CISPR TR 16-4-4:2025
(Main)Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-4: The CISPR model for the calculation of limits for the protection of radio services
Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-4: The CISPR model for the calculation of limits for the protection of radio services
CISPR TR 16-4-4:2025 which is a Technical Report, establishes the CISPR model for the calculation of limits for the protection of radio services, based on data from the IEC Radio Services Database (RSD) and estimations of the input values for related probabilistic factors. This is part of the process of the derivation of disturbance limits in the radio frequency spectrum for use in publications containing emission requirements Application of this document leads to a frequency dependent limit result for a particular disturbance phenomenon and the considered product or product type establishing the technical basis in the CISPR limit specification procedure.
NOTE Non-technical parameters and terms that can be considered to influence a limit for inclusion in IEC publications are excluded from the modelling (see also Clause 4.6.5.3).
This third edition cancels and replaces the second edition published in 2007, Amendment 1:2017 and Amendment 2:2020. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) full revision of the limit calculation model;
b) the content on statistics of complaints was taken from this publication and published as separate document (CISPR TR 16-4-6);
c) application cases/rationales were separated from the model and will be handled in another document to be drafted.
General Information
Relations
Overview - What CISPR TR 16-4-4:2025 covers
CISPR TR 16-4-4:2025 is a Technical Report from IEC/CISPR that defines the CISPR model for the calculation of limits for the protection of radio services. It specifies a frequency‑dependent, model‑based process for deriving disturbance (emission) limits in the radio‑frequency spectrum using data from the IEC Radio Services Database (RSD) and estimated input values for related probabilistic factors. This third edition (2025) delivers a technical revision including a full update of the limit calculation model; statistical complaint content has been moved to CISPR TR 16-4-6, and application cases/rationales are separated into a future document. Non‑technical parameters that might influence limits are excluded from the CISPR modelling (see Clause 4.6.5.3).
Key technical topics and requirements
- CISPR limit calculation model - a revised, systematic framework to compute frequency‑dependent permissible interference field strengths for specified disturbance phenomena and product types.
- Use of RSD data - inputs and radio service planning data are taken from the IEC Radio Services Database to ensure consistency with real radio services.
- Systematic factors - deterministic elements that affect coupling between source and victim (e.g., coupling paths, receiver condition, standard test conditions).
- Probabilistic factors (S-factors) - quantified probabilities for real‑world variability (directional lobes, receiver orientation, coincidence of operation, obstacles, location coincidence, signal frequency coincidence, waveform significance, etc.).
- Coupling scenarios and path descriptions - models for radiation, conducted and wire‑line coupling (see Clause 4.2 and Annex D).
- Derivation and documentation - procedures to determine permissible field strength values, apply systematic/probabilistic factors and document the technical CISPR limit (Clauses 4.6–4.7).
- Mathematical foundations - informative annexes provide probability theory and modelling background (Annexes A–C, B for distribution modelling).
Practical applications - who uses this standard
- EMC engineers and test laboratories deriving or verifying emission limits for products and equipment.
- Standards developers and CISPR working groups creating or updating CISPR limits and emission publications.
- Spectrum managers, regulators and radio service planners assessing interference protection requirements.
- Product designers and compliance teams using model outputs to set design targets and mitigation measures.
- Certification bodies and conformity assessment entities referencing the technical basis for regulatory limits.
Related standards and resources
- CISPR family documents (other parts of CISPR 16) and the IEC Radio Services Database (RSD).
- CISPR TR 16-4-6 (statistics of complaints) - complementary to the probabilistic/statistical treatment.
- Obtained via the IEC Webstore and CISPR technical committee publications for full normative detail.
Keywords: CISPR TR 16-4-4:2025, CISPR model, calculation of limits, protection of radio services, IEC Radio Services Database, probabilistic factors, disturbance limits, RF spectrum, EMC.
