CISPR TR 16-3:2003/AMD2:2006

TECHNICAL
CISPR
REPORT
16-3
AMENDMENT 2
2006-11
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE
Amendment 2
Specification for radio disturbance and immunity
measuring apparatus and methods –
Part 3:
CISPR technical reports
© IEC 2006 Droits de reproduction réservés ⎯ Copyright - all rights reserved
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– 2 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

FOREWORD
This amendment has been prepared by CISPR subcommittee A: Radio interference

measurements and statistical methods.

The text of this amendment is based on the following documents:

DTR Report on voting
CISPR/A/659/DTR CISPR/A/681/RVC

CISPR/A/662/DTR CISPR/A/678/RVC

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 maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication
will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
_____________
Page 7
3 Definitions
Add, on page 9, after 3.11, the following new definitions:
3.12
weighting (e.g. of impulsive disturbance)
the pulse-repetition-frequency (PRF) dependent conversion (mostly reduction) of a peak-
detected impulse voltage level to an indication which corresponds to the interference effect on
radio reception
NOTE 1 For the analog receiver, the interference effect is the psychophysical annoyance, i.e. a subjective quantity
(audible or visual, usually not a certain number of misunderstandings of a spoken text).
For the digital receiver, the interference effect may be defined by the critical Bit Error Ratio (BER) (or Bit Error
Probability (BEP)), for which perfect error correction can still occur, or by another objective and reproducible
parameter.
3.13
weighting characteristic
the peak voltage level as a function of PRF for a constant effect on a specific radio-
communication system, i.e., the disturbance is weighted by the radio communication system
itself
TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 3 –

3.14
weighting function
weighting curve
the relationship between input peak voltage level and PRF for constant level indication of a

measuring receiver with a weighting detector, i.e. the curve of response of a measuring receiver

to repeated pulses
3.15
weighting factor
the value in dB of the weighting function relative to a reference PRF or relative to the peak value

3.16
weighting detector
detector which provides an agreed weighting function
3.17
weighted disturbance measurement
measurement of disturbance using a weighting detector
Page 10
4 Technical Reports
Add, after the existing subclause 4.7 published in Amendment 1, the following new subclauses
4.8 and 4.9:
4.8 Background material on the definition of the r.m.s.-average weighting detector
for measuring receivers
4.8.1 Introduction – purpose of weighted measurement of disturbance
Generally, a weighted measurement of impulsive disturbance serves the purpose of minimizing
the cost of disturbance suppression, while keeping an agreed level of radio protection. The
weighting of a disturbance for its effect on modern digital radiocommunication services is
important for the definition of emission limits that will protect these services. Amendment 1 of
CISPR 16-1-1 defines a detector that is a combination of an r.m.s. and an average detector. The
selection of the type of detector and of the transition between these detector functions is based
on measurements and theoretical investigations.
4.8.2 General principle of weighting – the CISPR quasi-peak detector
The effect on radiocommunication services depends on the type of interference (e.g. broadband

or narrowband, pulse rate etc.) and on the type of service itself. The effect of the pulse rate was
recognized a short time after the CISPR was founded in 1933. As a result, the quasi-peak
weighting receiver for the frequency range of 150 kHz to 1 605 kHz was defined as shown for
band B in Figure 4.8.1. However in CISPR 1 [1] it was already accepted that “Subsequent
experience has shown that the r.m.s. voltmeter might give a more accurate assessment” but the
quasi-peak type of voltmeter has been retained for certain reasons – mainly for continuity.

