CISPR 16-2:2003

INTERNATIONAL
CISPR
ELECTROTECHNICAL
16-2
COMMISSION
Second edition
2003-07
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE
Specification for radio disturbance and
immunity measuring apparatus and methods –
Part 2:
Methods of measurement of
disturbances and immunity
Spécification pour les appareils et méthodes de mesure
des perturbations radioélectriques et de l'immunité –
Partie 2:
Méthodes de mesure des perturbations
et de l'immunité
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INTERNATIONAL
CISPR
ELECTROTECHNICAL
16-2
COMMISSION
Second edition
2003-07
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE
Specification for radio disturbance and
immunity measuring apparatus and methods –
Part 2:
Methods of measurement of
disturbances and immunity
Spécification pour les appareils et méthodes de mesure
des perturbations radioélectriques et de l'immunité –
Partie 2:
Méthodes de mesure des perturbations
et de l'immunité
 IEC 2003  Copyright - all rights reserved
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– 2 – CISPR 16-2  IEC:2003(E)

CONTENTS
FOREWORD . 6

SECTION 1: GENERAL
1.1 Scope . 8

1.2 Normative references . 8

1.3 Definitions. 8

SECTION 2: DISTURBANCE MEASUREMENTS
2.1 Types of disturbance to be measured .12
2.1.1 Types of disturbance .12
2.1.2 Detector functions.13
2.2 Connection of measuring equipment.13
2.2.1 Connection of associated equipment.13
2.2.2 Connections to RF reference ground.13
2.2.3 Connection between the EUT and the artificial mains network .13
2.3 General measurement requirements and conditions.14
2.3.1 Disturbance not produced by the equipment under test .14
2.3.2 Measurement of continuous disturbance .14
2.3.3 Operating conditions of the EUT .15
2.3.4 Interpretation of measuring results.15
2.3.5 Measurement times and scan rates for continuous disturbance .16
2.4 Measurement of disturbances conducted along leads, 9 kHz to 30 MHz .22
2.4.1 Introduction .22
2.4.2 Measuring equipment (receivers, etc.) .22
2.4.3 Associated measuring equipment.23
2.4.4 Equipment test configuration.25
2.4.5 System test configuration for conducted emissions measurements.41
2.4.6 In situ measurements .44
2.5 Measurements using the absorbing clamp, 30 MHz to 1 000 MHz .46
2.5.1 General .46
2.5.2 Measurements.46
2.6 Measurement of radiated disturbances .47

2.6.1 Introduction .47
2.6.2 Field-strength measurements in the frequency range 9 kHz to 1 GHz .48
2.6.3 Field-strength measurements in the frequency range 1 GHz to 18 GHz .56
2.6.4 Substitution method of measurement in the frequency range of 30 MHz
to 18 GHz .58
2.6.5 Measurements of in situ equipment.60
2.6.6 Measurement in a loop antenna system .67
SECTION 3: IMMUNITY MEASUREMENTS
3.1 Immunity test criteria and general measurement procedures.69
3.1.1 General measurement method.69
3.1.2 Immunity degradation criteria.71
3.1.3 Product specification details .71