Standards Content (Sample)
CISPR TR 16-4-4 ®
Edition 3.0 2025-10
TECHNICAL
REPORT
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE
Specification for radio disturbance and immunity measuring apparatus and
methods -
Part 4-4: The CISPR model for the calculation of limits for the protection of radio
services
ICS 33.100.10; 33.100.20 ISBN 978-2-8327-0778-4
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CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 The CISPR model for the calculation of limits . 7
4.1 General . 7
4.2 Basic disturbance coupling mechanisms . 8
4.2.1 Coupling scenarios. 8
4.2.2 Description of coupling paths . 8
4.3 Condition at the victim receiver . 9
4.4 Systematic factors . 9
4.4.1 General. 9
4.4.2 Factors conditional on the path between source and victim . 10
4.4.3 Factors conditional on standardised test . 10
4.5 Probabilistic factors . 11
4.5.1 General. 11
4.5.2 S probabilistic factor representing the effect of events that the major
Tx
lobe of the radiation is in the direction of the victim receiver . 12
4.5.3 S probabilistic factor representing the effect of directional receiving
Rx
aerials having maximum pick-up in the direction of the disturbing source . 12
4.5.4 S probabilistic factor representing the effect of events that the victim
stat
receiver is stationary . 12
4.5.5 S probabilistic factor representing the effect of equipment
freq
generating a disturbing signal on a critical frequency at which the radio
receiver is susceptible . 13
4.5.6 S probabilistic factor representing the effect of events that the
ml
disturbing signal is below E . 13
ir,corr
4.5.7 S probabilistic factor representing the effect of events that the type of
wf
disturbing signal being generated will produce a significant effect in the
receiving system . 14
4.5.8 S probabilistic factor representing the effect of coincident operation
time
of the disturbing source and the receiving system . 14
4.5.9 S probabilistic factor representing the effect of the disturbing source
loc
being within the distance at which interference is likely to occur . 15
4.5.10 S Probabilistic factor representing the effect of events that obstacles
att
(including buildings) provide attenuation . 16
4.6 Specification of a technical CISPR limit . 16
4.6.1 General. 16
4.6.2 Determination of the permissible interference field strength values . 17
4.6.3 Application of the systematic factors . 18
4.6.4 Application of the probabilistic factors . 18
4.6.5 Determination of a technical CISPR limit . 22
4.7 Documentation of the result . 23
Annex A (informative) Basic mathematical background . 24
A.1 General . 24
A.1.1 Overview . 24
A.1.2 Generation of EM disturbances . 24
A.1.3 Immunity from EM disturbances . 24
A.1.4 Planning a radio service . 24
A.2 Probability of interference . 25
A.2.1 General. 25
A.2.2 Derivation of probability of interference . 25
A.3 A mathematical basis for the calculation of CISPR limits . 27
A.3.1 General. 27
A.3.2 Generation of EM disturbances (source of disturbance) . 27
A.3.3 Immunity from EM disturbances (victim receiver) . 29
Annex B (informative) Mathematical basis for the calculation of the probability
distribution of the maximum disturbance amplitude at a receiver when surrounded by
uniformly distributed sources . 30
B.1 General . 30
B.2 Model and assumptions . 30
B.3 Probability distribution of received amplitude of a disturbance from an
arbitrary source . 31
B.4 Probability distribution of the maximum disturbance amplitude . 34
B.5 Comparison to Monte Carlo simulation results . 38
B.6 Application to some specific distributions . 39
B.6.1 General. 39
B.6.2 Binary discrete distribution . 39
B.6.3 Lognormal distribution . 40
B.6.4 Exponential distribution . 41
Annex C (informative) A simple approximation of the mean value and standard
deviation of the probabilistic factor of location coincidence . 44
Annex D (informative) Wire-line coupling. 46
D.1 Mains coupling using the mains decoupling factor . 46
D.2 Mains and telecommunication line coupling by radiation from a network . 47
D.2.1 General. 47
D.2.2 Example for the AM frequency range . 50
D.2.3 Guidance for field-strength measurements . 51
D.2.4 Example of a measurement result . 51
Annex E (informative) Cross reference for probabilistic factors . 55
Bibliography . 57
Figure 1 – Basic RFI model for source without radio module . 8
Figure 2 – Basic RFI model for source with radio module . 8
Figure 3 – tα against confidence level α . 20
Figure B.1 – Geometry of the interference model . 31
Figure B.2 – Integration ranges for conducting the integral (see Equation (B.8)) . 33
Figure B.3 – Probability densities of the maximum received disturbance amplitude . 39
Figure C.1 – Comparison of the exact and approximated values in the case of x = 1. 45
Figure D.1 – Example of conversion factors – field strength/common-mode voltage (in
dB) – at feed point, found in practice . 51
Figure D.2 – Example of conversion factors – field strength generated by differential-
mode voltage – at feed point, found in practice . 52
Figure D.3 – Example of conversion factors – field strength generated by differential-
mode voltage –outside buildings and electrical substations, found in practice . 53
Figure D.4 – Example of conversion factors – field strength generated by differential-
mode voltage – inside buildings, found in practice. 54
Table 1 – Coupling scenarios and relevant systematic/probabilistic factors . 17
Table E.1 – Cross reference of probabilistic factors in this document and CISPR
TR 16-4-4:2007, CISPR TR 16-4-4:2007/AMD1:2017 and CISPR
TR 16-4-4:2007/AMD2:2020 . 55
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Specification for radio disturbance and immunity measuring apparatus
and methods -
Part 4-4: The CISPR model for the calculation of limits for the protection
of radio services
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
CISPR TR 16-4-4 has been prepared by subcommittee H: Limits for the protection of radio
services, of IEC technical committee CISPR. It is a Technical report.
This third edition cancels and replaces the second edition published in 2007,
Amendment 1:2017 and Amendment 2:2020. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) full revision of the limit calculation model;
b) the content on statistics of complaints was taken from this publication and published as
separate document (CISPR TR 16-4-6);
c) application cases/rationales were separated from the model and will be handled in another
document to be drafted.
The text of this Technical Report is based on the following documents:
Draft Report on voting
CIS/H/524/DTR CIS/H/536A/RVDTR
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 Technical Report 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 http://www.iec.ch/standardsdev/publications.
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, or
– revised.
