SIST EN 61000-4-15:2001
(Main)Electromagnetic compatibility (EMC) - Part 4-15: Testing and measurement techniques - Flickermeter - Functional and design specifications
Electromagnetic compatibility (EMC) - Part 4-15: Testing and measurement techniques - Flickermeter - Functional and design specifications
Gives a functional and design specification for flicker measuring apparatus intended to indicate the correct flicker perception level for all practical voltage fluctuation waveforms. Information is presented to enable such an instrument to be constructed. A method is given for the evaluation of flicker severity on the basis of the output of flickermeters complying with this standard.
Elektromagnetische Verträglichkeit (EMV) - Teil 4-15: Prüf- und Messverfahren - Flickermeter - Funktionsbeschreibung und Auslegungsspezifikation
Compatibilité électromagnétique (CEM) - Partie 4-15: Techniques d'essai et de mesure - Flickermètre - Spécifications fonctionnelles et de conception
Traite des spécifications fonctionnelles et de conception d'un appareil mesurant le flicker, destiné à indiquer le niveau correct de perception du flicker du flux lumineux (le flicker) pour toutes les formes d'onde de fluctuation de la tension rencontrées dans la pratique. On y présente des informations permettant de construire un tel instrument. Une méthode d'évaluation de la sévérité du flicker est fournie à partir des résultats obtenus avec des flickermètres en conformité avec cette norme.
Elektromagnetna združljivost (EMC) - 4-15. del: Preskusne in merilne tehnike - Flikermeter - Specifikacije funkcij in zasnove (IEC 61000-4-15:1997)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61000-4-15:2001
01-marec-2001
1DGRPHãþD
SIST EN 60868:2001
SIST EN 60868-0:2001
Elektromagnetna združljivost (EMC) - 4-15. del: Preskusne in merilne tehnike -
Flikermeter - Specifikacije funkcij in zasnove (IEC 61000-4-15:1997)
Electromagnetic compatibility (EMC) - Part 4-15: Testing and measurement techniques -
Flickermeter - Functional and design specifications
Elektromagnetische Verträglichkeit (EMV) - Teil 4-15: Prüf- und Messverfahren -
Flickermeter - Funktionsbeschreibung und Auslegungsspezifikation
Compatibilité électromagnétique (CEM) - Partie 4-15: Techniques d'essai et de mesure -
Flickermètre - Spécifications fonctionnelles et de conception
Ta slovenski standard je istoveten z: EN 61000-4-15:1998
ICS:
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
SIST EN 61000-4-15:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 61000-4-15:2001
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SIST EN 61000-4-15:2001
NORME
CEI
INTERNATIONALE
IEC
61000-4-15
INTERNATIONAL
Première édition
STANDARD
First edition
1997-11
PUBLICATION FONDAMENTALE EN CEM
BASIC EMC PUBLICATION
Compatibilité électromagnétique (CEM) –
Partie 4:
Techniques d’essai et de mesure –
Section 15: Flickermètre – Spécifications
fonctionnelles et de conception
Electromagnetic compatibility (EMC) –
Part 4:
Testing and measurement techniques –
Section 15: Flickermeter – Functional and
design specifications
IEC 1997 Droits de reproduction réservés Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique, y compris la photo- including photocopying and microfilm, without permission in
copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http: //www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
PRICE CODE S
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue
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SIST EN 61000-4-15:2001
61000-4-15 © IEC:1997 – 3 –
CONTENTS
Page
FOREWORD . 5
INTRODUCTION . 7
Clause
1 Scope and object . 9
2 Normative references. 9
3 Description of the instrument. 11
3.1 General . 11
3.2 Block 1 – Input voltage adaptor and calibration checking circuit . 13
3.3 Block 2 – Square law demodulator . 13
3.4 Blocks 3 and 4 – Weighting filters, squaring and smoothing. 13
3.5 Block 5 – On-line statistical analysis. 13
3.6 Outputs. 15
4 Specification . 17
4.1 Analogue response . 17
4.2 Input transformer . 19
4.3 Voltage adaptor . 21
4.4 Internal generator for calibration checking. 21
4.5 Squaring demodulator . 23
4.6 Weighting filters. 23
4.7 Overall response from input to output of block 3 . 23
4.8 Range selector. 23
4.9 Squaring multiplier and sliding mean filter . 25
4.10 General statistical analysis procedure . 25
4.11 Temperature and humidity operating range of the instrument. 27
5 Performance testing. 27
6 Type test and calibration specifications . 29
6.1 General . 29
6.2 Insulation and electromagnetic compatibility tests (provisional). 29
6.3 Climatic tests . 31
Figures
1 Functional diagram of UIE flickermeter. 37
2 Basic illustration of the time-at-level method. 39
Annex A – Techniques to improve accuracy of flicker evaluation . 41
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
––––––––
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4: Testing and measurement techniques –
Section 15: Flickermeter – Functional and
design specifications
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61000-4-15 has been prepared by subcommittee 77A: Low-
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
It forms section 15 of part 4 of the IEC 61000 series. It has the status of a basic EMC
publication in accordance with IEC guide 107.