CISPR 16-2  IEC:2003(E) – 3 –

3.2 Method of measurement of immunity for conducted signals.72

3.2.1 Coupling units.74

3.2.2 Measurement set-up .74

3.2.3 Method of measurement of input immunity .74

3.3 Method of measurement of immunity to radiated electric field interference .76

3.3.1 Measurements using the TEM mode .76

3.3.2 Measurement using absorber-lined shielded rooms .79

3.3.3 Measurements using an open area test site (OATS).82

SECTION 4: AUTOMATED MEASUREMENTS
4.1 Automated measurements Automated measurement of emissions .84
4.1.1 Introduction: Precautions for automating measurements .84
4.1.2 Generic measurement procedure .84
4.1.3 Prescan measurements .85
4.1.4 Data reduction .87
4.1.5 Emission maximization and final measurement .87
4.1.6 Post processing and reporting.88
SECTION 5: FACTORS INFLUENCING MEASUREMENT ACCURACY
5.1 Factors influencing measurement accuracy .88
5.1.1 Accuracy of measurements.89
5.1.2 Avoidance of extraneous signals and effects .89
Annex A (informative) Guidelines to connection of electrical equipment to the artificial
mains network (see 2.2) .90
Annex B (informative) Use of spectrum analyzers and scanning receivers (see 2.3) .98
Annex C (informative) Historical background to the method of measurement of the
interference power produced by electrical household and similar appliances in
the VHF rang (see 3.1) .101
Annex D (informative) Decision tree for use of detectors for conducted measurements
(see 2.4.2.1).103
Annex E (informative) Measurement of disturbances in the presence of ambient
emissions.105
Annex F (informative) Example of the uncertainty budget .118

Figure 1 – Measurement of a combination of a CW signal (“NB”) and an impulsive
signal (“BB”) using multiple sweeps with maximum hold. 19
Figure 2 – Example of a timing analysis . 20
Figure 3 – A broadband spectrum measured with a stepped receiver . 21
Figure 4 – Intermittent narrowband disturbances measured using fast short repetitive
sweeps with maximum hold function to obtain an overview of the emission spectrum . 21
Figure 5 – Test configuration: table-top equipment for conducted disturbance
measurements on power mains (see 2.4.4.1 and 2.4.4.2). 26
Figure 6 – Optional test configuration for an EUT with only a power cord attached
(see 2.4.4.1). 28
Figure 7 – Test configuration: floor-standing equipment (see 2.4.4.1 and 2.4.5.2.2). 29
Figure 8 – Test configuration: floor-standing and table-top equipment (see 2.4.4.1 and
2.4.5.2.2) . 30

– 4 – CISPR 16-2  IEC:2003(E)

Figure 9 – Schematic of conducted disturbance voltage test configuration (see 2.4.4.1

and 2.4.5.2.2). 31

Figure 10 – Equivalent circuit for measurement of common mode disturbance voltage

for Class I (grounded) EUT (see 2.4.4.2.1). 32

Figure 11 – Equivalent circuit for measurement of common mode disturbance voltage

for Class II (grounded) EUT (see 2.4.4.2.2). 34

Figure 12 – RC element for artificial hand (see 2.4.4.2.3). 35

Figure 13 – Portable electric drill with artificial hand (see 2.4.4.2.3). 35

Figure 14 – Portable electric saw with artificial hand (see 2.4.4.2.3) . 35

Figure 15 – Schematic diagram for simulation of telecommunication lines (T-1 network or

telecom impedance simulation network) (see 2.4.4.3.2) . 38
Figure 16 – Measuring example for voltage probes (see 2.4.4.4.1) . 39
Figure 16a – Measurement arrangement for two-terminal regulating controls . 39
Figure 17 – Test configuration for absorbing clamp (see 2.5.2) . 47
Figure 18 – Concept of electric field strength measurements made on an open area test site
with the direct and reflective rays arriving at the receiving antenna (see 2.6.2.2) . 48
Figure 19 – Typical test set-up in FAR, where a, b, c and e depend on the room
performance. 52
Figure 20 – Typical test set-up for table-top equipment within the test volume of a FAR . 54
Figure 21 – Typical test set-up for floor standing equipment within the test volume
of a FAR. 55
Figure 22 – Method of measurement – Substitution method (see 2.6.4.1 and 2.6.4.3). 59
Figure 23 – Determination of the transition distance. 66
Figure 24 – Concept of magnetic field induced current measurements made with the loop
antenna system (see 2.6.6) . 68
Figure 25 – Fundamental concept of immunity measurement (see 3.1.1). 70
Figure 26 – General principle of the current-injection method (see 3.2) . 73
Figure 27 – Measuring set-up for input immunity measurement of sound broadcast
receivers (see 3.2.3.1). 75
Figure 28 – Measuring set-up for input immunity measurement of television broadcast
receivers (see 3.2.3.2). 76
Figure 29 – Example of the arrangement of an open stripline TEM device in combination
with absorbing panels inside a screened room with dimensions 3 m × 3,5 m (see 3.3.1.1) . 77
Figure 30 – Measuring set-up for the immunity of broadcast receivers to ambient fields
in the frequency range of 0,15 MHz – 150 MHz (see 3.3.1.1) . 78
Figure 31 – Measuring circuit for the immunity of sound broadcast receivers to ambient

