IEC 62127-1:2022
(Main)Ultrasonics - Hydrophones - Part 1: Measurement and characterization of medical ultrasonic fields
Ultrasonics - Hydrophones - Part 1: Measurement and characterization of medical ultrasonic fields
IEC 62127-1:2022 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.
IEC 62127-1:2022 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.
Ultrasons - Hydrophones - Partie 1: Mesurage et caractérisation des champs ultrasoniques médicaux
L’IEC 62127-1:2022 spécifie les méthodes d'utilisation des hydrophones étalonnés qui permettent de mesurer, dans des liquides, les champs acoustiques générés par des appareils médicaux à ultrasons, y compris les critères de largeur de bande et les exigences de plage de fréquences d’étalonnage en fonction du contenu spectral des champs à caractériser.
Le présent document:
- définit un groupe de paramètres acoustiques qui peuvent être mesurés sur une base physiquement sonore;
- définit un second groupe de paramètres qui peuvent être déduits, dans le cadre de certaines hypothèses, de ces mesurages et appelés paramètres d'intensité dérivés;
- définit un mode opératoire de mesure qui peut être utilisé pour déterminer les paramètres de pression acoustique;
- définit les conditions dans lesquelles les mesurages des paramètres acoustiques peuvent être réalisés à l'aide d'hydrophones étalonnés;
- définit les modes opératoires de correction, dans le cas de limitations provoquées par l'utilisation d'hydrophones à largeur de bande finie et de taille d'élément actif finie, ainsi que les modes opératoires d’estimation des incertitudes correspondantes.
L’IEC 62127-1:2022 annule et remplace la première édition parue en 2007 ainsi que l’Amendement 1:2013. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente.
a) La limite supérieure de fréquence de 40 MHz a été supprimée.
b) Les définitions de la sensibilité des hydrophones ont été modifiées pour considérer les sensibilités comme des grandeurs à valeurs complexes.
c) Les modes opératoires et les exigences concernant l’approximation à bande étroite et les mesurages à large bande ont été modifiés; des informations détaillées sur la déconvolution des formes d’onde ont été ajoutés.
d) Les modes opératoires de correction de la moyenne spatiale ont été modifiés.
e) L’Annexe D, l’Annexe E et la Bibliographie ont été mises à jour pour tenir compte des modifications apportées aux parties normatives.
General Information
Relations
Overview
IEC 62127-1:2022 - Ultrasonics: Hydrophones - Part 1: Measurement and characterization of medical ultrasonic fields defines standardized methods for using calibrated hydrophones to measure acoustic fields in liquids generated by medical ultrasonic equipment. The standard sets bandwidth and calibration frequency-range requirements based on the spectral content of fields, specifies which acoustic quantities can be measured directly and which are derived, and lays out procedures for correcting hydrophone limitations (finite bandwidth and active element size) and estimating measurement uncertainty.
Key topics and technical requirements
- Hydrophone calibration and sensitivity
- Requirements for using calibrated hydrophones, including recognition of complex-valued sensitivity (phase and magnitude).
- Bandwidth and calibration frequency-range criteria tied to field spectral content.
- Primary and derived acoustic parameters
- Defines a set of primary (measured) acoustic parameters and derived intensity parameters (e.g., pulse-pressure-squared integrals) that may be computed under stated assumptions.
- Beam characterization parameters such as peak-compressional/peak-rarefactional pressures, spatial-peak RMS pressure, and local distortion parameter.
- Measurement procedures and corrections
- Procedures for alignment, positioning, water-bath setup, data acquisition and analysis.
- Waveform deconvolution, modified narrow-band and broadband measurement approaches, and guidance on validation of deconvolution implementations.
- Spatial averaging correction methods and amended procedures for finite active element size.
- Instrumentation and environment
- Requirements for hydrophone types, amplifiers, cables, positioning systems, and water-bath preparation (including degassing considerations).
- Guidance on linearity, directional response, and effective hydrophone radius.
- Uncertainty and conformity
- Methods for estimating measurement uncertainty and compliance/conformity statements for reporting acoustic output.
Notable technical revisions versus earlier editions:
- Removal of the previous upper frequency limit (40 MHz).
- Hydrophone sensitivity treated as complex-valued.
- Expanded deconvolution and broadband/narrow-band procedures; updated spatial averaging correction and supporting annexes.
