SIST EN 55017:2011

Methods of measurement of the suppression characteristics of passive EMC filtering devices (CISPR 17:2011)

CISPR 17:2011 specifies methods to measure the radio interference suppression characteristics of passive EMC filtering devices used in power and signal lines, and in other circuits. The defined methods may also be applied to combinations of over-voltage protection devices and EMC filtering devices. The measurement method covers the frequency range from 9 kHz to several GHz depending on the device and test circuit. The standard describes procedures for laboratory tests (type tests) as well as factory tests. The suppression characteristics of EMC filters and components used for the suppression of EM disturbances, are a function of numerous variables such as impedance of the circuits to which they connect, operating voltage and current, and ambient temperature. This standard specifies uniform test methods that will enable comparison of filtering and suppression characteristics determined by test laboratories or specified by manufacturers. Measurement procedures are provided for unbiased and bias conditions. Measurements under bias conditions are performed to determine potential non-linear behaviour of the EMC filtering devices such as saturation effects in inductors with magnetic cores. This testing serves to show the usability in a specific application (such as frequency converters that produce high amplitudes of common mode pulse current and thus may drive inductors into saturation). Measurement under bias conditions may be omitted if the non-linear behaviour can be determined by other methods (e.g. separate saturation measurement of the inductors used). The first edition of CISPR 17 (1981) prescribed the measurement methods of insertion loss mainly for power-line filters. Today, however, many types of sophisticated EMC filters and suppression components can be found in various electronic devices. Those filters need to be characterized using standardized measurement methods. New methods for measurement of impedance and S-parameters for such EMI devices are included in this second edition.

Verfahren zur Messung der Entstöreigenschaften von passiven EMV-Filtern (CISPR 17:2011)

Méthodes de mesure des caractéristiques d'antiparasitage des dispositifs de filtrage CEM passifs (CISPR 17:2011)

La CISPR 17:2011 spécifie les méthodes de mesure des caractéristiques d'antiparasitage des perturbations radioélectriques des dispositifs de filtrage CEM passifs utilisés dans les lignes électriques et de transmission de signaux et dans d'autres circuits. Les méthodes définies peuvent également s'appliquer aux combinaisons de dispositifs de protection contre les surtensions et les dispositifs de filtrage CEM. La méthode de mesure décrite couvre la gamme de fréquences comprise entre 9 kHz et plusieurs GHz, en fonction du dispositif et du circuit d'essai. La norme décrit des méthodes applicables aux essais en laboratoire (essais de type) et aux essais en usine. Des méthodes d'essai avec et sans conditions de polarisation sont définies. Les caractéristiques d'antiparasitage des filtres et éléments CEM utilisés pour la réduction des perturbations CEM sont fonction de nombreuses variables telles que l'impédance des circuits auxquels elles sont associées, la tension et le courant d'utilisation et la température ambiante. La présente norme spécifie des méthodes d'essai uniformes qui permettent de comparer les caractéristiques de filtrage et d'antiparasitage déterminées par les laboratoires d'essai ou précisées par les constructeurs. Des méthodes de mesure sont fournies pour des conditions avec et sans polarisation. Les mesures effectuées dans des conditions de polarisation permettent de déterminer le comportement non linéaire potentiel des dispositifs de filtrage CEM, comme les effets de saturation exercés sur les inductances à noyaux magnétiques. Ces essais permettent de montrer la facilité d'emploi dans une application spécifique (telle que dans les cas de convertisseurs de fréquence qui produisent de grandes amplitudes de courant de choc de mode commun, et peuvent ainsi entraîner la saturation des inductances). Il n'est pas nécessaire d'effectuer des mesures dans des conditions de polarisation si le comportement non linéaire peut être déterminé par d'autres méthodes (par exemple, mesure séparée de la saturation des inductances utilisées). La première édition du document CISPR 17 (1981) spécifiait les méthodes de mesure de l'affaiblissement d'insertion principalement pour les filtres réseau. Aujourd'hui, divers dispositifs électroniques comportent toutefois de nombreux types de filtres et d'éléments d'antiparasitage CEM complexes. Ces filtres doivent être caractérisés au moyen de méthodes de mesure normalisées. Cette seconde édition comporte les nouvelles méthodes de mesure de l'impédance et des paramètres S pour ce type de dispositifs EMI.