1 Scope
This Part of CISPR 16-4 establishes the CISPR model for the calculation of limits for the
protection of radio services, based on data from the IEC Radio Services Database (RSD) and
estimations of the input values for related probabilistic factors.
This is part of the process of the derivation of disturbance limits in the radio frequency spectrum
for use in publications containing emission requirements.
Application of this document leads to a frequency dependent limit result for a particular
disturbance phenomenon and the considered product or product type establishing the technical
basis in the CISPR limit specification procedure.
NOTE Non-technical parameters and terms that can be considered to influence a limit for inclusion in IEC
publications are excluded from the modelling (see also 4.6.5.3).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
protection distance
r
PD
distance between the source of a radiated disturbance and the victim receiver at the edge-of-
service area used for the derivation of a specific CISPR disturbance limit
Note 1 to entry: The edge-of-service area is defined by the minimum value of the wanted field strength of a radio
service or application derived from ITU-R specifications.
Note 2 to entry: This definition can vary in other publications, when conducted disturbances are concerned.
Note 3 to entry: Every limit has an associated protection distance; the protection distance can vary with frequency.
Note 4 to entry: The result of the calculation procedure based on a certain value of protection distance does not
ensure protection in all circumstances.
3.2
exclusion distance
r
E
lower bound of the distance from the victim receiver to the nearest disturbance source
Note 1 to entry: Within a distance shorter than this lower bound, emission from a source is not assumed or ignored
for the protection of a radio service.
Note 2 to entry: In special sensitive receiving situations (i.e. radio astronomy observations, military services) an
exclusion distance is defined by the administration.
3.3
worst-case limit
radio disturbance limit equal or equivalent to the field strength e /r , which is applied to the
w p
field strength emitted from a single disturbance source in the situation where there is minimum
decoupling to the victim receiver
Note 1 to entry: When the worst-case limit at the protection distance is converted to a limit value at another
measurement distance or converted to a limit value in terms of a different quantity in a deterministic way (e.g.,
magnetic field strength to equivalent electric field strength), such a new limit value is regarded as an equivalent
worst-case limit.
Note 2 to entry: Decoupling of disturbance between a source and the victim receiver is a random variable in general.
In the case of radiated disturbance, the words "minimum decoupling" means no attenuation other than by distance,
by setting all the probabilistic factors other than the location coincidence to be unity (or 0 dB). Minimum decoupling
to the receiver is often determined by distance attenuation at the protection distance unless an exclusion distance is
used or the purely conducted situation is observed.
Note 3 to entry: If the worst-case limit is applied to a conducted disturbance, the limit is given by the disturbance
voltage that generates disturbance equivalent to the field strength e /r at the victim receiver under the minimum
w p
decoupling condition. Note that the minimum decoupling of a conducted disturbance is usually determined based on
the statistics of measurement results in actual situations.
3.4
permissible interference field strength
E
ir
maximum field strength present at the victim receivers antenna which does not degrade the
reception of the radio receiver
Note 1 to entry: The terms "disturbance" and "interference" are used interchangeably within this document.
4 The CISPR model for the calculation of limits
4.1 General
A harmonized method of calculation is an important precondition for the efficient discussion of
CISPR limits by National Committees and the adoption of CISPR publications.
NOTE 1 The calculation procedure partly takes into account input parameters which are estimated by the user of
the TR. These parameters are described in 4.4 and 4.5.
The CISPR model considers all radio services and applications that have data in the IEC Radio
Services Database [1] . The technical approach taken here is to determine a limit for a given
frequency range to protect radio services and applications operating in that range.
NOTE 2 For those radio services and applications that have no data in the radio services database, the database
can be updated using the process given in CISPR TR 31 [2].
The worst-case levels can be moderated by a series of influencing factors that impact the
probability that interference will occur leading to a probabilistically modified limit value for the
emission at each frequency considered. In a final step of the calculation procedure based on
these frequency-dependent values, a continuous estimated CISPR model limit line is derived
which, however, can have steps at certain frequencies.
NOTE 3 The probabilistic modification process described above will always result in an increase in the probability
of interference. The intention is that the limit determined by this process will not produce a significant increase in the
actual number of interferences.
NOTE 4 See also 4.6.5.3 for subsequently dealing with this calculated limit line.
___________
Numbers in square brackets refer to the Bibliography.
4.2 Basic disturbance coupling mechanisms
4.2.1 Coupling scenarios
The model described in this document is based on electromagnetic disturbance phenomena
that can occur in the typical coupling scenarios depicted in Figure 1 and Figure 2.
NOTE Coupling mechanisms other than those shown in Figure 1 and Figure 2 can exist.
Figure 1 – Basic RFI model for source without radio module
Figure 2 – Basic RFI model for source with radio module
4.2.2 Description of coupling paths
4.2.2.1 Path A
This path covers the coupling between the EUT, via the air, via either ground or water or both
to the radio service or application. Path A covers both the far field and the near field of the
disturbance source. This path is in the scope of this document.
4.2.2.2 Path B
This path covers the coupling from the EUT via a conductor to the radio service or application
equipment. This only occurs when both are connected to each other via a conductor or network
of conductors. This path is in the scope of this document and further information is given in
Annex D.