The text of this standard is based on the following documents:
FDIS Report on voting
77A/180/FDIS 77A/190/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.
Annex A forms an integral part of this standard.
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INTRODUCTION
IEC 61000-4 is a part of the IEC 61000 series, according to the following structure:
Part 1: General
General consideration (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of the product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 6: Generic standards
Part 9: Miscellaneous
Each part is further subdivided into sections which are to be published either as International
Standards or as technical reports.
These sections of IEC 61000-4 will be published in chronological order and numbered
accordingly.
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ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4: Testing and measurement techniques –
Section 15: Flickermeter – Functional and
design specifications
1 Scope and object
This section of IEC 61000-4 gives a functional and design specification for flicker measuring
apparatus intended to indicate the correct flicker perception level for all practical voltage
fluctuation waveforms. Information is presented to enable such an instrument to be
constructed. A method is given for the evaluation of flicker severity on the basis of the output of
flickermeters complying with this standard.
This section is based on specifications prepared by the “Disturbances” working group of the
International Union for Electroheat (UIE) and published in 1992. Consequently the flickermeter
specifications in this section relate only to measurements of 230 V, 50 Hz inputs; specifications
for other voltages and other frequencies are under consideration.
The object of this section is to provide basic information for the design and the instrumentation
of an analogue or digital flicker measuring apparatus. It does not give tolerance limit values of
flicker severity.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this section of IEC 61000-4. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties to
agreements based on this section of IEC 61000-4 are encouraged to investigate the possibility
of applying the most recent edition of the normative documents indicated below. Members of
IEC and ISO maintain registers of currently valid International Standards.
IEC 60068-2-1:1990, Environmental testing – Part 2: Tests – Tests A: Cold
IEC 60068-2-2:1974, Environmental testing – Part 2: Tests – Tests B: Dry heat
IEC 60068-2-3:1969, Environmental testing – Part 2: Tests – Test Ca: Damp heat, steady state
IEC 60068-2-14:1984, Environmental testing – Part 2: Tests – Test N: Change of temperature
IEC 61000-3-3:1994, Electromagnetic compatibility (EMC) – Part 3: Limits – Section 3:
Limitation of voltage fluctuations and flicker in low-voltage supply systems for equipment with
rated current ≤ 16 A
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IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 2: Electrostatic discharge immunity test
IEC 61000-4-3:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 3: Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 4: Electrical fast transient/burst immunity test
IEC 61000-4-5:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 5: Surge immunity test
IEC 61000-4-6:1996, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 6: Immunity to conducted disturbances induced by radio-frequency fields
IEC 61000-4-8:1993, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 8: Power frequency magnetic field immunity test
IEC 61000-4-9:1993, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 9: Pulse magnetic field immunity test
IEC 61000-4-11:1994, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 11: Voltage dips, short interruptions and voltage variations immunity tests
IEC 61000-4-12:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 12: Oscillatory waves immunity test
IEC 61010-1:1990, Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 1: General requirements
IEC 61326-1:1997, Electrical equipment for measurement, control and laboratory use –
Electromagnetic compatibility (EMC) requirements – Part 1: General requirements
IEC 61326-10, Electrical equipment for measurement, control and laboratory use –
Electromagnetic compatibility (EMC) requirements – Part 10: Particular requirements for
*
equipment used in industrial locations
3 Description of the instrument
3.1 General
The description given below is based on an analogue implementation.
The flickermeter architecture is described by the block diagram of figure 1, and can be divided
into two parts, each performing one of the following tasks:
– simulation of the response of the lamp-eye-brain chain;
– on-line statistical analysis of the flicker signal and presentation of the results.