Postopki za merjenje dušenja pasivnih EMC filtrskih naprav (CISPR 17:2011)

Ta mednarodni standard določa metode za merjenje karakteristik dušenja radijskih motenj pasivnih filtrov EMC, ki se uporabljajo pri napajalnih in signalnih vodih ter drugih tokokrogih. Opredeljene metode lahko veljajo za kombinacije zaščitnih naprav pred presežno napetostjo in filtre EMC. Merilna metoda zajema frekvenčni razpon med 9 kHz in več GHz, odvisno od naprave in preskušanega tokokroga. OPOMBA: Merilne metode v tem standardu se lahko uporabljajo do 40 GHz. Standard opisuje postopke za laboratorijske preskuse (tipske preskuse) in tovarniške preskuse. Opredeljene so preskusne metode s pogoji vplivanja in brez njih. Podani so merilni postopki za pogoje brez vplivanja in z njim. Meritve v pogojih vplivanja se izvajajo za ugotavljanje potencialnega nelinearnega obnašanja filtrov EMC, kot so učinki nasičenosti v induktorjih z magnetnimi jedri. To preskušanje je namenjeno prikazu uporabnosti pri določeni aplikaciji (kot so frekvenčni pretvorniki, ki proizvajajo visoke amplitude pulznega toka v splošnem načinu, kar lahko povzroči nasičenost pretvornikov). Merjenje v okoliščinah vplivanja se lahko izpusti, če se nelinearno obnašanje lahko določi z drugimi metodami (npr. ločeno merjenje nasičenosti uporabljenih induktorjev).

General Information

• Status: Published
• Public Enquiry End Date: 29-Apr-2010
• Publication Date: 17-Oct-2011
• ICS: 33.100.99 - Other aspects related to EMC
• Technical Committee: EMC - Electromagnetic compatibility
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 10-Oct-2011
• Due Date: 15-Dec-2011
• Completion Date: 18-Oct-2011
• Directive: 2004/108/EC - Directive 2004/108/EC of the European Parliament and of the Council of 15 December 2004 on the approximation of the laws of the Member States relating to electromagnetic compatibility and repealing Directive 89/336/EEC
• Directive: 2004/108/EU - DIRECTIVE 2004/108/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 15 December 2004 on the approximation of the laws of the Member States relating to electromagnetic compatibility and repealing Directive 89/336/EEC
• Directive: 2014/30/EU - Directive 2014/30/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to electromagnetic compatibility (recast)
• Ref Project: EN 55017:2011 - Methods of measurement of the suppression characteristics of passive EMC filtering devices

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2011
Postopki za merjenje dušenja pasivnih EMC filtrskih naprav (CISPR 17:2011)
0HWKRGVRIPHDVXUHPHQWRIWKHVXSSUHVVLRQFKDUDFWHULVWLFVRISDVVLYH(0&ILOWHULQJ
GHYLFHV
&,635
Verfahren zur Messung der Entstöreigenschaften von passiven EMV-Filtern (CISPR
17:2011)
Méthodes de mesure des caractéristiques d'antiparasitage des dispositifs de filtrage
CEM passifs (CISPR 17:2011)
Ta slovenski standard je istoveten z: EN 55017:2011
ICS:
33.100.99 Drugi vidiki v zvezi z EMC Other aspects related to
EMC
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 55017
NORME EUROPÉENNE
September 2011
EUROPÄISCHE NORM
ICS 33.100.01
English version
Methods of measurement of the suppression characteristics of passive
EMC filtering devices
(CISPR 17:2011)
Méthodes de mesure des caractéristiques Verfahren zur Messung der
d'antiparasitage des dispositifs de filtrage Entstöreigenschaften von passiven EMV-
CEM passifs Filtern
(CISPR 17:2011) (CISPR 17:2011)

