrasonic field
being measured.
IEC 62127-1:2022 © IEC 2022 – 9 –
ULTRASONICS – HYDROPHONES –
Part 1: Measurement and characterization of medical ultrasonic fields

1 Scope
This part of IEC 62127 specifies methods of use of calibrated hydrophones for the
measurement in liquids of acoustic fields generated by ultrasonic medical equipment including
bandwidth criteria and calibration frequency range requirements in dependence on the spectral
content of the fields to be characterized.
This document:
– defines a group of acoustic parameters that can be measured on a physically sound basis;
– defines a second group of parameters that can be derived under certain assumptions from
these measurements, and called derived intensity parameters;
– defines a measurement procedure that can be used for the determination of acoustic
pressure parameters;
– defines the conditions under which the measurements of acoustic parameters can be made
using calibrated hydrophones;
– defines procedures for correcting for limitations caused by the use of hydrophones with
finite bandwidth and finite active element size, and for estimating the corresponding
uncertainties.
NOTE 1 Throughout this document, SI units are used. In the specification of certain parameters, such as beam
areas and intensities, it can be convenient to use decimal multiples or submultiples. For example, beam area is
2 2 2
likely to be specified in cm and intensities in W/cm or mW/cm .
NOTE 2 The hydrophone as defined can be of a piezoelectric or an optic type.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60565-1, Underwater acoustics – Hydrophones – Calibration of hydrophones – Part 1:
Procedures for free-field calibration of hydrophones
IEC 61689, Ultrasonics – Physiotherapy systems – Field specifications and methods of
measurement in the frequency range 0,5 MHz to 5 MHz
IEC 62127-2, Ultrasonics – Hydrophones – Part 2: Calibration for ultrasonic fields up to 40 MHz
IEC 62127-3, Ultrasonics – Hydrophones – Part 3: Properties of hydrophones for ultrasonic
fields up to 40 MHz
IEC 63009, Ultrasonics – Physiotherapy systems – Field specifications and methods of
measurement in the frequency range 20 kHz to 500 kHz
ISO 16269-6, Statistical interpretation of data – Part 6: Determination of statistical tolerance
intervals
– 10 – IEC 62127-1:2022 © IEC 2022
ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of
uncertainty in measurement (GUM:1995)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62127-2, IEC 62127-3
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
acoustic pulse waveform
temporal waveform of the instantaneous acoustic pressure at a specified position in an
acoustic field and displayed over a period sufficiently long to include all significant acoustic
information in a single pulse or tone-burst, or one or more cycles in a continuous wave
Note 1 to entry: Temporal waveform is a representation (e.g. oscilloscope presentation or equation) of the
instantaneous acoustic pressure.
3.2
acoustic repetition period
arp
pulse repetition period for non-automatic scanning systems and the scan repetition period
for automatic scanning systems, equal to the time interval between corresponding points of
consecutive cycles for continuous wave systems
Note 1 to entry: The acoustic repetition period is expressed in seconds (s).
3.3
acoustic-working frequency
acoustic frequency
frequency of an acoustic signal based on the observation of the output of a hydrophone placed
in an acoustic field at the position corresponding to the spatial-peak temporal-peak acoustic
pressure
Note 1 to entry: The signal is analysed using either the zero-crossing acoustic-working frequency technique or
a spectrum analysis method. Acoustic-working frequencies are defined in 3.3.1, 3.3.2, 3.3.3, 3.3.4 and 3.3.5.
Note 2 to entry: In a number of cases the present definition is not very helpful or convenient, especially for
broadband transducers. In that case, a full description of the frequency spectrum is expected to be given in order
to enable any frequency-dependent correction to the signal.
Note 3 to entry: Acoustic frequency is expressed in hertz (Hz).
3.3.1
zero-crossing acoustic-working frequency
f
awf
number, n, of consecutive half-cycles (irrespective of polarity) divided by twice the time between
the commencement of the first half-cycle and the end of the n-th half-cycle
Note 1 to entry: None of the n consecutive half-cycles are expected to show evidence of phase change.
Note 2 to entry: The measurement are performed at terminals in the receiver that are as close as possible to the
receiving transducer (hydrophone) and, in all cases, before rectification.
Note 3 to entry: This frequency is determined according to the procedure specified in IEC TR 60854.
Note 4 to entry: This frequency is intended for continuous-wave systems only.