NOTE 1 Cross talk between cables is also considered in this path.
NOTE 2 The cable representing the conducted path is not necessarily connected to the victim (path B in Figure 1
and Figure 2) as for example in telecommunication lines, where only the radiation coupling (path B ) exists.
4.2.2.3 Path B
This path covers the coupling from the EUT, via an external conductor to the air, ground via
either ground or water or both water and then to the radio service or application. Path B covers
both the far field and the near field of the conductor. This path is in the scope of this document.
NOTE 1 Examples of conductors are AC grid, DC grid, wired network cables, signal or control cables, metal trays
or bars, fibres with metal coating.
NOTE 2 Short conductors are typically covered by radiated tests (e.g. shorter than 3 m) while long conductors are
typically covered by conducted tests.
4.2.2.4 Path C
This path covers the coupling from a radio module in the EUT via the air, via ground or water
or both to the radio receiver's antenna. This coupling path is not in the scope of this document.
NOTE This coupling path is related to radio spectrum requirements.
4.2.2.5 Path D
This path covers the coupling from a radio module in the EUT via the air, via ground or water
or both to the non-radio part of the victim. This coupling path is not in the scope of this document.
NOTE This coupling path is related to immunity requirements.
4.3 Condition at the victim receiver
Considering the technical parameters for reliable reception of the radio service or application
to be protected, the permissible interference field strength E at the victim receiver can be
ir
determined by subtracting the necessary protection ratio R from the minimum wanted field
P
strength E needed for this radio reception (see Equation (1), all quantities expressed in
w
logarithmic units).
E = E – R
(1)
ir w P
NOTE 1 Values for the necessary parameters can be found in the IEC Radio Services database [1]; definition of
the terms is given in CISPR TR 31 [2].
In linear expressions this is
e = e /r
(2)
ir w p
NOTE 2 In this document, small letters are used for linear expressions and capital letters for logarithmic
expressions to remain consistent with the previous version of CISPR TR 16-4-4.
4.4 Systematic factors
4.4.1 General
Systematic factors are those factors that are not probabilistic as they are predetermined by
certain physical source specifics (including positioning restrictions) or by conditions
indispensable to be considered due to characteristics in the measurement in standardised
testing.
NOTE Systematic factors can be frequency dependent.
4.4.2 Factors conditional on the path between source and victim
4.4.2.1 Permanent screening factor
Obstacles (including buildings) can impact the level of the disturbance signal. Where these
obstacles are permanently present this can be considered by a systematic screening factor L .
b
EXAMPLE A situation where the factor is permanently present would be for a radio application that always uses an
antenna external to the building while the interference source is always installed inside a building having a certain
screening effect.
NOTE Where the obstacle is not always present, it is dealt with as probabilistic factor S (see 4.5.10).
att
4.4.2.2 Factor representing a guaranteed minimum distance between source and
victim
Some victims are always physically separated from disturbance sources by an exclusion
distance r . When an exclusion distance for a specific radio service is present, the protection
ex
distance takes the value from the exclusion distance, as noted in 4.5.9.
EXAMPLE Exclusion zones around radio astronomy reception sites.
4.4.3 Factors conditional on standardised test
4.4.3.1 Factor for measurement bandwidth
For broadband EMI the permissible interference field strength is based on a specific
standardised measurement bandwidth for the frequency range in question. If the radio service
or application evaluated uses the same bandwidths, as in some cases of broadcast radio, no
change is applicable. If the bandwidth of the victim radio service or application is different to
the measurement bandwidth, a correction is applied.
b
measurement
C 10×log
(3)
bw
b
victim
The appropriate measurement bandwidth (reference bandwidth) can be found in CISPR 16-1-1
[3].
NOTE If the emissions are evenly spread over frequency within both the measurement bandwidth and the victim
bandwidth, they are considered broadband in this subclause.
In other cases, the correction is 0 dB.
4.4.3.2 Factor for conversion from the protection distance to the measurement
distance
If the product standard for which the limit is derived defines a measurement distance d that
deviates from the protection distance r it is important to introduce an appropriate conversion
PD
factor (L ). This conversion factor can be determined using
L = x × 20 × (log(r /d))
(4)
0 PD
where x is the appropriate propagation factor, which is 1 in free-space propagation in the far
field and somewhat higher (1 to 1,5) for non-free-space propagation.
=
Under near-field conditions, the propagation coefficient x is more complex and dependent on
the magnetic or electric component. Other models can be used, further information is available
in the P series of recommendations from the ITU-R.
For this reason, it is much easier to develop a model for remote coupling conditions than for
close coupling situations and for conduction coupling paths. Such a model is applicable to
derive emission limits for a general interference environment.
4.4.3.3 Factor for conversion into another test measurand (i.e. coupling factor)
If the measurand of the reception parameter happen to be different from the test measurand, a
suitable conversion factor C is determined that reflects the coupling characteristics underlying
the transfer of the disturbance signal.