This European Standard was approved by CENELEC on 2011-07-15. 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, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 55017:2011 E
Foreword
The text of document CISPR/A/941/FDIS, future edition 2 of CISPR 17, prepared by CISPR SC A,
"Radio-interference measurements and statistical methods", was submitted to the IEC-CENELEC parallel
vote and was approved by CENELEC as EN 55017 on 2011-07-15.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2012-04-15
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2014-07-15
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard CISPR 17:2011 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
CISPR 12:2007 NOTE  Harmonized as EN 55012:2007 (not modified).
__________
- 3 - EN 55017:2011
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60050-161 - International Electrotechnical Vocabulary - -
(IEV) -
Chapter 161: Electromagnetic compatibility

CISPR 17 ®
Edition 2.0 2011-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE
COMITÉ INTERNATIONAL SPÉCIAL DES PERTURBATIONS RADIOÉLECTRIQUES

Methods of measurement of the suppression characteristics of passive EMC
filtering devices
Méthodes de mesure des caractéristiques d’antiparasitage des dispositifs de
filtrage CEM passifs
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XB
ICS 33.100.01 ISBN 978-2-88912-526-5

– 2 – CISPR 17  IEC:2011
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms, definitions and abbreviations . 9
3.1 Terms and definitions . 9
3.2 Abbreviations . 12
4 Classification of EMC filtering devices . 12
4.1 Insertion loss . 14
4.1.1 Insertion loss calculation . 14
4.1.2 Asymmetrical (common) mode . 14
4.1.3 Symmetrical (differential) mode . 14
4.1.4 Unsymmetrical mode . 14
4.2 Impedance . 14
4.3 S-parameters . 15
4.3.1 General . 15
4.3.2 Two-port S-parameters . 15
4.3.3 Four-port S-parameters . 16
5 Insertion loss measurement . 17
5.1 General . 17
5.2 Measurement set-up . 18
5.2.1 General . 18
5.2.2 Test equipment . 18
5.2.3 Asymmetrical (common mode) test circuit . 19
5.2.4 Symmetrical (differential mode) test circuit . 19
5.2.5 Unsymmetrical test circuit . 20
5.3 Measurement methods (procedure) . 21
5.3.1 General . 21
5.3.2 Measurement without bias . 22
5.3.3 Measurement with bias . 22
5.4 Calibration and verification . 23
5.4.1 General . 23
5.4.2 Validation of test set-up without bias . 23
5.4.3 Validation of test set-up with bias . 24
5.5 Uncertainty . 26
6 Impedance measurement . 26
6.1 General . 26
6.2 Direct method . 26
6.2.1 Measurement set-up and procedure . 26
6.2.2 Calibrations of the test set-up . 27
6.2.3 Measurement uncertainty . 27
6.3 Indirect method . 27
6.3.1 Measurement set-up and procedure . 27
6.3.2 Calibration of the test set-up . 29
6.3.3 Measurement uncertainty . 29
7 S-parameter measurement . 30

CISPR 17  IEC:2011 – 3 –
7.1 Measurement set-up and procedure . 30
7.1.1 General . 30
7.1.2 Test fixture . 31
7.2 Calibration of test set-up . 36
7.3 Measurement uncertainties . 36
8 Presentation of results . 36
8.1 General . 36
8.2 Insertion loss . 37
8.3 Impedance . 37
8.4 S-parameters . 37
Annex A (normative) Uncertainty estimation for the measurement of the suppression
characteristics of EMC filtering devices . 38
Annex B (informative) Examples of test boxes for insertion loss measurement . 43
Annex C (informative) Insertion loss test methods with non-50 Ω systems . 47
Annex D (informative) Realization of the buffer-network for insertion loss
measurement . 49
Annex E (informative) Insertion loss measurement – General discussion . 51
Annex F (informative) Set-up for impedance measurement . 54
Annex G (informative) S-parameter measurement of common-mode choke coils . 59
Annex H (informative) Measurement set-up for S-parameters of a DUT without wire
leads . 64
Bibliography . 66