Applications and who uses this standard
IEC 62127-1:2022 is essential for:
- Acoustic metrology laboratories performing hydrophone-based measurements.
- Medical ultrasound manufacturers (diagnostic, therapeutic, surgical) validating transducer output.
- Regulatory bodies and test houses assessing device safety and compliance.
- Clinical engineers and research groups characterizing ultrasonic fields for device development and dosimetry studies.
Practical uses include characterizing diagnostic pulses, therapeutic fields, lithotripter outputs, and multi-mode fields where precise pressure and intensity metrics and uncertainty quantification are required.
Related standards
Refer to other parts of the IEC 62127 hydrophone series and relevant IEC medical ultrasound safety and performance standards for broader conformity and device-specific test methods.
Standards Content (Sample)
IEC 62127-1 ®
Edition 2.0 2022-03
REDLINE VERSION
INTERNATIONAL
STANDARD
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inside
Ultrasonics – Hydrophones –
Part 1: Measurement and characterization of medical ultrasonic fields up to
40 MHz
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IEC 62127-1 ®
Edition 2.0 2022-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Ultrasonics – Hydrophones –
Part 1: Measurement and characterization of medical ultrasonic fields up to
40 MHz
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.140.50 ISBN 978-2-8322-5195-9
– 2 – IEC 62127-1:2022 RLV © IEC 2022
CONTENTS
FOREWORD . 6
INTRODUCTION . 2
1 Scope and object . 9
2 Normative references . 9
3 Terms and definitions . 10
4 Symbols . 16
5 Measurement requirements . 38
5.1 Requirements for hydrophones and amplifiers. 38
5.1.1 Introduction Preface . 38
5.1.2 General . 38
5.1.3 Sensitivity of a hydrophone . 39
5.1.4 Directional response of a hydrophone . 39
5.1.5 Effective hydrophone radius size . 39
5.1.6 Choice of the size of a hydrophone active element . 40
5.1.7 Bandwidth. 41
5.1.8 Linearity . 42
5.1.9 Hydrophone signal amplifier . 44
5.1.10 Hydrophone cable length and amplifiers . 45
5.2 Requirements for positioning and water baths . 45
5.2.1 General . 45
5.2.2 Positioning systems . 45
5.2.3 Water bath . 46
5.3 Requirements for data acquisition and analysis systems . 47
5.4 Recommendations for ultrasonic equipment being characterized. 48
6 Measurement procedure . 48
6.1 General . 48
6.2 Preparation and alignment . 48
6.2.1 Preparation . 48
6.2.2 Aligning an ultrasonic transducer and a hydrophone . 48
6.3 Measurement . 49
6.4 Analysis . 49
6.4.1 Corrections for restricted bandwidth and spatial resolution . 49
6.4.2 Uncertainties . 49
7 Beam characterization . 49
7.1 General . 49
7.2 Primary pressure parameters . 51
7.2.1 General . 51
7.2.2 Peak-compressional acoustic pressure and peak-rarefactional acoustic
pressure . 52
7.2.3 Spatial-peak RMS acoustic pressure . 52
7.2.4 Local distortion parameter . 53
7.3 Intensity parameters using instantaneous derived from acoustic pressure . 53
7.3.1 General . 53
7.3.2 Intensity parameters using pulse-pressure-squared integral . 54
8 Requirements for specific ultrasonic fields . 57
8.1 General . 57
8.2 Diagnostic fields . 57
8.2.1 Simplified procedures and guidelines . 57
8.2.2 Pulsed wave diagnostic equipment . 58
8.2.3 Continuous wave diagnostic equipment . 59
8.2.4 Diagnostic equipment with low acoustic output . 59
8.3 Therapy fields . 59
8.3.1 Physiotherapy equipment. 59
8.3.2 Hyperthermia .
8.3.2 High intensity therapeutic ultrasonic fields . 60
8.3.3 Non-focused and weakly focused pressure pulses . 61
8.4 Surgical fields . 61
8.4.1 Lithotripters and pressure pulse sources for other therapeutic purposes . 61
8.4.2 Low frequency surgical applications . 61
8.5 Fields from other medical applications . 61
9 Compliance Conformity statement . 61
9.1 General . 61
9.2 Maximum probable values . 62
9.3 Sampling. 62
Annex A (informative) General rationale. 63
Annex B (informative) Hydrophones and positioning . 65
B.1 General . 65
B.2 Electrical loading considerations . 65
B.3 Hydrophone signal amplifier . 65
B.4 Hydrophone cable length and amplifiers . 65
B.5 Transducer positioning . 66
B.6 Alignment of hydrophones . 67
B.7 Water bath lining material . 67
B.8 Recommendations for ultrasonic equipment being characterized. 68