EXAMPLE In case of coupling mechanism B (combination of the conduction and radiation coupling path) the limit
to be derived is converted to the measuring for conducted disturbance although the conditions on the victim's side
will be given as field strength. In that case the coupling characteristics underlying the transfer from the conducted to
a radiated disturbance are combined with the characteristics of the measurement device (for example the termination
impedance of the AAN) and this combination are considered using a suitable coupling factor.
4.5 Probabilistic factors
4.5.1 General
In 4.4 the maximum permissible disturbance level considering systematic factors has been
described. It represents a maximum permissible field strength level that is calculated to provide
full protection of radio reception against interference from the equipment for which this level is
being derived.
Besides the described systematic factors (4.4) in the derivation of a limit, various probabilistic
factors can be considered either by means of probabilities of coincidence P , or by the mean
i
values µ (see 4.6.4) and their corresponding standard deviations σ .
Pi Pi
The probabilistic factors as described in this document are in many cases equivalent or similar
to those used in the previous editions of this document. A cross-reference table is given in
Annex E (Table E.1).
NOTE 1 In the preceding version of CISPR TR 16-4-4 the term "probability factor" was used. However, in the use
of the model the term "probability factor" was interpreted as either "statistical" or "probabilistic" and caused repeated
misunderstanding. To clearly differentiate between these aspects the name of the factors was changed from
"probability" to "probabilistic". This is intended to stress the forecasting character of the introduced factors, as by
definition probability deals with predicting the likelihood of future events, while statistics encompasses the analysis
of the frequency of past events.
NOTE 2 As far as this document is concerned, coincidence incorporates both factors, those that occur by chance
and also those that occur simultaneously because they are related.
NOTE 3 The basic mathematical background on dealing with probabilities is given in CCIR Report 829. The essence
of the report is included in Annex A.
Some of these can follow a probability distribution that is binary in their nature (either emission
with a probability P or no emission with 1-P depending on the coincidence of time, frequency,
i i
etc.) and hence will be expressed by the probability of coincidence P . And other factors can
i
have a continuous distribution and be represented by the pair of statistical mean value µ and
Pi
standard deviations σ in decibels.
Pi
The applicable probabilistic factors have each to be determined for the situation being analysed,
the factors frequently used are described in the following clauses.
For each of the probabilistic factors (or in some cases a group of combined probabilistic factors)
the known probability function or a mathematical approximation can be used to determine the
mean and standard deviation (µ , σ ) from the probability density function (see Annex B).
Pn Pn
The estimation of the appropriate values for individual factors can be complex and
determination of a particular value for the general case is challenging. When the value of a
probabilistic factor cannot be appropriately assessed the value of 1 can be used.
4.5.2 S probabilistic factor representing the effect of events that the major lobe of
Tx
the radiation is in the direction of the victim receiver
This factor represents the effect of the probabilistic events that the antenna of the radio
reception installation will be exposed to maximum radiation from the disturbance source
emanating in direction of the major lobe in the disturbance source's radiation pattern. When it
can be assumed, the direction of maximum radiation is random relative to the direction of victim
receiver, the disturbance field strength at the victim receiver can be regarded as a probabilistic
factor. If the radiation pattern has a major lobe with a beam width θ , this probabilistic factor is
e
expressed by the probability of coincidence P that is given by θ /2π. If radiation pattern does
Tx e
not have a clear major lobe but has a continuous variation as a function of azimuth angle, the
probabilistic factor is represented by the mean value and standard deviation (µ , σ ) of the
PTx PTx
disturbance strength that is normalized by its peak value. Since the normalized field strength
takes the maximum value of zero dB or negative values otherwise, the µ (positive value) is
PTx
given by the sign inversion of the mean value of the normalized field strength.
NOTE For high frequencies in which considerable antenna gains are expected the radiation pattern is independent
of the distance r ( > protection distance) from the source as the minimum distance from the source to the receiver
i
is in the far field region of the source. For low frequencies, this could not be the case which could make the
applicability of this factor much more complex and is often to be set to unity, especially in indoor receiving situations.
4.5.3 S probabilistic factor representing the effect of directional receiving aerials
Rx
having maximum pick-up in the direction of the disturbing source
This factor describes the effect of the probabilistic events that the axis of the major lobe of the
radio reception installation's directional antenna points to the nearby location of the disturbance
source. This probabilistic factor can be expressed either by the probability of coincidence P
Rx
or the mean value and standard deviation (µ , σ ) similarly to the case of P .
Rx Rx Tx
A directive receiver antenna having a major lobe acts as a spatial filter to effectively reduce the
number of sources that have interference potential.
NOTE For high frequencies in which considerable antenna gains are expected the distance from the receiver
antenna to the nearest source is in the far field region of the receiving antenna. For low frequencies this could not
be the case which could make the applicability of this factor much more complex and is often to be set to unity,
especially in indoor receiving situations.
4.5.4 S probabilistic factor representing the effect of events that the victim
stat
receiver is stationary
S describes the probability that a mobile victim receiver is in a fixed position.
stat
When sources exist only in a limited area, mobile radio reception could reduce the probability
of interference. However, in a situation that multiple disturbance sources are distributed,
mobility of the receiver does not reduce the probability of interference, and hence P is unity.
stat
The mobility of the receiver transforms the variation in the disturbance strength in the space
domain to the variation in time. If a receiver is randomly moved around in an area within which
large number of sources are randomly distributed, the probabilistic properties of the time
variation in the received disturbance strength would be represented with the probabilistic factors
that are respectively nearly same as those for stationary receivers.