Figure 1 – Measurement arrangement for S-parameters of a two-terminal device . 15
Figure 2 – Measurement arrangement for S-parameters of a three-terminal device . 15
Figure 3 – Measurement arrangement for four-port S-parameters . 16
Figure 4 – Test circuit for insertion loss measurement (example: 4-line-filter) . 18
Figure 5 – Test circuit for asymmetrical insertion loss measurement (example:
4-line-filter) . 19
Figure 6 – Test circuit for symmetrical insertion loss measurement (example: 4-line-
filter) . 20
Figure 7 – Test circuit for unsymmetrical insertion loss measurement (example:
4-line filter) . 21
Figure 8 – Test circuit for insertion loss measurement without bias . 22
Figure 9 – Test circuit for insertion loss measurement with bias . 22
Figure 10 – Test circuit for verification of measurement circuit without bias . 23
Figure 11 – Test circuit for verification of measurement circuit with bias . 25
Figure 12 – One-port measurement of a two-terminal device . 28
Figure 13 – S-parameter measurements for evaluating the impedance of a device in a
series connection . 28
Figure 14 – S-parameter measurements for evaluating the impedance of a device in a
shunt connection. 28
Figure 15 – Two-port S-parameter measurement set-up . 30
Figure 16 – An alternative measurement system specifically for the insertion loss of a
DUT (using a combination of tracking generator and measuring receiver) . 31
Figure 17 – Symbolic expressions . 32
Figure 18 – Test fixture for a two-terminal device (series connection) . 32

– 4 – CISPR 17  IEC:2011
Figure 19 – Test fixture for a two-terminal device (shunt connection) . 33
Figure 20 – Test fixture for a three-terminal filter . 33
Figure 21 – Test fixture for a two-terminal device with leads . 34
Figure 22 – Test fixture for a three-terminal filter with leads . 35
Figure 23 – Test fixture for a core device . 35
Figure 24 – Example of the standards for TRL calibration . 36
Figure B.1 – Design of typical test box for general-purpose filters . 43
Figure B.2 – 3D view of typical test box for general purpose filters . 44
Figure B.3 – Design of typical test box for feedthrough components . 45
Figure B.4 – 3D view of typical test box for feedthrough components . 45
Figure C.1 – Test circuit . 47
Figure D.1 – Example of connecting buffer-networks for test with bias . 49
Figure E.1 – Test circuit for insertion loss measurement, reference measurement
(filter replaced by a short circuit) . 51
Figure E.2 – Test circuit for insertion loss measurement, measurement of filter under test . 52
Figure F.1 – Measurement set-up for a leaded device (DUT) . 54
Figure F.2 – Four-terminal test fixture for a leaded device (DUT) . 55
Figure F.3 – Measurement set-up for an SMD . 55
Figure F.4 – Clamp-type test fixture . 56
Figure F.5 – Coaxial test fixture for an SMD . 56
Figure F.6 – Press-type test fixture for an SMD. 57
Figure F.7 – Connection for CMCC measurement . 57
Figure F.8 – Test fixture and measurement set-up for an SMD common-mode choke coil . 58
Figure G.1 – Common-mode choke coil . 59
Figure G.2 – Set-up for measurements of common-mode characteristics . 59
Figure G.3 – Test fixture for an SMD. 60
Figure G.4 – Test fixture for a leaded device . 60
Figure G.5 – Set-up for measurements of differential-mode characteristics . 61
Figure G.6 – Test fixture for an SMD. 61
Figure G.7 – Test fixture for a leaded device . 61
Figure G.8 – Set-up for measurement of four-port S-parameters . 62
Figure G.9 – Test fixture for the four-port S-parameters of an SMD . 62
Figure G.10 – Test fixture for the four-port S-parameters of a leaded device . 63
Figure H.1 – S-parameters measurement of a DUT without leads . 64
Figure H.2 – Procedure for TRL calibration . 65

Table 1 – Examples of EMC filtering devices . 13
Table 2 – Conditions and target values for validation of test set-up without bias . 24
Table 3 – Conditions and target values for validation of test set-up with bias . 25
Table A.1 – Measurement uncertainty of insertion loss (example) . 40
Table A.2 – Measurement uncertainty of impedance (example) . 41
Table A.3 – Measurement uncertainties of |S | and |S | (example) . 41
21 12
Table A.4 – Measurement uncertainties of |S | and |S | (example) . 41
11 22
CISPR 17  IEC:2011 – 5 –
Table D.1 – Specifications of the elements of buffer-networks . 50