B.9 Types of hydrophones . 68
B.9.1 Ceramic needle hydrophones . 68
B.9.2 PVDF needle hydrophones . 68
B.9.3 PVDF membrane hydrophones . 69
B.9.4 Fibre-optic and optic hydrophones . 69
B.9.5 Relative performance of different types . 70
B.10 Typical specification data for hydrophones . 70
Annex C (informative) Acoustic pressure and intensity . 72
Annex D (informative) Voltage to pressure conversion . 74
D.1 General . 74
D.2 Hydrophone deconvolution procedure . 75
D.3 Converting the data between double-sided and single-sided spectra . 77
D.4 Use of hydrophone calibration data . 79
D.4.1 Calibration data interpolation . 79
D.4.2 Calibration data extrapolation . 79
D.4.3 Regularization filtering . 80
D.5 Implication of the hydrophone deconvolution process on measurement
duration . 79
D.6 Validation of deconvolution implementation . 82
– 4 – IEC 62127-1:2022 RLV © IEC 2022
Annex E (informative) Correction for spatial averaging . 83
E.1 Linear and quasilinear fields . 83
E.2 Linear fields, quasilinear fields, and broadband nonlinearly distorted
waveforms . 85
Annex F (informative) Acoustic output parameters for multi-mode medical ultrasonic
fields in the absence of scan-frame synchronization . 88
F.1 General . 88
F.2 Current philosophy . 88
F.3 Need for change an alternative approach . 89
F.4 Proposed changes approach . 89
F.4.1 Alternative philosophy . 89
F.4.2 Alternative parameters . 90
F.5 Measurement methods . 91
F.5.1 General . 91
F.5.2 Peak pressures . 92
F.5.3 Temporal-average intensity . 92
F.5.4 Frequency . 92
F.5.5 Power . 93
F.6 Discussion . 93
F.6.1 Relationship to existing standards . 93
F.6.2 Advantages . 93
F.6.3 Disadvantages . 93
Annex G (informative) Propagation medium and degassing. 95
Annex H (informative) Specific ultrasonic fields . 96
H.1 Diagnostic fields . 96
H.1.1 Useful relationships between acoustical parameters . 96
H.1.2 Pulsed wave diagnostic equipment . 97
H.1.3 Continuous wave diagnostic equipment . 98
H.2 Therapy fields . 98
H.2.1 Physiotherapy equipment. 98
H.2.2 Hyperthermia .
H.2.2 High intensity therapeutic ultrasonic equipment . 98
H.2.3 Non-focused and weakly focused pressure pulses . 99
H.3 Surgical fields . 99
H.3.1 Lithotripters . 99
H.3.2 Low frequency surgical applications . 99
Annex I (informative) Assessment of uncertainty in the acoustic quantities obtained by
hydrophone measurements . 100
I.1 General . 100
I.2 Overall (expanded) uncertainty . 100
I.3 Common sources of uncertainty . 100
Annex J (informative) Transducer and hydrophone positioning systems . 102
Annex K (informative) Beamwidth midpoint method . 103
Bibliography . 36
Figure 1 – Schematic diagram of the different planes and lines in an ultrasonic field . 14
Figure 2 – Several apertures and planes for a transducer of unknown geometry . 28
Figure 3 – Parameters for describing an example of a focusing transducer of known
geometry . 33
Figure 4 – Schematic diagram of the method of determining pulse duration . 51
Figure D.1 – A flow diagram of the hydrophone deconvolution process . 77
Figure D.2 – Example of waveform deconvolution . 81
Figure J.1 – Schematic diagram of the ultrasonic transducer and hydrophone degrees
of freedom . 102
Table 1 – Acoustic parameters appropriate to various types of medical ultrasonic
equipment . 50
Table B.1 – Typical specification data for hydrophones, in this case given at
1 MHz [69] . 71
Table C.1 – Properties of distilled or de-ionized water as a function of temperature [71] . 73
Table D.1 – Method of conversion from a double- to a single-sided spectrum . 78
Table D.2 – Method of conversion from a single- to a double-sided spectrum . 78
Table F.1 – Main basic parameters defined in this document or in IEC 61161 . 89
Table F.2 – List of parameters that are to be used or are to be deleted . 91
Table K.1 – Decibel beamwidth levels for determining midpoints . 103
– 6 – IEC 62127-1:2022 RLV © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ULTRASONICS – HYDROPHONES –
Part 1: Measurement and characterization of medical ultrasonic
fields up to 40 MHz
FOREWORD
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This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 62127-1:2007+AMD1:2013 CSV. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in strikethrough
red text.