EXAMPLE The receiving antenna could be moving, movable or stationary. A fixed antenna could include a roof-top
TV receiving antenna, a movable antenna could be in a portable equipment, a moving antenna could be in a vehicle,
in which case the interference will be only temporary in nature.
4.5.5 S probabilistic factor representing the effect of equipment generating a
freq
disturbing signal on a critical frequency at which the radio receiver is
susceptible
This factor describes the effect of the probabilistic events when the disturbance source emits a
signal on a frequency on which the radio is susceptible. This factor is expressed either by the
in a case of binary distribution of disturbance strength
probability of frequency coincidence P
freq
(i.e., no emission in the signal bandwidth with the probability of 1-P or maximum emission is
freq
found with the probability P ), or by the mean value and standard deviation (µ , σ ) in a
freq freq freq
case that disturbance always exists within the signal bandwidth but has frequency-dependent
variations in the power. This factor is carefully evaluated with the consideration of the following
points:
a) Whether the frequency of the wanted signal is preassigned (fixed) or dynamically assigned
(varying in time).
b) Whether the disturbance spectrum at the frequency band of interest is dominated by discrete
(line) spectrum or by continuous spectrum. Note that the observed spectral characteristics
of a disturbance depend on the resolution bandwidth of the measuring receiver. It is
desirable for the evaluation of this factor that the disturbance spectrum is measured with a
resolution bandwidth that is in the same order of the signal bandwidth (or the sub-channel
bandwidth for a signal using a multicarrier modulation scheme), if possible.
c) When discrete component is dominating the disturbance spectrum, it is important to estimate
the frequency variation range of the major spectral peaks depending on the individual
products. For example, the frequency of clock harmonics of many digital devices is not
strictly the same, nor completely random, but distributed within a certain frequency range.
It is important that any calculations consider the variations in the frequencies used over all
possible products.
NOTE It is essential to consider that the distribution of disturbance spectrum across a frequency band is not
necessarily random and for some products interference will occur at a much higher probability on a limited number
of frequencies. Consider setting this probability to 1 to protect these frequencies.
If the wanted signal band is fixed and the frequency variation of the major peaks in the
disturbance spectrum is estimated to be always within the signal band width, then the
interference is deterministic, i.e., probability of coincidence P = 1. when either the signal
freq
frequency or the frequency of the disturbance spectra or both has variation that is wider than
the signal bandwidth, the probabilistic factor is expressed by the probability of frequency
coincidence P , which will be less than unity. When the disturbance spectrum is dominated
freq
by a continuous spectrum, disturbance power existing within the signal bandwidth will be a
continuous random variable, and the probabilistic factor is expressed by the mean and standard
deviation (µ , σ ) of the disturbance level relative to its peak value in decibels.
freq freq
4.5.6 S probabilistic factor representing the effect of events that the disturbing
ml
signal is below E
ir,corr
S describes the probability that the interference source emits a signal below the level required
ml
to protect radio services (abbreviation "ml" stands for margin to the limit). In many cases
equipment is designed with a margin to the limit.
NOTE Usually, disturbances from a certain source do not just meet the limits but have a certain margin to them.
This factor counts for the estimated average of the minimum margin of the disturbance to the limit.
As this factor can be difficult to be calculated objectively, factors like the various manufacturer
specifications are considered, it is set to unity as long as no evident derivation can be made. If
a derivation is made, documentation of the applied parameters and the procedure applies. In
any case S cannot exceed a value of 2 dB maximum.
ml
4.5.7 S probabilistic factor representing the
...
Frequently Asked Questions
CISPR TR 16-4-4:2025 is a technical report published by the International Electrotechnical Commission (IEC). Its full title is "Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-4: The CISPR model for the calculation of limits for the protection of radio services". This standard covers: CISPR TR 16-4-4:2025 which is a Technical Report, establishes the CISPR model for the calculation of limits for the protection of radio services, based on data from the IEC Radio Services Database (RSD) and estimations of the input values for related probabilistic factors. This is part of the process of the derivation of disturbance limits in the radio frequency spectrum for use in publications containing emission requirements Application of this document leads to a frequency dependent limit result for a particular disturbance phenomenon and the considered product or product type establishing the technical basis in the CISPR limit specification procedure. NOTE Non-technical parameters and terms that can be considered to influence a limit for inclusion in IEC publications are excluded from the modelling (see also Clause 4.6.5.3). This third edition cancels and replaces the second edition published in 2007, Amendment 1:2017 and Amendment 2:2020. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) full revision of the limit calculation model; b) the content on statistics of complaints was taken from this publication and published as separate document (CISPR TR 16-4-6); c) application cases/rationales were separated from the model and will be handled in another document to be drafted.