fields (see 3.3.1.1.1). 79
Figure A.1 (see A.2.1) .90
Figure A.2 (see A.2.1) .91
Figure A.3 (see A.2.2) .91
Figure A.4 (see A.2.2) .91
Figure A.5 (see A.2.3.1) . 92
Figure A.6 (see A.2.3.2) . 92
Figure A.7 (see A.2.3.3) . 93
Figure A.8 – AMN configurations (see A.5) . 97
Figure D.1 – Decision tree for optimizing speed of conducted disturbance measurements
with peak, quasi-peak and average detectors. 103
Figure E.1 – Flow diagram for the selection of bandwidths and detectors and the
estimated measurement errors due to that selection . 107
Figure E.2 – Relative difference in adjacent emission amplitudes during preliminary testing 108

CISPR 16-2  IEC:2003(E) – 5 –

Figure E.3 – Disturbance by an unmodulated signal (dotted line). 109

Figure E.4 – Disturbance by an amplitude-modulated signal (dotted line) . 110

Figure E.5 – Indication of an amplitude-modulated signal as a function of modulation
frequency with the QP detector in CISPR bands B, C and D . 110

Figure E.6 – Indication of a pulse-modulated signal (pulse width 50 µs) as a function

of pulse repetition frequency with peak, QP and average detectors . 111

Figure E.7 – Disturbance by a broadband signal (dotted line) . 112

Figure E.8 – Unmodulated EUT disturbance (dotted line) . 112

Figure E.9 – Amplitude-modulated EUT disturbance (dotted line) . 113

Figure E.10 – Increase of peak value with superposition of two unmodulated signals
(U – level of ambient emission; U – level of EUT disturbance) . 115
a i
Figure E.11 – Determination of the amplitude of the disturbance signal by means of
the amplitude ratio d and the factor i. 115
Figure E.12 – Increase of average indication measured with a real receiver and
calculated from equation (E.8) . 116
Table 1 – Minimum scan times for the three CISPR bands with peak and quasi-peak
detectors . 16
Table 2 – Recommended antenna heights to guarantee signal interception (for prescan)
in the frequency range 30 MHz to 1 000 MHz . 86
Table A.1 (see A.4.2). 95
Table A.2 (see A.4.2). 96
Table E.1 – Combinations of EUT disturbance and ambient emissions . 106
Table E.2 – Measurement error depending on the detector type and on the combination
of ambient and disturbing signal spectra . 117
Table F.1 – Uncertainty budget for emission measurements in a 3 m FAR. 118

– 6 – CISPR 16-2  IEC:2003(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE

____________
SPECIFICATION FOR RADIO DISTURBANCE AND IMMUNITY

MEASURING APPARATUS AND METHODS –

Part 2: Methods of measurement of

disturbances and immunity
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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(ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard CISPR 16-2 has been prepared by CISPR, subcommittee A: Radio inter-
ference measurements and statistical methods.
This second edition cancels and replaces the first edition published in 1996, Amendment 1
(1999) and Amendment 2 (2002).
The document CISPR/A/443/FDIS, circulated to the National Committees as Amendment 3, led
to the publication of the new edition.

CISPR 16-2  IEC:2003(E) – 7 –

The text of this standard is based on the first edition, its Amendment 1 and Amendment 2 and
on the following documents:
FDIS Report on voting
CISPR/A/443/FDIS CISPR/A/463/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.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

This standard should be read in conjunction with CISPR 16-1.
The committee has decided that the contents of this publication will remain unchanged until
2004. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 8 – CISPR 16-2  IEC:2003(E)

