CISPR TR 16-4-5:2006/AMD2:2021

CISPR TR 16-4-5 ®
Edition 1.0 2021-10
TECHNICAL
REPORT
colour
inside
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE

AMENDMENT 2
Specification for radio disturbance and immunity measuring apparatus and
methods –
Part 4-5: Uncertainties, statistics and limit modelling – Conditions for the use of
alternative test methods
CISPR TR 16-4-5:2006-10/AMD2:2021-10(en)

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CISPR TR 16-4-5 ®
Edition 1.0 2021-10
TECHNICAL
REPORT
colour
inside
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE

AMENDMENT 2
Specification for radio disturbance and immunity measuring apparatus and

methods –
Part 4-5: Uncertainties, statistics and limit modelling – Conditions for the use of

alternative test methods
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.100.10; 33.100.20 ISBN 978-2-8322-9844-2

– 2 – CISPR TR 16-4-5:2006/AMD2:2021
 IEC 2021
FOREWORD
This amendment has been prepared by subcommittee CISPR A: Radio-interference measure-
ments and statistical methods, of IEC technical committee CISPR: International special com-
mittee on radio interference.
The text of this amendment is based on the following documents:
DTR Report on voting
CIS/A/1321/DTR CIS/A/1324/RVDTR

Full information on the voting for the approval of this amendment can be found in the report on
voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website under "http://web-
store.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• withdrawn,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 document using a colour printer.

_____________
1 Scope
Add, in the second sentence, the following new text “and total radiated power” to the
parentheses to read: “i.e. field strength and total radiated power”.
2 Normative references
Add the following new reference to the existing list:
CISPR 16-1-1:2019, Specification for radio disturbance and immunity measuring apparatus and
methods – Part 1-1: Radio disturbance and immunity measuring apparatus – Measuring appa-
ratus
Delete the existing reference to CISPR 16-4-1, modified by Amendment 1.
Replace the existing reference to CISPR 16-4-2:2003 with the following:

 IEC 2021
CISPR 16-4-2:2011, Specification for radio disturbance and immunity measuring apparatus and
methods – Part 4-2: Uncertainties, statistics and limit modelling – Measurement instrumentation
uncertainty
CISPR 16-4-2:2011/AMD1:2014
CISPR 16-4-2:2011/AMD2:2018
3 Terms and definitions
3.8
intrinsic uncertainty of the measurand
Replace the existing source, modified by Amendment 1, with the following: “[CISPR 16-4-
1:2009, 3.1.6, modified – Deletion of notes]”
Add, after the existing definition 3.10, added by Amendment 1, the following new term and
definition as follows:
3.11
EUT volume
cylinder defined by EUT boundary diameter and height that fully encompasses all portions of
the actual EUT, including cable racks and 1,6 m of cable length (for 30 MHz to 1 GHz), or 0,3 m
of cable length (for 1 GHz and above)
NOTE 1 The test volume is one of several criteria limiting the EUT volume.
NOTE 2 The EUT volume has a diameter D (boundary diameter) and a height h.
4 Symbols and abbreviated terms
Add, to the existing introductory statement, the following new sentence as follows:
The following abbreviations are used in this technical report. Note that the symbol k is used for
four different quantities.
Add the following new lines to the existing list modified by Amendment 1:
FAR fully anechoic room
RC reverberation chamber
SCU standards compliance uncertainty
Replace the two existing lines K and k with the following:
k = 2π/λ, wave number (in this document, k is used in the electrical size ka, where a is the
EUT radius)
k(f) linear conversion factor
K(f) logarithmic conversion factor
k coverage factor
k Boltzmann’s constant
– 4 – CISPR TR 16-4-5:2006/AMD2:2021
 IEC 2021
5 Introduction
Replace the existing text with the following new text:
Over the years, several test methods and test set-ups for radiated disturbance measurement
have been described in basic standards. One particular combination of test method and test
set-up also having defined disturbance limits is the open area test site (OATS) method, which
has proven to be successful for the protection of radio services. Since the first edition of this
document, limits have been defined for other – alternative – test methods, e.g., fully anechoic
rooms and TEM waveguides, but not for reverberation chambers.
Each alternative method can be used to get measurement results related to disturbance from
an EUT. Although each method gives a disturbance level from an EUT, the different methods
might capture the EUT disturbance differently. For example, considering radiated disturbance
measurements, different methods may capture different EUT radiation pattern lobes, a different
number of lobes, or the test facility might alter the EUT radiation pattern producing a different
apparent disturbance level. Therefore the limits defined for the established test method cannot
be applied directly to the alternative test methods. Consequently, procedures are needed to
derive limits to be used for the results of alternative test methods.
The specification of such procedures considers the general goal of disturbance measurements,
which is to verify whether an EUT satisfies or violates certain compliance criteria. Past experi-
ence has shown that using the present system of established test methods and associated limits
yields a situation without many cases of interference due to conducted disturbance or radiated
disturbance. Applying an established test method with its associated limits will fulfill the protec-
tion requirement with a high probability. To preserve this situation, the most important require-
ment for the use of alternative test methods is the following:
– Use of an alternative test method in a normative standard shall provide the same protection
of radio services as the established test method.
This requirement can be met by developing procedures to derive disturbance limits for alterna-
tive test methods from the existing limits of the established test methods. Such procedures shall
relate the results from an alternative test method to those from an established test method.
Using the relations derived in this document, the limits of the relevant established test method
can be converted into limits for the alternative test method. The measured values of the alter-
native test method can then easily be evaluated against the converted limits. Such procedures
will provide a similar amount of protection, even though an alternative test method is used.
The limit conversion procedures consider the preceding goal of disturbance measurements.
The results of standard disturbance measurements can be considered as an approximation of
the interference potential of an EUT. Depending on the characteristics of an EUT (e.g., radiation
pattern characteristics for radiated disturbance test methods), and the test set-up, the measured
value deviates from the actual interference potential of the EUT. This deviation can be divided
into two parts: 1) a systematic deviation, which can be interpreted as a bias of the test method;
and 2) a random deviation depending on the characteristics of different EUTs, which can be
interpreted as an uncertainty of the test method. Each disturbance test method contains both
quantities, and consequently the established test method does too. In the following clauses, a
procedure based on these two quantities for comparing an alternative test method with the
established test method is described. To determine these quantities, the abstract term “inter-
ference potential” shall be expressed in terms of a physical quantity. For the purposes of this
document, this physical quantity is called the “reference quantity” X. Other details about com-
parison of test methods using a reference quantity can be found in [1] .
__________
Figures in square brackets refer to the Bibliography.