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.
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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.
– 8 – IEC 62127-1:2022 RLV © 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.
ULTRASONICS – HYDROPHONES –
Part 1: Measurement and characterization of medical ultrasonic
fields up to 40 MHz
1 Scope and object
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 operating
in the frequency range up to 40 MHz 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 may can be used for the determination of acoustic
pressure parameters;
– defines the conditions under which the measurements of acoustic parameters can be made
in the frequency range up to 40 MHz 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 may can be convenient to use decimal multiples or submultiples. For example, beam area
2 2 2
may is likely to be specified in cm and intensities in W/cm or mW/cm .
NOTE 2 The hydrophone as defined may 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 60050-801:1994, International Electrotechnical Vocabulary – Chapter 801: Acoustics and
electroacoustics
IEC 60565, Underwater acoustics – Hydrophones – Calibration in the frequency range 0,01 Hz
to 1 MHz
IEC 60565-1, Underwater acoustics – Hydrophones – Calibration of hydrophones – Part 1:
Procedures for free-field calibration of hydrophones
IEC/TR 60854:1986, Methods of measuring the performance of ultrasonic pulse-echo
diagnostic equipment
IEC 61689, Ultrasonics – Physiotherapy systems – Performance requirements Field
specifications and methods of measurement in the frequency range 0,5 MHz to 5 MHz
– 10 – IEC 62127-1:2022 RLV © IEC 2022
IEC 61828, Ultrasonics – Focusing transducers – Definitions and measurement methods for the
transmitted fields
IEC 61846, Ultrasonics – Pressure pulse lithotripters – Characteristics of fields
IEC 61847, Ultrasonics – Surgical systems – Measurement and declaration of the basic output
characteristics
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 16269-6:2005, 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)
NOTE The following standards rely on the proper use of this document.
IEC 61157, Standard means for the reporting of the acoustic output of medical diagnostic ultrasonic equipment
IEC 62359, Ultrasonics – Field characterization – Test methods for the determination of thermal and mechanical
indices related to medical diagnostic ultrasonic fields
IEC 61847, Ultrasonics – Surgical systems – Measurement and declaration of the basic output characteristics.
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. It also includes definitions related to subjects in this document to be
used in particular medical ultrasound device standards.
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 should 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 should are expected to show evidence of phase change.
Note 2 to entry: The measurement should be 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.
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 magnitude level of the acoustic pressure spectrum is 3 dB below the peak
magnitude 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 magnitude level is 3 dB below the peak magnitude 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
with Pf() =
f = (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;
– 12 – IEC 62127-1:2022 RLV © IEC 2022
P()f
L (f) is the pressure level spectrum given from Lf( ) = 20log dB with P = 1 Pa.
P P 10 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
arithmetic-mean acoustic-working frequency of the pulse with the largest peak negative
acoustic pressure measured at the point of maximum peak negative acoustic pressure
NOTE Peak pulse acoustic frequency is expressed in hertz (Hz).
3.3.5
time temporal-average acoustic frequency
f
t
arithmetic-mean acoustic-working frequency of the time averaged acoustic pressure
spectrum of the acoustic signals measured at the point of maximum temporal-average
intensity
NOTE Time average acoustic frequency is expressed in hertz (Hz).
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 61828:20012020, 3.7]
Z Y
X
Y Z
IEC 1638/07
Key
X azimuth axis
Y elevation axis
Z beam axis
1 external transducer aperture plane
2 source aperture plane
3 aperture plane
4 beam area plane
5 beamwidth lines
6 azimuth plane, scan plane
7 elevation plane
8 longitudinal plane
9 principle longitudinal plane
– 14 – IEC 62127-1:2022 RLV © IEC 2022
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
for a scanning ultrasonic transducer: this is the scan plane; for a non-scanning ultrasonic
transducer: this is the principal longitudinal plane
plane containing the beam axis and the line of the minimum full width half maximum
beamwidth
SEE: Figure 1
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 61828:20012020, 3.8]
3.6
bandwidth
BW
difference in the most widely separated frequencies f and f at which the magnitude level of
1 2
the acoustic pressure spectrum becomes 3 dB below the peak magnitude 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 ).