SPECIFICATION FOR RADIO DISTURBANCE AND IMMUNITY

MEASURING APPARATUS AND METHODS –

Part 2: Methods of measurement of disturbances and immunity

1 Section 1: General
1.1 Scope
This part of CISPR 16 specifies the methods of measurement of EMC phenomena in the
frequency range 9 kHz to 18 GHz.
1.2 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 60083:1997, Plugs and socket-outlets for domestic and similar general use standardized in
member countries of IEC – Standards
IEC 60364-4: Electrical installations of buildings – Part 4: Protection for safety
CISPR 11:1997, Industrial, scientific and medical (ISM)radio-frequency equipment – Electro-
magnetic disturbance characteristics – Limits and methods of measurement
CISPR 13:2001, Sound and television broadcast receivers and associated equipment – Radio
disturbance characteristics – Limits and methods of measurement
CISPR 14-1:2000, Electromagnetic compatibility – Requirements for household appliances,
electric tools and similar apparatus – Part 1: Emission
CISPR 16-1:1999, Specification for radio disturbance and immunity measuring apparatus and
methods – Part 1: Radio disturbance and immunity measuring apparatus
CISPR 22:1997, Information technology equipment – Radio disturbance characteristics – Limits
and methods of measurement
ITU-R Recommendation BS.468-4: Measurement of audio-frequency noise voltage level in
sound broadcasting
1.3 Definitions
For the purpose of this part of CISPR 16, the definitions of IEC 60050(161) apply, as well as
the following:
1.3.1
associated equipment
1) Transducers (e.g. probes, networks and antennas) connected to a measuring receiver or
test generator
2) Transducers (e.g. probes, networks, antennas) which are used in the signal or disturbance
transfer between an EUT and measuring equipment or a (test-) signal generator
1.3.2
EUT
the equipment (devices, appliances and systems) subjected to EMC (emission and immunity)
compliance tests
CISPR 16-2  IEC:2003(E) – 9 –

1.3.3
product publication
publication specifying EMC requirements for a product or product family, taking into account

specific aspects of such a product or product family

1.3.4
emission limit (from a disturbing source)

the specified maximum emission level of a source of electromagnetic disturbance

[IEV 161-03-12]
1.3.5
immunity limit
the specified minimum immunity level
[IEV 161-03-15]
1.3.6
ground reference
a connection that constitutes a defined parasitic capacitance to the surrounding of an EUT and
serves as reference potential
NOTE See also IEV 161-04-36.
1.3.7
(electromagnetic) emission
the phenomenon by which electromagnetic energy emanates from a source
[IEV 161-01-08]
1.3.8
Immunity (to a disturbance)
the ability of a device, equipment or system to perform without degradation in the presence of
an electromagnetic disturbance
[IEV 161-01-20]
1.3.9
coaxial cable
a cable containing one or more coaxial lines, typically used for a matched connection of
associated equipment to the measuring equipment or (test-)signal generator providing a
specified characteristic impedance and a specified maximum allowable cable transfer
impedance
1.3.10
common mode (asymmetrical disturbance voltage)
the RF voltage between the artificial midpoint of a two-conductor line and reference ground, or
in case of a bundle of lines, the effective RF disturbance voltage of the whole bundle (vector
sum of the unsymmetrical voltages) against the reference ground measured with a clamp
(current transformer) at a defined terminating impedance
NOTE See also IEV 161-04-09.
1.3.11
common mode current
the vector sum of the currents flowing through two or more conductors at a specified cross-
section of a “mathematical” plane intersected by these conductors
1.3.12
differential mode voltage; symmetrical voltage
the RF disturbance voltage between the wires of a two conductor line
[IEV 161-04-08, modified]
– 10 – CISPR 16-2  IEC:2003(E)