CISPR TR 16-4-4:2025 which is a Technical Report, establishes the CISPR model for the calculation of limits for the protection of radio services, based on data from the IEC Radio Services Database (RSD) and estimations of the input values for related probabilistic factors. This is part of the process of the derivation of disturbance limits in the radio frequency spectrum for use in publications containing emission requirements Application of this document leads to a frequency dependent limit result for a particular disturbance phenomenon and the considered product or product type establishing the technical basis in the CISPR limit specification procedure. NOTE Non-technical parameters and terms that can be considered to influence a limit for inclusion in IEC publications are excluded from the modelling (see also Clause 4.6.5.3). This third edition cancels and replaces the second edition published in 2007, Amendment 1:2017 and Amendment 2:2020. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) full revision of the limit calculation model; b) the content on statistics of complaints was taken from this publication and published as separate document (CISPR TR 16-4-6); c) application cases/rationales were separated from the model and will be handled in another document to be drafted.
CISPR TR 16-4-4:2025 is classified under the following ICS (International Classification for Standards) categories: 33.100.10 - Emission; 33.100.20 - Immunity. The ICS classification helps identify the subject area and facilitates finding related standards.
CISPR TR 16-4-4:2025 has the following relationships with other standards: It is inter standard links to CISPR TR 16-4-4:2007/AMD1:2017, CISPR TR 16-4-4:2007/AMD2:2020, CISPR TR 16-4-4:2007. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase CISPR TR 16-4-4:2025 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.
CISPR TR 16-4-4:2025は、無線サービスの保護のための限界計算を行うCISPRモデルを確立する技術報告書です。この標準は、IEC無線サービスデータベース（RSD）からのデータと関連する確率的要因の入力値推定に基づいています。無線周波数スペクトルにおける干渉限界の導出プロセスの一部として、この文書の適用は、特定の干渉現象および考慮される製品または製品タイプに対して周波数依存の限界結果をもたらします。これにより、CISPR限界仕様手順における技術的基盤が確立されます。 この第三版は、2007年に出版された第二版および修正第1版（2017年）および修正第2版（2020年）を取消し、置き換えるものであり、技術的改訂が行われています。本版においては、限界計算モデルの全面的な改訂や、苦情の統計に関する内容がこの出版物から分離されて別文書（CISPR TR 16-4-6）として発表されるなど、過去の版との重要な技術的変更があります。また、適用ケースや根拠がモデルから分離され、別途作成される文書で扱われることになっています。 このCISPR TR 16-4-4:2025は、無線通信の防護に関する限界の計算を定義するものであり、無線サービスの健全性を確保する上で極めて重要です。そのため、無線サービスの保護に関連する企業や研究機関にとって、今後の技術開発や製品設計に必須の基準となるでしょう。また、非技術的なパラメータや用語がモデルから除外されている点も注目に値します。このように、CISPR TR 16-4-4:2025は、無線干渉の管理についての信頼性の高い指針を提供し、関連する利害関係者にとって非常に有益です。
CISPR TR 16-4-4:2025는 무선 서비스 보호를 위한 한계 계산을 위한 CISPR 모델을 수립한 기술 보고서로, IEC 무선 서비스 데이터베이스(RSD)의 데이터를 기반으로 관련 확률적 요인에 대한 입력 값의 추정을 포함합니다. 이 표준은 무선 주파수 스펙트럼에서 발생하는 방해 한도를 도출하는 과정의 일환으로, emission 요구 사항을 포함한 출판물에서 사용됩니다. 이 문서의 적용은 특정 방해 현상과 고려된 제품 또는 제품 유형에 대해 주파수 종속적인 한계 결과를 도출하게 하여 CISPR 한계 명세 절차의 기술적 기초를 확립합니다. 비기술적 매개 변수 및 용어는 IEC 출판물에 포함될 한계에 영향을 미칠 수 있다고 고려되지만, 모델링에서는 제외됩니다(제4.6.5.3항 참조). 이 제3판은 2007년에 발행된 제2판, 개정판 1:2017 및 개정판 2:2020을 취소 및 대체하며, 기술적 revision이 이루어진 점이 특징입니다. 이전 판과 관련하여 다음과 같은 중요한 기술적 변경사항이 포함되어 있습니다: a) 한계 계산 모델의 완전한 개정; b) 불만 통계에 대한 내용이 이 출판물에서 추출되어 별도의 문서(CISPR TR 16-4-6)로 발행되었습니다; c) 적용 사례 및 합리성이 모델에서 분리되어 별도의 문서로 작성될 예정입니다. CISPR TR 16-4-4:2025는 무선 서비스를 보호하기 위한 한계 산출에 대한 표준화된 접근 방식을 제공하며, 관련 분야의 연구와 개발에 중요한 기초 자료로서의 가치를 지니고 있습니다. 이 표준은 방해 한도를 정확하고 효과적으로 설정하기 위해 최신 기술적 변화를 반영하고 있어, 무선 주파수 스펙트럼의 관리 및 규제에 있어 필수적인 참고자료로 활용될 수 있습니다.