– 6 – CISPR 17  IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METHODS OF MEASUREMENT OF THE SUPPRESSION
CHARACTERISTICS OF PASSIVE EMC FILTERING DEVICES

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
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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
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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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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.
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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.
International Standard CISPR 17 has been prepared by CISPR subcommittee A: Radio
interference measurements and statistical methods.
This second edition cancels and replaces the first edition published in 1981. It is a technical
revision.
This edition includes the following significant technical change with respect to the previous
edition: new measurement methods are added to characterize the more technologically
sophisticated EMC filtering devices currently available.
The text of this standard is based on the following documents:
FDIS Report on voting
CISPR/A/941/FDIS CISPR/A/951/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

CISPR 17  IEC:2011 – 7 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication 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 publication using a colour printer.

– 8 – CISPR 17  IEC:2011
INTRODUCTION
The suppression characteristics of EMC filters and components used for the suppression of
EM disturbances, referred to in this standard as EMC filtering devices, are a function of
numerous variables such as impedance of the circuits to which they connect, operating
voltage and current, and ambient temperature. This standard specifies uniform test methods
that will enable comparison of filtering and suppression characteristics determined by test
laboratories or specified by manufacturers.
The first edition of CISPR 17 (1981) prescribed the measurement methods of insertion loss
mainly for power-line filters. Today, however, many types of sophisticated EMC filters and
suppression components can be found in various electronic devices. Those filters need to be
characterized using standardized measurement methods. New methods for measurement of
impedance and S-parameters for such EMI devices are included in this second edition.
In addition, the following insertion loss measurement methods from the first edition have been
deleted because they are no longer in use in the industry:
• measurement method with a bias voltage for insertion loss measurement,
• in situ method, and
• worst-case methods.
CISPR 17  IEC:2011 – 9 –
METHODS OF MEASUREMENT OF THE SUPPRESSION
CHARACTERISTICS OF PASSIVE EMC FILTERING DEVICES

1 Scope
This International standard specifies methods to measure the radio interference suppression
characteristics of passive EMC filtering devices used in power and signal lines, and in other
circuits.
The defined methods may also be applied to combinations of over-voltage protection devices
and EMC filtering devices.
The measurement method covers the frequency range from 9 kHz to several GHz depending
on the device and test circuit.
NOTE Measurement methods in this standard may be applied up to 40 GHz.
The standard describes procedures for laboratory tests (type tests) as well as factory tests.
Test methods with and without bias conditions are defined.
Measurement procedures are provided for unbiased and bias conditions. Measurements
under bias conditions are performed to determine potential non-linear behaviour of the EMC
filtering devices such as saturation effects in inductors with magnetic cores. This testing
serves to show the usability in a specific application (such as frequency converters that
produce high amplitudes of common mode pulse current and thus may drive inductors into
saturation). Measurement under bias conditions may be omitted if the non-linear behaviour
can be determined by other methods (e.g. separate saturation measurement of the inductors
used).
2 Normative references
The following referenced documents are indispensable for the application 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 60050-161, International Electrotechnical Vocabulary (IEV) – Chapter 161:
Electromagnetic compatibility
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions, as well as those given
in IEC 60050-161, apply.
3.1.1
bias current
d.c. or a.c. mains (power) frequency current flowing through the current conductor(s) of the
EMC filtering device under test