 IEC 2021
The significance of a reference quantity is under discussion (see Magdowski [16]). It is not used
in the derivation of limits for an alternative test method based on measurements (see Clause 7
of CISPR TR 16-4-5:2006/AMD1:2014), and in the derivation of limits for disturbance measure-
ments using a reverberation chamber (i.e. in this document).
Figure 1 – Overview of quantities to estimate for use in conversion procedure
Replace the existing figure with the following:

– 6 – CISPR TR 16-4-5:2006/AMD2:2021
 IEC 2021
Figure 2 – Overview of limit conversion procedure using estimated quantities
Replace the existing figure with the following:

Table 2 ‒ Overview of quantities and defining equations for conversion process
Add, at the bottom of the existing table, modified by Amendment 1, the following new rows:
E Maximum field strength of an EUT in µV/m measured using the ETM, (35)
max
i.e. at d = 10 m at an OATS/SAC from 80 MHz to 1 000 MHz,
and at d = 3 m at a FSOATS/FAR from 1 GHz to 18 GHz
P Power transmitted from an EUT in pW measured using the reverberation chamber (35)
T
a)
test method (ATM), and virtual power producing the field-strength maximum E
max
measured using the ETM
a)
The virtual power is the power generating E assuming the EUT directivity is estimated in this document.
max
 IEC 2021
Add, after the existing Clause 7, modified by Amendment 1, the following new Clause 8:
8 Derivation of limits for the use of reverberation chambers as ATM for
radiated disturbance measurements based on a statistical analysis of all
essential factors
8.1 Conversion factor
Measurement of radiated power from an EUT using the RC method is described in
IEC 61000-4-21 [22]. This clause attempts to provide rules to derive disturbance limits for the
radiated power measured using the RC test method based on existing limits for radiated field
strength measured using the ETM. Radiated field strength and radiated power of an EUT are
related via the EUT directivity, and EUT directivity depends on frequency and EUT volume.
Because the type of an EUT and its directivity are typically unknown for generic and product
standards, this clause uses a statistical estimate based on assumptions described by Krauthäu-
ser [19]. For comparison and easier understanding, the conversion factors using a short dipole
as a model are described in D.2.
With reference to Annex D, conversion factors
– from OATS/SAC to RC for 80 MHz to 1 000 MHz, and
– from FSOATS/FAR to RC for 1 GHz to 40 GHz.
are introduced.
NOTE The start frequency of 80 MHz is selected because IEC 61000-4-21:2011, Table B.2 [22] on field uniformity
requirements starts at 80 MHz. Because there are RCs with lower or higher lowest useable frequencies (LUFs),
80 MHz can be replaced by “LUF.” The highest frequency of 40 GHz is selected because that is under consideration
to be the highest frequency for all CISPR documents pending agreement by NCs.
The linear conversion factor k(f) is defined as in Equation (35)
kf( )= E P (35)
max T
where
E is the maximum field strength of an EUT in µV/m measured using the ETM;
max
P is the power transmitted from an EUT in pW measured using the RC test method
...