The first task is performed by blocks 2, 3 and 4 of figure 1, while the second task is
accomplished by block 5.
––––––––
*
To be published.
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3.2 Block 1 – Input voltage adaptor and calibration checking circuit
This block contains a signal generator to check the calibration of the flickermeter on site and a
voltage adapting circuit that scales the mean r.m.s. value of the input mains frequency voltage
down to an internal reference level. In this way flicker measurements can be made
independently of the actual input carrier voltage level and expressed as a per cent ratio. Taps
on the input transformer establish suitable input voltage ranges to keep the input signal to the
voltage adaptor within its permissible range.
NOTE – In digital instruments the voltage adaption may be performed by multiplying the instantaneous input voltage
by 230 V divided by the actual input voltage averaged over 60 s.
3.3 Block 2 – Square law demodulator
The purpose of this block is to recover the voltage fluctuation by squaring the input voltage
scaled to the reference level, thus simulating the behaviour of a lamp.
3.4 Blocks 3 and 4 – Weighting filters, squaring and smoothing
Block 3 is composed of a cascade of two filters and a measuring range selector, which can
precede or follow the selective filter circuit.
The first filter eliminates the d.c. and double mains frequency ripple components of the
demodulator output.
The second filter is a weighting filter block that simulates the frequency response to sinusoidal
voltage fluctuations of a coiled filament gas-filled lamp (60 W – 230 V) combined with the
human visual system. The response function is based on the perceptibility threshold found at
each frequency by 50 % of the persons tested.
NOTE – A reference filament lamp for 100-130 V systems would have a different frequency response and would
require a corresponding adjustment of the weighting filter. The characteristics of discharge lamps are totally
different, and substantial modifications to this standard would be necessary if they were taken into account.
Block 4 is composed of a squaring multiplier and a first order low-pass filter. The human flicker
sensation via lamp, eye and brain is simulated by the combined non-linear response of blocks
2, 3 and 4.
Block 3 alone is based on the borderline perceptibility curve for sinusoidal voltage fluctuations;
the correct weighting of non-sinusoidal and stochastic fluctuations is achieved by an
appropriate choice of the complex transfer function for blocks 3 and 4. Accordingly the correct
performance of the model has also been checked with periodic rectangular signals as well as
with transient signals.
The output of block 4 represents the instantaneous flicker sensation.
3.5 Block 5 – On-line statistical analysis
Block 5 incorporates a microprocessor that performs an on-line analysis of the flicker level,
thus allowing direct calculation of significant evaluation parameters.
A suitable interface allows data presentation and recording. The use of this block is related to
methods of deriving measurements of flicker severity by statistical analysis. The statistical
analysis, performed on line by block 5 shall be made by subdividing the amplitude of the flicker
level signal into a suitable number of classes. The flicker level signal is sampled at a constant
rate.
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Every time that the appropriate value occurs, the counter of the corresponding class is
incremented by one. In this way, the frequency distribution function of the input values is
obtained. By choosing a scanning frequency of at least twice the maximum flicker frequency,
the final result at the end of the measuring interval represents the distribution of flicker level
duration in each class. Adding the content of the counters of all classes and expressing the
count of each class relative to the total gives the probability density function of the flicker
levels.
From this function is obtained the cumulative probability function used in the time-at-level
statistical method. Figure 2 schematically represents the statistical analysis method, limited for
simplicity of presentation to 10 classes.
From the cumulative probability function, significant statistical values can be obtained such as
mean, standard deviation, flicker level being exceeded for a given percentage of time or,
alternatively, the percentage of time that an assigned flicker level has been exceeded.
The observation period is defined by two adjustable time intervals: T and T .
short long
The long interval defines the total observation time and is always a multiple of the short
interval:
(T = n × T )
long short
For on-line processing, immediately after conclusion of each short time interval, the statistical
analysis of the next interval is started and the results for the expired interval are made
available for output. In this way, n short time analyses will be available for a given observation
period T together with the results for the total interval. Cumulative probability function plots
long
should preferably be made by using a Gaussian normal distribution scale.
3.6 Outputs
3.6.1 General
The flickermeter diagram in figure 1 shows a number of outputs between blocks 1 and 5. The
outputs marked with an asterisk are not essential, but may allow a full exploitation of the
instrument potential for the investigation of voltage fluctuations. Further optional outputs may
be considered.