– 10 – CISPR 17  IEC:2011
3.1.2
bias voltage
d.c. or a.c. mains (power) frequency voltage applied between specified parts of the EMC
filtering device under test
3.1.3
device under test
EMC filtering device subjected to measurement, calibration and test according to this
standard
3.1.4
EMC filtering device
a generic term within this standard to describe any kind of suppression circuit, whether a
single component or a complex circuit
3.1.5
filter
composition of single components such as inductors and capacitors that can suppress
electromagnetic disturbance
3.1.6
impedance
Z
ratio of an a.c. electric current I to an a.c. voltage V (at frequency f ), which may be
represented by a complex number expressed as Z = V/I, indicating the total opposition to the
passage of a.c. current; used as a parameter to represent the characteristics of two-terminal
devices such as inductors, capacitors, and resistors, as well as those of four-terminal devices
such as common-mode choke coils (CMCC)
NOTE Consists of ohmic resistance R and reactance X, usually represented in complex notation as Z = R + jX;
alternatively represented in the polar coordinates as |Z| exp(jθ) (absolute value |Z| and phase angle θ); may imply
the performance of an EMC filtering device; Z is expressed in Ω.
3.1.7
insertion loss
for a filter connected into a given transmission system, the ratio of voltages appearing across
the line immediately beyond the point of insertion, before and after insertion of the EMC
filtering device under test
NOTE Insertion loss is expressed in dB.
3.1.8
impedances of the test circuit
impedance across the terminals of the test circuit without the filter connected
NOTE For insertion loss measurement shown in Figure 4, impedances are designated Z , Z , Z and Z
0 11 12 2
referenced to 50 Ω; in special cases the impedances may be changed to other values that reflect the environmental
conditions of certain applications.
3.1.9
receiver
selective or non-selective instrument, such as a broadband voltmeter, a tunable voltmeter, a
spectrum analyzer or the receiving part of a network analyzer
NOTE See 5.2.2 for details.
3.1.10
reference impedance
impedance of a line or port at the point where the insertion loss or S-parameters are
measured or evaluated, specified when results are reported

CISPR 17  IEC:2011 – 11 –
NOTE The reference impedance is usually 50 Ω.
3.1.11
reference potential
reference for voltage measurement to which the ground connections of the test equipment
and the filter are connected, normally provided by a metallic plane of sufficient size
3.1.12
single component
basic component used for EMC purposes such as capacitors or inductors
3.1.13
S-parameter
scattering parameter
S
ij
an element of the S-matrix expressing the transmission and reflection coefficients of a device
NOTE 1 As most commonly used, each S-parameter relates the complex electric field strength (or voltage) of a
reflected or transmitted wave to that of an incident wave; the subscripts of a typical S-parameter S refer to the
ij
output and input ports related by the S-parameter, which may vary with frequency and apply at a specified set of
input and output reference planes; may imply the performance of an EMC filtering device.
EXAMPLE  The S-parameters for a two-port circuit are defined as follows:

S S
 
11 12
S =
 
S S
 21 22
where
S and S are the reflection coefficients at port 1 or 2 of a circuit component, respectively, where the
11 22
opposite port is terminated with a port reference impedance (for example 50 Ω); and
S and S are the transmission coefficients representing the ratio of the signal transmitted to port 2 to that
21 12
incident from port 1, and vice versa, respectively. The value of S is a good indicator of the
noise suppression for a signal passing through this component.
NOTE 2 It is important to evaluate the degradation of a signal waveform caused by variation in the S-parameters
with the frequency.
3.1.14
test circuits
3.1.14.1
asymmetrical (common mode) test circuit
test circuit in which all input lines of a filter under test are connected to a signal generator
with all output lines being connected to a receiver
NOTE The test circuit used to measure the asymmetrical (common mode) insertion loss of a filter is shown in
Figure 5.
3.1.14.2
symmetrical (differential mode) test circuit
test circuit in which the signal is fed across a pair of input lines of a filter under test, and the
corresponding pair of output lines is connected to a receiver; the other lines are not
terminated
NOTE An example of the test circuit used to measure the symmetrical (differential mode) insertion loss of a filter is
shown in Figure 6; all combinations of each two lines of the filter are measured; ground or PE (protective earth)
terminals are not considered.
3.1.14.3
unsymmetrical test circuit
test circuit in which the signal is fed to an input line of a filter under test, and the
corresponding output line is connected to a receiver; the other input and output lines are
terminated in specified impedances