1.3.13
differential mode current
half the vector difference of the currents flowing in any two of a specified set of active

conductors at a specified cross-section of a “mathematical” plane intersected by these

conductors
1.3.14
unsymmetrical mode (V-terminal voltage)

the voltage between a conductor or terminal of a device, equipment or system and a specified

ground reference. For the case of a two-port network, the two unsymmetrical voltages are
given by:
a) the vector sum of the asymmetrical voltage and half of the symmetrical voltage; and
b) the vector difference between the asymmetrical voltage and half of the symmetrical voltage.
NOTE See also IEV 161-04-13.
1.3.15
measuring receiver
a receiver for the measurement of disturbances with different detectors
NOTE The receiver is specified according to CISPR 16-1.
1.3.16
test configuration
gives the specified measurement arrangement of the EUT in which an emission or immunity
level is measured
NOTE The emission level or immunity level is measured as required by IEV 161-03-11, IEV 161-03-12, IEV 161-03-14 and
IEV 161-03-15, definitions of emission level and immunity level.
1.3.17
artificial network (AN)
an agreed reference load (simulation) impedance presented to the EUT by actual networks
(e.g., extended power or communication lines) across which the RF disturbance voltage is
measured
1.3.18
artificial mains network (AMN)
a network inserted in the supply mains lead of apparatus to be tested which provides, in a
given frequency range, a specified load impedance for the measurement of disturbance
voltages and which may isolate the apparatus from the supply mains in that frequency range
[IEV 161-04-05]
1.3.19
weighting (quasi-peak detection)
the repetition-rate dependent conversion of the peak-detected pulse voltages to an indication
corresponding to the psychophysical annoyance of pulsive disturbances (acoustically or
visually) according to the weighting characteristics, or alternatively gives the specified manner
in which an emission level or an immunity level is evaluated
NOTE 1 The weighting characteristics are specified in CISPR 16-1.
NOTE 2 The emission level or immunity level is evaluated as required by IEC 60050(161) definitions of level (see
IEV 161-03-01, IEV 161-03-11 and IEV 161-03-14).

CISPR 16-2  IEC:2003(E) – 11 –

1.3.20
continuous disturbance
RF disturbance with a duration of more than 200 ms at the IF-output of a measuring receiver,

which causes a deflection on the meter of a measuring receiver in quasi-peak detection mode

which does not decrease immediately

[IEV 161-02-11, modified]
NOTE The measuring receiver is specified in CISPR 16-1.

1.3.21
discontinuous disturbance
for counted clicks, disturbance with a duration of less than 200 ms at the IF-output of a
measuring receiver, which causes a transient deflection on the meter of a measuring receiver
in quasi-peak detection mode
NOTE 1 For impulsive disturbance, see IEV 161-02-08.
NOTE 2 The measuring receiver is specified in CISPR 16-1.
1.3.22
fully anechoic chamber (FAC) or fully anechoic room (FAR)
shielded enclosure, the internal surfaces of which are lined with radio frequency absorbing
material (i.e. RF absorber), that absorbs electromagnetic energy in the frequency range of
interest. The Fully Absorber-Lined Room is intended to simulate a free space environment
where only the direct ray from the transmitting antenna reaches the receiving antenna. All
indirect and reflected waves are minimised with the use of proper absorbing material on all
walls, the ceiling and the floor of the FAR
1.3.23
measurement time
T
m
the effective, coherent time for a measurement result at a single frequency (sometimes also
called dwell time)
– for the peak detector, the effective time to detect the maximum of the signal envelope,
– for the quasi-peak detector, the effective time to measure the maximum of the weighted
envelope
– for the average detector, the effective time to average the signal envelope
– for the r.m.s. detector, the effective time to determine the r.m.s. of the signal envelope
1.3.24
sweep
a continuous frequency variation over a given frequency span

1.3.25
scan
a continuous or stepped frequency variation over a given frequency span
1.3.26
sweep or scan time
T
s
the time between start and stop frequencies of a sweep or scan
1.3.27
span
ΔΔΔΔf
difference between stop and start frequencies of a sweep or scan

– 12 – CISPR 16-2  IEC:2003(E)