3.6.2 Output 1
The aim of optional output 1 and its associated r.m.s. voltmeter is to display the voltage
fluctuation waveform in terms of changes in r.m.s. value of the input voltage. This can be
achieved by squaring, integrating between zero crossings on each half-cycle and square-
rooting the signal.
In order to observe small voltage changes with good resolution, an adjustable d.c. offset and
rectification should be provided.
3.6.3 Output 2
Output 2 is optional and mainly intended for checking the response of block 3 and making
adjustments.
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3.6.4 Output 3
Output 3 is optional and gives an instantaneous linear indication of the relative voltage change
ΔV/V expressed as per cent equivalent of an 8,8 Hz sinusoidal wave modulation. This output is
useful when selecting the proper measuring range.
3.6.5 Output 4
Output 4 is optional and gives the 1 min integral of the instantaneous flicker sensation.
3.6.6 Output 5
Output 5 is mandatory; it represents the instantaneous flicker sensation and can be recorded
on a strip-chart recorder for a quick on-site evaluation, or on magnetic tape for long-duration
measurements and for later processing.
3.6.7 Output 6
Output 6 in block 5 is mandatory and is connected to a serial digital interface suitable for a
printer and a magnetic tape recorder. Analogue plots of the cumulative probability function can
be obtained directly from this block by using another digital-to-analogue converting interface.
4 Specification
4.1 Analogue response
The overall analogue response from the instrument input to the output of block 4 is given in
tables 1 and 2 for sinusoidal and rectangular voltage fluctuations. One unit output from block 4
corresponds to the reference human flicker perceptibility threshold. The response is centred at
8,8 Hz for sinusoidal modulation.
The prescribed accuracy is achieved if the input values for sine and square-wave modulations
are within ± 5 % of the tabulated values, for an output of one unit of perceptibility.
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Table 1 – Normalized flickermeter response for sinusoidal
voltage fluctuations
(input relative voltage fluctuation ΔV/V for one unit of
perceptibility at output)
Hz Voltage fluctuation Hz Voltage fluctuation
% %
0,5 2,340 9,5 0,254
10,0 0,260
1,0 1,432
1,5 1,080 10,5 0,270
2,0 0,882 11,0 0,282
2,5 0,754 11,5 0,296
0,654 12,0 0,312
3,0
3,5 0,568 13,0 0,348
4,0 0,500 14,0 0,388
4,5 0,446 15,0 0,432
5,0 0,398 16,0 0,480
5,5 0,360 17,0 0,530
6,0 0,328 18,0 0,584
6,5 0,300 19,0 0,640
7,0 0,280 20,0 0,700
7,5 0,266 21,0 0,760
8,0 0,256 22,0 0,824
8,8 0,250 23,0 0,890
24,0 0,962
1,042
25,0
Table 2 – Normalized flickermeter response for rectangular
voltage fluctuations
(input relative voltage fluctuation ΔV/V for one unit
of perceptibility at output)
Hz Voltage fluctuation Hz Voltage fluctuation
% %
0,5 0,514 9,5 0,200
1,0 0,471 10,0 0,205
1,5 0,432 10,5 0,213
2,0 0,401 11,0 0,223
2,5 0,374 11,5 0,234
3,0 0,355 12,0 0,246
3,5 0,345 13,0 0,275
4,0 0,333 14,0 0,308
4,5 0,316 15,0 0,344
5,0 0,293 16,0 0,376
5,5 0,269 17,0 0,413
6,0 0,249 18,0 0,452
6,5 0,231 19,0 0,498
0,546
7,0 0,217 20,0
7,5 0,207 21,0 0,586
8,0 0,201 22,0 0,604
8,8 0,199 23,0 0,680
24,0 0,743
4.2 Input transformer
The input voltage transformer shall accept a wide range of nominal mains voltages and adapt
them to the maximum level compatible with the operation of the following circuits. The most
common rated voltages, assuming a –30 % to +20 % deviation, are listed in table 3.
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Table 3 – Ranges of rated input voltages
Rated input – 30 % + 20 %
voltage V r.m.s. V r.m.s.
V r.m.s.
57,7 40 68
100 70 120
80,5 138
115
127 89 152
160 112 192
220 154 264
230 161 276
240 168 288
380 266 456
420 294 504
The prescribed total range shall therefore be 40 V r.m.s. to 504 V r.m.s.