CISPR TR 16-4-4:2025 establishes a comprehensive framework for the calculation of limits that protect radio services from disturbances, making it an essential document for professionals in the field of electromagnetic compatibility (EMC). The extensive use of data from the IEC Radio Services Database underpins the robustness of the model presented, ensuring that it is grounded in relevant and current information. One of the significant strengths of this standard is its focus on probabilistic factors that influence radio disturbance limits. By considering various input values, the CISPR model allows for a nuanced and accurate assessment of disturbance phenomena, tailored to specific product types. This structured approach not only aids in compliance with emission requirements but also enhances overall radio service resilience against interference. The relevance of CISPR TR 16-4-4:2025 is particularly evident in its thorough revision of the limit calculation model. The updates reflect advancements in technology and an improved understanding of the electromagnetic environment, allowing stakeholders to align their products with contemporary standards. The separation of application cases and rationales into future documentation ensures that the model remains focused and clear, streamlining the standard while enhancing its applicability. Furthermore, the exclusion of non-technical parameters from the modeling process emphasizes the document's commitment to precision and clarity. This focus on technical validity enhances its credibility and makes it a valuable resource for both manufacturers and regulatory bodies committed to maintaining the integrity of radio services. In conclusion, CISPR TR 16-4-4:2025 serves as a critical guideline for establishing disturbance limits in the radio frequency spectrum, making it a pivotal reference for ensuring the protection of radio services in an increasingly complex electromagnetic landscape. The standard’s systematic approach and significant technical revisions underscore its importance in promoting compliance and compatibility in modern radio communications.
CISPR TR 16-4-4:2025 constitue un document technique essentiel pour l'établissement de limites de protection des services radio. Son champ d'application se concentre sur la modélisation des perturbations radioélectriques, proposant un modèle CISPR pour le calcul des limites en se basant sur les données de la base de données des services radio de l'IEC. Cette approche repose sur des estimations de valeurs d'entrée pour des facteurs probabilistes connexes, ce qui permet d'établir des limites de perturbation adaptées au spectre des radiofréquences. Parmi les points forts de ce rapport, on note la révision complète du modèle de calcul des limites, ce qui témoigne d'une réponse proactive aux évolutions technologiques et aux besoins actuels. La séparation des cas d'application et des justifications du modèle vers un document distinct souligne l'intention d'accroître la clarté et la praticité du rapport, facilitant ainsi son utilisation par les professionnels du domaine. En outre, l'exclusion des paramètres et termes non techniques de la modélisation contribue à simplifier l'interprétation des résultats, rendant ce document encore plus pertinent pour les praticiens et chercheurs. La troisième édition remplace efficacement les précédentes versions, intégrant des modifications techniques significatives et assurant une mise à jour nécessaire de l'approche. La pertinence de CISPR TR 16-4-4:2025 est indiscutable pour les normes de l'IEC concernant les exigences d'émission. En fournissant une base technique solide pour le cadre de spécification des limites CISPR, ce rapport devient un outil incontournable pour garantir la conformité des produits face aux exigences de perturbation radioélectrique, assurant ainsi la protection des services radio dans un environnement toujours plus connectée.
Die Norm CISPR TR 16-4-4:2025 bietet eine umfassende und präzise Grundlage für die Berechnung von Grenzwerten zum Schutz von Funkdiensten. Sie basiert auf umfangreichen Daten aus der IEC Radio Services Database (RSD) und integriert Schätzungen von Eingabewerten für verwandte probabilistische Faktoren. Dieser technische Bericht ist von großer Relevanz für die Ableitung von Störgrenzen im Funkfrequenzspektrum und dient als wesentliche Grundlage in der CISPR-Grenzwert- Spezifikationsprozedur. Ein herausragendes Merkmal dieser Norm ist die vollständige Überarbeitung des Grenzwertberechnungsmodells, das die Anwendungsmöglichkeiten und genauen Anforderungen an die Schutzmaßnahmen gegen Funkstörungen verbessert. Durch die Fokussierung auf frequenzabhängige Grenzwerte für spezifische Störphänomene und das jeweilige Produkt oder Produkttyp, bietet die Norm ein präzises und anpassbares Instrument zur Sicherstellung der Einhaltung der Emissionsanforderungen in relevanten Publikationen. Die dritte Ausgabe ersetzt die vorherige Ausgabe von 2007 sowie die späteren Amendements und stellt eine maßgebliche technische Überarbeitung dar. Insbesondere die Trennung der Anwendungsszenarien von dem Modell und deren künftige Behandlung in einem separaten Dokument tragen dazu bei, die Klarheit und Benutzerfreundlichkeit des Inhalts zu verbessern. Indem die Norm nicht technische Parameter und Begriffe, die die Grenzwertberechnung beeinflussen könnten, aus dem Modell ausschließt, wird sichergestellt, dass der Fokus auf den relevanten technischen Aspekten bleibt. Insgesamt besticht die CISPR TR 16-4-4:2025 durch ihren strukturierten und klaren Ansatz zur Gewährleistung der Integrität von Funkdiensten, unterstützt durch ein robustes Fundament an Daten und eine präzise Methodik. Diese Norm ist entscheidend für alle, die sich mit der Messung von Funkstörungen und Immunität beschäftigen, und trägt maßgeblich zur Weiterentwicklung der Standards in diesem Bereich bei.
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