– 12 – CISPR 17  IEC:2011
NOTE An example of the test circuit used to measure the unsymmetrical insertion loss of a filter is shown in
Figure 7; each line of the filter is measured with all unused lines terminated to reference potential with Z or Z .
11 12
3.2 Abbreviations
CMCC Common-mode choke coils
DUT Device under test
EM Electromagnetic
EMC Electromagnetic compatibility
e.m.f. Electromotive force
GND Ground
HPF High-pass filter
L Line
N Neutral
PE Protective earth
RF Radio frequency
SMD Surface mount device
TRL Thru/Reflect/Line
VNA Vector network analyzer
VSWR Voltage-standing wave ratio
4 Classification of EMC filtering devices
Examples of EMC filtering devices and their applicable measurement methods are shown in
Table 1.
CISPR 17  IEC:2011 – 13 –
Table 1 – Examples of EMC filtering devices
Parameters to be measured and
Examples
measurement method
Filter type Symbol or circuit diagram
Insertion S-
Outer view Impedance
loss parameter
Ferrite cores
and
Clause 5 Clause 6 Clause 7
absorbing
clamps
Chokes,
inductors and Clause 5 Clause 6 Clause 7

beads
Non-
feedthrough Clause 5 Clause 6 Clause 7

capacitors
Feedthrough
Clause 5 – Clause 7
capacitors
Three-
terminal Clause 5 – Clause 7
capacitors
Common
mode choke Clause 7 Clause 6 Clause 7
coils
Annex E of
Resistors CISPR – –
12:2007
Filter
Clause 5 – –
(multiple
a
lines with
GND)
a
one line without neutral, multiple lines with or without neutral.

– 14 – CISPR 17  IEC:2011
4.1 Insertion loss
4.1.1 Insertion loss calculation
The standard test method uses a calibrated 50-Ω signal source and a 50-Ω receiver. The
insertion loss is determined by the following formula:
V
o
a = 20log
(1)
e
2V
where
a is the insertion loss (dB),
e
V is the open circuit output voltage of a 50-Ω signal generator, and
o
V is the voltage at the output of the filter circuit.
Theory and background information on insertion loss measurement are presented in Annex E.
4.1.2 Asymmetrical (common) mode
Because all input and output lines are connected in parallel, only one set of values for the
asymmetrical insertion loss is measured (see 5.2.3).
4.1.3 Symmetrical (differential) mode
Each pair of input lines shall be measured against the corresponding output lines; one set of
insertion loss values or curves is measured for each of the line pairs. Ground or PE
(protective earth) terminals are not considered (see 5.2.4).
For example, for a three-line filter with neutral line (line terminals L1, L2, L3, neutral terminal
N and PE) the following measurements shall be performed: L1 to L2, L1 to L3, L2 to L3, L1 to
N, L2 to N, L3 to N (six measurements in total).
Symmetrical mode measurements cannot be applied to single-line filters or components.
4.1.4 Unsymmetrical mode
Each input line shall be measured against the corresponding output line with all unused lines
being terminated by specified impedance (normally 50 Ω) to reference potential (see 5.2.5).
For example, for a three-line filter with neutral line (line terminals L1, L2, L3, neutral terminal
N and PE) the following measurements shall be performed: L1 with L2, L3 and N terminated,
L2 with L1, L3 and N terminated, L3 with L1, L2 and N terminated and N with L1, L2 and L3
terminated.
Unsymmetrical mode measurements cannot be applied to one-line filters or components.
4.2 Impedance
An EMC filtering device of certain impedance is often inserted into a circuit to reduce the
unwanted current. The suppression characteristics may be determined by the impedance
characteristics of both the inserted device and the original circuit.
The impedance of the device, and therefore the suppression characteristics, vary with
frequency, bias condition, etc. Consequently, the impedance should be measured at various

CISPR 17  IEC:2011 – 15 –
frequencies. This frequency dependence is used to design an EMC filtering device. The
impedance measurements may be applied in the frequency range from 9 kHz to 3 GHz.
4.3 S-parameters
4.3.1 General
The EMC characteristics of a device are determined by the S-parameters of both the inserted
device and the original circuit.
The S-parameters of the device, and therefore the suppression characteristics, vary with
frequency, bias condition, etc. Consequently, S-parameters should be measured at various
frequencies. This frequency dependence is used to design an EMC filtering device. The S-
parameter measurements may be applied in the frequency range from around 100 MHz to
6 GHz.
4.3.2 Two-port S-parameters
The characteristics of two-terminal components (inductors, capacitors, etc.) can be evaluated
in terms of the two-port S-parameters using a test fixture as shown in Figure 1. Three-terminal
filters (feedthrough capacitors, other three-terminal filters) are also evaluated using a test
fixture as shown in Figure 2.
Two configurations for connecting the two-terminal devices and fixture are possible: one using
a series connection and one using a shunt connection. One of these configurations should be
chosen according to the application of the device. The series connection is normally selected
for inductors, and the shunt connection is chosen for capacitors. However, when capacitors
are used as high-pass filters (HPF), the series connection should be selected.
1 2
DUT
Port 1 Port 2
Port 1 Port 2 DUT
1'(GND) 2'(GND) 1'(GND) 2'(GND)