It is advisable to keep the variations of secondary voltage within a maximum excursion of 1
to 3,5 times. The transformer should have at least two taps. The transforming ratio for primary
to secondary should be 504/V and 276/V and 138/V for the taps, where V is the reference
R R R R
voltage value (see 4.3).
The pass bandwidth of the input stage of the flickermeter shall not introduce a significant
attenuation up to at least 700 Hz.
The insulation between the primary winding and all other parts not connected to it shall be
capable of withstanding 2 kV r.m.s. for 1 min. Suitably connected electrostatic shielding shall
be provided between windings.
4.3 Voltage adaptor
This circuit shall keep the r.m.s. level of the modulated 50 Hz voltage at the input of block 2, at
a constant reference value V according to the specification of the input transformer, without
R
modifying the modulating relative fluctuation. It shall have a response time (10 % to 90 % of the
final value) to a step variation of the r.m.s. input value equal to 1 min. The operating range of
this circuit shall be sufficient to ensure a correct reproduction of input voltage fluctuations
creating flicker.
4.4 Internal generator for calibration checking
The internal generator shall provide a sine wave at mains frequency modulated by a
(50/17) Hz = 2,94 Hz, rectangular voltage fluctuation.
Checking shall be made by providing an indication that shows alignment with a reference mark
or value. The significant characteristics of this circuit are the following:
– carrier phase-locked to the mains;
– ΔV/V modulation 1 %;
– carrier level suitable for all measuring ranges;
– accuracy of modulating frequency 1 %.
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4.5 Squaring demodulator
This circuit included in block 2 shall give as a component of its output a voltage linearly related
to the amplitude of the fluctuation modulating the input. The input operating range of the
demodulator shall be capable of accepting up to 150 % of the reference value V .
R
4.6 Weighting filters
These filters, included in block 3, are used to:
– eliminate the d.c. component and the component at twice the mains frequency present at
the output of the demodulator (the amplitude of higher frequency components is negligible);
– weight the voltage fluctuation according to the lamp-eye-brain sensitivity.
The filter for the suppression of the unwanted components incorporates a first order high-pass
(suggested 3 dB cut-off frequency at about 0,05 Hz) and a low-pass section, for which a 6th
order Butterworth filter with a 35 Hz 3 dB cut-off frequency is suggested.
This suggestion takes into account the fact that the component at twice the mains frequency is
also attenuated by the weighting filter of block 3. A band stop or notch filter tuned at this
frequency may also be added to increase the resolution, but it shall not significantly affect the
response of the instrument to frequencies within the measurement bandwidth.
4.7 Overall response from input to output of block 3
A suitable transfer function for block 3, assuming that the carrier suppression filter defined
above has negligible influence inside the frequency bandwidth associated to voltage fluctuation
signals, is of the following type:
ksω 1 +s/ ω
1 2
Fs() = ×
2 2
()1 ++s/ωω (1 s/ )
s + 2λωs +
3 4
1
where s is the Laplace complex variable. Indicative values for the parameters are listed
below:
k = 1,748 02 λ =2 π 4,059 81
ω =2 π 9,154 94 ω =2 π 2,279 79
1 2
ω =2 π 1,225 35 ω =2 π 21,9
3 4
NOTE – Overall accuracy is achieved by compliance with the test specifications in clause 5.
4.8 Range selector
The range selector determines the instrument sensitivity, varying the gain according to the
amplitude of the voltage fluctuation to be measured.
The measuring ranges expressed as relative voltage change V/V for an 8,8 Hz sine wave
Δ
modulation are 0,5; 1; 2; 5; 10; 20 %.
The range 20 % is optional as at large depths of modulation, non-linearity of the demodulator
may introduce significant errors.
If an intermediate range is not implemented, then the instrument resolution shall be increased
so as to ensure equivalent performance over the missing range.
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4.9 Squaring multiplier and sliding mean filter
Block 4 performs two functions:
– squaring of the weighted flicker signal to simulate the non-linear eye-brain perception;
– sliding mean averaging of the signal to simulate the storage effect in the brain.
The squaring operator shall have input and output operating ranges sufficient to accommodate
the admissible flicker level at 8,8 Hz.
The sliding mean operator shall have the transfer function of a first order low-pass
...
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