1.3.28
sweep or scan rate
the frequency span divided by the sweep or scan time

1.3.29
number of sweeps per time unit (e.g. per second)

n
s
1/(sweep time + retrace time)
1.3.30
observation time
T
o
the sum of measurement times T on a certain frequency in case of multiple sweeps. If n is the
m
number of sweeps or scans, then T = n × T
o m
1.3.31
total observation time
T
tot
the effective time for an overview of the spectrum (either single or multiple sweeps). If c is the
number of channels within a scan or sweep, then T = c × n × T
tot m
2 Section 2: Disturbance measurements
2.1 Types of disturbance to be measured
This subclause describes the classification of different types of disturbance and the detectors
appropriate for their measurement.
2.1.1 Types of disturbance
For physical and psychophysical reasons, dependent on the spectral distribution, measuring
receiver bandwidth, the duration, rate of occurrence, and degree of annoyance during the
assessment and measurement of radio disturbance, distinction is made between the following
types of disturbance:
a) narrowband continuous disturbance, i.e. disturbance on discrete frequencies as, for
example, the fundamentals and harmonics generated with the intentional application of RF
energy with ISM equipment, constituting a frequency spectrum consisting only of individual
spectral lines whose separation is greater than the bandwidth of the measuring receiver so
that during the measurement only one line falls into the bandwidth in contrast to b);

b) broadband continuous disturbance, which normally is unintentionally produced by the
repeated impulses of, for example, commutator motors, and which have a repetition
frequency which is lower than the bandwidth of the measuring receiver so that during the
measurement more than one spectral line falls into the bandwidth; and
c) broadband discontinuous disturbance is also generated unintentionally by mechanical or
electronic switching procedures, for example by thermostats or programme controls with a
repetition rate lower than 1 Hz (click-rate less than 30/min).
The frequency spectra of b) and c) are characterized by having a continuous spectrum in the
case of individual (single) impulses and a discontinuous spectrum in case of repeated
impulses, both spectra being characterized by having a frequency range which is wider than
the bandwidth of the measuring receiver specified in CISPR 16-1.

CISPR 16-2  IEC:2003(E) – 13 –

2.1.2 Detector functions
Depending on the types of disturbance, measurements may be carried out using a measuring

receiver with:
a) an average detector generally used in the measurement of narrowband disturbance and
signals, and particularly to discriminate between narrowband and broadband disturbance;

b) a quasi-peak detector provided for the weighted measurement of broadband disturbance for

the assessment of audio annoyance to a radio listener, but also usable for narrowband
disturbance;
c) a peak detector which may be used for either broadband or narrowband disturbance

measurement.
Measuring receivers incorporating these detectors are specified in CISPR 16-1.
2.2 Connection of measuring equipment
This subclause describes the connection of measuring equipment, measuring receivers and
associated equipment such as artificial networks, voltage and current probes, absorbing
clamps and antennas.
2.2.1 Connection of associated equipment
The connecting cable between the measuring receiver and the associated equipment shall be
shielded and its characteristic impedance shall be matched to the input impedance of the
measuring receiver.
The output of the associated equipment shall be terminated with the prescribed impedance.
2.2.2 Connections to RF reference ground
The artificial mains network (AMN) shall be connected to the reference ground by a low RF
impedance, e.g. by direct bonding of the case of the AMN to the reference ground or reference
wall of a shielded room, or with a low impedance conductor as short and as wide as practical
(maximum length to width ratio is 3:1).
Terminal voltage measurements shall be referenced only to the reference ground. Ground
loops (common impedance coupling) shall be avoided. This should also be observed for
measuring apparatus (e.g. measuring receivers and connected associated equipment, such as
oscilloscopes, analyzers, recorders, etc.) fitted with a protective earth conductor (PE) of
Protection Class I equipment. If the PE connection of the measuring apparatus and the PE
connection of the power mains to the reference ground do not have RF isolation from the

reference ground, the necessary RF isolation shall be provided by means such as RF chokes
and isolation transformers, or if applicable, by powering the measuring apparatus from
batteries, so that the RF connection of the measuring apparatus to the reference ground is
made via only one route.
For the treatment of PE connection of the EUT to the reference ground, see Clause A.4.
Stationary test configurations do not require a connection with the protective earth conductor if
the reference ground is connected directly and meets the safety requirements for protective
earth conductors (PE connections).
2.2.3 Connection between the EUT and the artificial mains network
General guidelines for the selection of grounded and non-grounded connections of the EUT to
the AMN are discussed in Annex A.