a) Series connection, for high impedance b) Shunt connection, for low impedance DUT
DUT compared to 50 Ω compared to 50 Ω
Figure 1 – Measurement arrangement for S-parameters of a two-terminal device
1 2
DUT
Port 1 Port 2
1’ (GND) 2’ (GND)
Figure 2 – Measurement arrangement for S-parameters of a three-terminal device

– 16 – CISPR 17  IEC:2011
The characteristic impedance of the S-parameter test fixture should be matched to the port
impedance of a network analyzer (50 Ω).
When the test fixture is matched to 50 Ω, the insertion loss (a ) in dB can be given by
e
a = −20log | S |
e ij (2)
The return loss (a ) in dB is defined as
r
a = −20log S
(3)
r ii
4.3.3 Four-port S-parameters
The characteristics of a four-port device (illustrated in Figure 3), such as common-mode
choke coils (CMCC) may be evaluated using the four port S-parameters (see Annex G).

1’(GND) 2’(GND)
Port 2
Port 1
DUT
Port 3
Port 4
4’(GND)
3’(GND)
Figure 3 – Measurement arrangement for four-port S-parameters
Measurements using a vector network analyzer (VNA) yield S-parameters S for the four ports.
ij
However, the common/differential-mode S-parameters derived from the measured
S-parameters are more useful for characterizing the device (hereafter referred to as the
mixed-mode S-parameters) [5] . These are defined by the following formula:

S S S S 
cc11 cc12 cd11 cd12
 
S S  S S S S
cc cd cc21 cc22 cd21 cd22
 
S ' = =
 
 
S S S S S S
dc dd dc11 dc12 dd11 dd12
 
 
S S S S
dc21 dc22 dd21 dd22
 
S + S + S + S S + S + S + S S + S − S − S S + S − S − S
 
11 31 13 33 12 32 14 34 11 31 13 33 12 32 14 34
 
S + S + S + S S + S + S + S S + S − S − S S + S − S − S
21 41 23 43 22 42 24 44 21 41 23 43 22 42 24 44
 
=
 
S − S + S − S S − S + S − S S − S − S + S S − S − S + S
11 31 13 33 12 32 14 34 11 31 13 33 12 32 14 34
 
S − S + S − S S − S + S − S S − S − S + S S − S − S + S
 21 41 23 43 22 42 24 44 21 41 23 43 22 42 24 44 
(4)
The sub-matrices in the above formula express conversion characteristics between the modes,
where
—————————
Figures in square brackets refer to the Bibliography.

CISPR 17  IEC:2011 – 17 –
S is the matrix for conversion from common mode to common mode,
cc
S is the matrix for conversion from differential mode to common mode,
cd
S is the matrix for conversion from common mode to differential mode, and
dc
S is the matrix for conversion from differential mode to differential mode.
dd
Each sub-matrix has four elements. For example, for sub-matrix S :
cc
S is the reflection coefficient at the input,

cc11
S is the transmission coefficient from the output to input,
cc12
S is the transmission coefficient from the input to output, and
cc21
S is the reflection coefficient at the output.
cc22
The reference impedances of the common mode and differential mode are half of and double
the actual port reference impedance, respectively. For example, when the original S-
parameters are measured with a 50-Ω instrument, then the common- and differential-mode
port reference impedances become 25 Ω and 100 Ω, respectively.
5 Insertion loss measurement
5.1 General
This clause describes the methods for performing insertion loss measurement of a DUT. In
addition, the two-port S-parameters measurement described in 4.3.2 may be us
...