NOTE 5 Definition is modified compared to that used in IEC 61828:2001.
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.
NOTE 4 Definition is modified compared to that used in IEC 61828:2001.
3.9
beam centrepoint
position determined by the intersection of two lines in the same beam area plane xy passing
through the beamwidth midpoints of two orthogonal planes, xz and yz, perpendicular to their
respective beamwidth lines
[SOURCE: IEC 61828:20012020, 3.15, modified – In the definition, "in the same beam area
plane xy" and ", perpendicular to their respective beamwidth lines" have been added.]
– 16 – IEC 62127-1:2022 RLV © IEC 2022
3.10
beamwidth midpoint
linear average of the location of the centres of beamwidths in a plane
Note 1 to entry: The beamwidth midpoint method is described in Annex K.
Note 2 to entry: The average is taken over as many beamwidth levels given in Table K.1 as signal level permits.
[SOURCE: IEC 61828:20012020, 3.22, modified – Note 1 to entry has been replaced by new
Notes to entry.]
3.11
beamwidth
w , w , w
6 12 20
greatest distance between two points on a specified axis perpendicular to the beam axis where
the pulse-pressure-squared integral falls below its maximum on the specified axis by a
specified amount
Note 1 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 can be replaced by temporal average intensity.
Note 2 to entry: Commonly used beamwidths are specified at −6 dB, −12 dB and −2
...
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
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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
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
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
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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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
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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
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other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
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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.
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.
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.
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
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 the same beam area plane xy passing
through the beamwidth midpoints of two orthogonal planes, xz and yz, perpendicular to their
respective beamwidth lines
[SOURCE: IEC 61828:2020, 3.15, modified – In the definition, "in the same beam area plane xy"
and ", perpendicular to their respective beamwidth lines" have been added.]
– 14 – IEC 62127-1:2022 © IEC 2022
3.10
beamwidth midpoint
linear average of the location of the centres of beamwidths in a plane
Note 1 to entry: The beamwidth midpoint method is described in Annex K.
Note 2 to entry: The average is taken over as many beamwidth levels given in Table K.1 as signal level permits.
[SOURCE: IEC 61828:2020, 3.22, modified – Note 1 to entry has been replaced by new Notes
to entry.]
3.11
beamwidth
w , w , w
6 12 20
greatest distance between two points on a specified axis perpendicular to the beam axis where
the pulse-pressure-squared integral falls below its maximum on the specified axis by a
specified amount
Note 1 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 can be replaced by temporal average intensity.
Note 2 to entry: Commonly used beamwidths are specified at −6 dB, −12 dB and −20 dB levels below the
maximum. The decibel calculation implies taking 10 times the logarithm of the ratios of the integrals.
Note 3 to entry: Beamwidth is expressed in metres (m).
3.12
broadband transducer
transducer that generates an acoustic pulse of which the bandwidth is greater than the
acoustic-working frequency
3.13
central scan line
ultrasonic scan line closest to the symmetry axis of the
scan plane
3.14
derived instantaneous intensity
quotient of squared instantaneous acoustic pressure and characteristic acoustic impedance
of the me
...
Frequently Asked Questions
IEC 62127-1:2022 is a standard published by the International Electrotechnical Commission (IEC). Its full title is "Ultrasonics - Hydrophones - Part 1: Measurement and characterization of medical ultrasonic fields". This standard covers: IEC 62127-1:2022 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. IEC 62127-1:2022 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 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. IEC 62127-1:2022 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 is classified under the following ICS (International Classification for Standards) categories: 17.140.50 - Electroacoustics. The ICS classification helps identify the subject area and facilitates finding related standards.
IEC 62127-1:2022 has the following relationships with other standards: It is inter standard links to IEC 62127-1:2007, IEC 62127-1:2007/AMD1:2013, IEC 62127-1:2007/COR1:2008. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase IEC 62127-1:2022 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of IEC standards.
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