IEC 62127-1:2022 © IEC 2022 – 11 –
3.3.2
arithmetic-mean acoustic-working frequency
f
awf
arithmetic mean of the most widely separated frequencies f and f , within the range of three
1 2
times f , at which the level of the acoustic pressure spectrum is 3 dB below the peak level
Note 1 to entry: This frequency is intended for pulse-wave systems only.
Note 2 to entry: It is assumed that f < f .
1 2
Note 3 to entry: If f is not found within the range < 3f , f is to be understood as the lowest frequency above this
2 1 2
range at which the spectrum level is 3 dB below the peak level.
3.3.3
magnitude-weighted acoustic-working frequency
f
awf
frequency weighted with the spectral acoustic pressure magnitude in the frequency range where
the spectral pressure level is equal to or larger than 3 dB below the peak level
fP f df
( )  P()f if Lf() ≥−max Lf() 3dB
∫
PP
Pf() =
f = with
 (1)
awf
0 otherwise
P f df
( ) 
∫
where
f is the frequency of the acoustic pressure spectrum;
|P(f)| is the modulus of the complex-valued spectrum of the acoustic pulse waveform;
P()f
L (f) is the pressure level spectrum given from Lf( ) = 20log dB with P = 1 Pa.
P 10
P ref

P
ref

Note 1 to entry: This frequency is intended for pulse-wave systems only.
Note 2 to entry: The integrals in Formula (1) are definite, to be taken from the minimum to the maximum of the
acquired signal spectrum.
Note 3 to entry: The restriction to the range with pressure levels equal to or larger than −3 dB of the peak level is
required to avoid the influence of higher harmonic frequencies on the acoustic-working frequency.
Note 4 to entry: Definition 3.3.3 leads to more stable acoustic-working frequency results than definition 3.3.2 if
there are peaks in the acoustic pressure spectrum close to the −3 dB threshold. This is particularly relevant for the
determination of derated field parameters as required in IEC 62359 using a single derating factor depending on the
acoustic-working frequency.
3.3.4
peak pulse acoustic frequency
f
p
acoustic-working frequency of the pulse with the largest peak negative acoustic pressure
measured at the point of maximum peak negative acoustic pressure
3.3.5
temporal-average acoustic frequency
f
t
acoustic-working frequency of the time averaged acoustic pressure spectrum of the acoustic
signals measured at the point of maximum temporal-average intensity

– 12 – IEC 62127-1:2022 © IEC 2022
3.4
azimuth axis
axis formed by the junction of the azimuth plane and the source aperture plane
(measurement) or transducer aperture plane (design)
SEE: Figure 1
[SOURCE: IEC 61828:2020, 3.7]
Key
1 external transducer surface plane 7 azimuth plane, scan plane
2 source aperture plane 8 principal longitudinal plane
3 source aperture 9 longitudinal plane
4 beam area plane 10 X, azimuth axis
5 beamwidth lines 11 Y, elevation axis
6 elevation plane 12 Z, beam axis

[SOURCE: IEC 61828:2020]
Figure 1 – Schematic diagram of the different planes and lines in an ultrasonic field
3.5
azimuth plane
plane containing the beam axis and the line of the minimum full width half maximum
beamwidth
SEE: Figure 1
IEC 62127-1:2022 © IEC 2022 – 13 –
Note 1 to entry: For an ultrasonic transducer array, this is the imaging plane.
Note 2 to entry: For a single ultrasonic transducer with spherical or circular symmetry, it is any plane containing
the beam axis.
[SOURCE: IEC 61828:2020, 3.8]
3.6
bandwidth
BW
difference in the most widely separated frequencies f and f at which the level of the acoustic
1 2
pressure spectrum becomes 3 dB below the peak level, at a specified point in the acoustic field
Note 1 to entry: Bandwidth is expressed in hertz (Hz).
3.7
beam area
A , A
b,6 b,20
area in a specified plane perpendicular to the beam axis consisting of all points at which the
pulse-pressure-squared integral is greater than a specified fraction of the maximum value of
the pulse-pressure-squared integral in that plane
Note 1 to entry: If the position of the plane is not specified, it is the plane passing through the point corresponding
to the maximum value of the pulse-pressure-squared integral in the whole acoustic field.
Note 2 to entry: In a number of cases, the term pulse-pressure-squared integral is replaced everywhere in the
above definition by any linearly related quantity, for example
a) in the case of a continuous wave signal the term pulse-pressure-squared integral is replaced by mean square
acoustic pressure as defined in IEC 61689,
b) in cases where signal synchronization with the scanframe is not available the term pulse-pressure-squared
integral may be replaced by temporal average intensity.
Note 3 to entry: Some specified fractions are 0,25 and 0,01 for the −6 dB and −20 dB beam areas, respectively.
Note 4 to entry: Beam area is expressed in units of metre squared (m ).
3.8
beam axis
straight line that passes through the beam centrepoints of two planes perpendicular to the line
which connects the point of maximal pulse-pressure-squared integral with the centre of the
external transducer aperture
SEE: Figure 1
Note 1 to entry: The location of the first plane is the location of the plane containing the maximum pulse-pressure-
squared integral or, alternatively, is one containing a single main lobe which is in the focal Fraunhofer zone. The
location of the second plane is as far as is practicable from the first plane and parallel to the first with the same two
orthogonal scan lines (x and y axes) used for the first plane.
Note 2 to entry: In a number of cases, the term pulse-pressure-squared integral is replaced in the above definition
by any linearly related quantity, for example
a) in the case of a continuous wave signal the term pulse-pressure-squared integral is replaced by mean square
acoustic pressure as defined in IEC 61689,
b) in cases where signal synchronization with the scanframe is not available the term pulse-pressure-squared
integral may be replaced by temporal average intensity.
3.9
beam centrepoint
position determined by the intersection of two lines in t
...