– 14 – CISPR 16-2  IEC:2003(E)

2.3 General measurement requirements and conditions

Radio disturbance measurements shall be:

a) reproducible, i.e. independent of the measurement location and environmental conditions,
especially ambient noise;
b) free from interactions, i.e. the connection of the EUT to the measuring equipment shall

neither influence the function of the EUT nor the accuracy of the measurement equipment.

These requirements may be met by observing the following conditions:

c) existence of a sufficient signal-to-noise ratio at the desired measurement level, e.g. the

level of the relevant disturbance limit;

d) having a defined measuring set-up, termination and operating conditions of the EUT;
e) having a sufficiently high impedance of the probe at the measuring point, in the case of
voltage probe measurements;
f) when using a spectrum analyzer or scanning receiver due considerations shall be given to
its particular operating and calibration requirements.
2.3.1 Disturbance not produced by the equipment under test
The measurement signal-to-noise ratio with respect to ambient noise shall meet the following
requirements. Should the spurious noise level exceed the required level, it shall be recorded
in the test report.
2.3.1.1 Compliance testing
A test site shall permit emissions from the EUT to be distinguished from ambient noise. The
ambient noise level should preferably be 20 dB, but at least be 6 dB below the desired
measurement level. For the 6 dB condition, the apparent disturbance level from the EUT is
increased by up to 3,5 dB. The suitability of the site for required ambient level may be
determined by measuring the ambient noise level with the test unit in place but not operating.
In the case of compliance measurement according to a limit, the ambient noise level is
permitted to exceed the preferred –6 dB level provided that the level of both ambient noise and
source emanation combined does not exceed the specified limit. The EUT is then considered
to meet the limit. Other actions can also be taken; for example, reduce the bandwidth for
narrowband signals and/or move the antenna closer to the EUT.
NOTE If both the ambient field strength and field strength of ambient and EUT are measured separately, it may be
possible to provide an estimate of the EUT field strength to a quantifiable level of uncertainty. Reference is made
in this respect in Annex E of this standard and in Annex C of CISPR 11.
2.3.2 Measurement of continuous disturbance

2.3.2.1 Narrowband continuous disturbance
The measuring set shall be kept tuned to the discrete frequency under investigation and
returned if the frequency fluctuates.
2.3.2.2 Broadband continuous disturbance
For the assessment of broadband continuous disturbance the level of which is not steady, the
maximum reproducible measurement value shall be found. See 2.3.4.1 for further details.

CISPR 16-2  IEC:2003(E) – 15 –

2.3.2.3 Use of spectrum analyzers and scanning receivers

Spectrum analyzers and scanning receivers are useful for disturbance measurements,

particularly in order to reduce measuring time. However, special consideration must be given to

certain characteristics of these instruments, which include: overload, linearity, selectivity,

normal response to pulses, frequency scan rate, signal interception, sensitivity, amplitude

accuracy and peak, average and quasi-peak detection. These characteristics are considered

in Annex B.
2.3.3 Operating conditions of the EUT

The EUT shall be operated under the following conditions:
2.3.3.1 Normal load conditions
The normal load conditions shall be as defined in the product specification relevant to the EUT,
and for EUTs not so covered, as indicated in the manufacturer’s instructions.
2.3.3.2 The time of operation
The time of operation shall be, in the case of EUTs with a given rated operating time, in
accordance with the marking; in all other cases, the time is not restricted.
2.3.3.3 Running-in time
No specific running-in time, prior to testing, is given, but the EUT shall be operated for a
sufficient period to ensure that the modes and conditions of operation are typical of those
during the life of the equipment. For some EUTs, special test conditions may be prescribed in
the relevant equipment publications.
2.3.3.4 Supply
The EUT shall be operated from a supply having the rated voltage of the EUT. If the level of
disturbance varies considerably with the supply voltage, the measurements shall be repeated
for supply voltages over the range of 0,9 to 1,1 times the rated voltage. EUTs with more than
one rated voltage shall be tested at the rated voltage which causes maximum disturbance.
2.3.3.5 Mode of operation
The EUT shall be oper
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