– 4 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

30 MHz-1000 MHz (band C and D)
0,15 MHz-30 MHz (band B)
9 kHz-150 kHz (band A)
43,5 dB
–4
–8
–12
100 1 kHz
Single pulse Pulse rate
1 10
IEC  2010/06
Figure 4.8.1 – Weighting curves of quasi-peak measuring receivers
for the different frequency ranges as defined in CISPR 16-1-1.
The weighting factor is shown relative to a reference pulse rate (25 Hz or 100 Hz)
4.8.3 Other detectors defined in CISPR 16-1-1
• Peak detector
The peak detector follows the signal at the output of the IF envelope detector and holds the
maximum value during the measurement time (also called dwell time) until its discharge is
forced. This indication is independent of the pulse repetition frequency (PRF).
• Average detector
The average detector determines the linear average of the signal at the output of the IF envelope
detector. It should be kept in mind that for low PRFs, CISPR 16-1-1 specifies the average
detector measurement result as the maximum scale deflection of a meter with a time constant

specified for the quasi-peak detector. This is necessary to avoid reduced level indication for a
pulse modulated disturbance by using long measurement times. The weighting function varies
with 20 dB per decade of the PRF (see Figure 4.8.2).
• RMS detector
The r.m.s. detector determines the r.m.s. value of the signal at the output of the IF envelope
detector. Despite being mentioned in [1] and being described in CISPR 16-1-1, at the time of
writing of this report it has not been put to practical use in CISPR product standards. The
weighting function varies with 10 dB per decade of the PRF (see Figure 4.8.2). Up to now, no
meter time constant applies for the r.m.s. detector for intermittent, unsteady and drifting
narrowband disturbances.
Rel. input level for constant indication  dB

TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 5 –

Comparison of detector weighting functions
(example for bands C and D with 120 kHz bandwidth)

60 Average
RMS
Quasi-Peak
Peak
1 10 100 1 000 10 000 100 000 1 000 000
f /Hz
p
IEC  2011/06
Figure 4.8.2 – Weighting curves for peak, quasi-peak, r.m.s. and linear average detectors
for CISPR bands C and D
4.8.4 Procedures for measuring pulse weighting characteristics of digital
radiocommunications services
All modern radio services use digital modulation schemes. This is not only true for mobile radio
but also for audio and TV. Procedures for data compression and processing of analog signals
(voice and picture) are used together with data redundancy for error correction. Usually, up to a
certain critical bit-error ratio (BER) the system can correct errors so that perfect reception
occurs.
Whereas analog radio systems require signal-to-noise ratios of as much as 50 dB for satisfactory
operation, in general, digital radio communication systems allow error-free operation down to
signal-to-noise ratios of approximately 10 dB. However the transition region from error-free
operation to malfunction is small. Therefore planning guidelines for digital radio are based on
almost 100 % coverage. When a digital radio receiver operates at low input levels, the
susceptibility to radio disturbance is important. In mobile radio reception, the susceptibility to

radio disturbance is combined with the problem of multi-path propagation.
4.8.4.1 Principles of measurement
The significance of the weighting curve for band B in Figure 4.8.1 is as follows: to a listener the
degradation of reception quality, caused by a 100-Hz pulse, is equivalent to the degradation from
a 10-Hz pulse, if the pulse level is increased by an amount of 10 dB. In analogy to the above, an
–3
interference source with certain characteristics will produce a certain BER, e.g. 10 in a digital
radiocommunication system, when the interfering signal is received in addition to the radio
signal. The BER will depend e.g. on the pulse repetition frequency (PRF) and the level of the
interfering signal. In order to keep the BER constant, the level of the interfering signal will have
to be readjusted while the PRF is varied. This level variation vs. PRF determines the weighting
characteristics. Measurement systems with BER indication are needed to determine the required
level of the interfering signal for a constant BER as e.g. shown in Figure 4.8.3.
Weighting factor/dB
– 6 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

BER
Radio signal
generator
Radio
receiver
Interference
source
IEC  2012/06
Figure 4.8.3 – Test setup for the measurement of the pulse weighting characteristics
of a digital radiocommunication system
The test setup shown in Figure 4.8.3 consists of a radio signal generator that transmits the
wanted radio signal to the receiver. For the determination of the BER, the radio receiver either
has to know the original bit sequence for comparison with the detected bit sequence or the latter
must be looped back to the radio signal generator for comparison with the original. Both systems
are available and have been used for tests. Mobile radio testers, e.g., apply the loop-back
principle.
4.8.4.2 Generation of the interference signal
A signal generator with pulse-modulation capability can be used to generate the interference
signal. For correct measurements, the pulse modulator requires a high ON/OFF ratio of more
than 60 dB. Using the appropriate pulse width, the interference spectrum can be broadband or
narrowband, where the definition of broadband and narrowband is relative to the communication
channel bandwidth. Figure 4.8.4 gives an example of an interference spectrum used for the
determination of weighting characteristics.
* RBW 9 kHz Marker 1 [T1]
VBW 30 kHz  61,89 dBμV
Ref. 90 dBμV *
Att. 0 dB SWT 3,1 s 128 000 000 000 MHz
B
1 PK*
CLRWR
PRN
–10
Center 128 MHz 5 MHz Span 50 MHz
IEC  2013/06
Figure 4.8.4 – Example of an interference spectrum: pulse modulated carrier
with a pulse duration of 0,2 μs and a PRF < 10 kHz

TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 7 –

With increasing pulse duration, the main lobe of the spectrum becomes narrower. This is also

used to study the effect of narrowband pulses on radiocommunication systems. The advantage

of using a band-limited pulse spectrum instead of a broadband pulse generator is to avoid

overloading the receiver under test. Otherwise non-linearity effects could cause deterioration of

the weighting characteristics. In addition to pulse-modulated carriers, unmodulated carriers can

be used to determine the sensitivity of different systems to narrowband (CW signal) EMI.

Extensive measurements have also been presented in [2] with on/off-keying of a QPSK-

modulated signal, thus keeping the spectrum width wider than the system bandwidth even with

longer pulse durations. Since actual receivers do not provide BER indication, the method
described in the ITU Recommendation 1368 was used as the failure criteria: DVB-T reception

was regarded as distorted when more than one visible erroneous block was shown on the screen

within an observation period of 20 s. Alternatively, any picture-freeze, also for short periods, was
regarded as a failure. For DRM, the reception was considered as distorted when the system
showed more than one dropout in a 20 s observation time.
Further measurements have been made with spread-spectrum modulated carriers in order to
study the effect of spread-spectrum clock interference on wideband radiocommunication services
(see [3] and [4]).
Table 4.8.1 – Overview of types of interference used in the experimental study
of weighting characteristics
Interference signals Pulse-modulated On/Off-keyed QPSK- Spread-spectrum
modulated modulated
Pulse width in relation T < 1/B to 100/B T < 1/B to 100/B Continuous
to signal bandwidth
T = pulse width, B = radio signal bandwidth
4.8.4.3 Other principles of measurement
The receiver under test should receive a signal that is just sufficient to give quasi error-free
–7 –3
reception (e.g. a BER = 10 or a factor of 10 lower than the critical BER). Thus the receiver
operates like a receiver at the rim of a coverage area, where a disturbance above the emission
limit can easily cause interference.
For radio telephone systems, where the downlink (to the mobile) and uplink (to the base station)
frequencies are in different bands, the use of a pulse modulated carrier helps to concentrate the
interference on the mobile receiver and thus avoids interference with the loop-back connection.
4.8.5 Theoretical studies
The work of developing measurement procedures considering a digital radio receiver as a

disturbance victim, is a very complex problem since there are many different modulation and
coding schemes to consider as digital communication services are undergoing rapid
development. The results of theoretical studies for radio systems using error correction have
been presented in [5] and [6]. These studies are based on the same fundamental assumptions
that are explained above:
• the BER is the performance parameter of interest for the digital communication system;
• the repetitive pulsed disturbance is the waveform of particular interest;
• the disturbance pulses have a pulse duration that is short compared to the digital symbols
transmitted.
Results for some selected convolutional codes (for more details, see [5]):

– 8 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

A convolutional code is generated by passing the information sequence through a linear finite-
state shift register. In general, the shift register consists of K stages and n algebraic function

generators. The input data to the channel encoder is shifted into and along the shift register k

bits at a time. The number of output bits for each k-input sequence is n bits. The rate R of the

code is defined as n/k. The parameter K is called the constraint length of the convolutional code.

In Figures 4.8.5 a) and b) as well as 4.8.6 a) and b) the r.m.s. and peak values corresponding to

–3
a constant BER of 10 are shown for different convolutional codes and binary phase shift keying

1)
(BPSK) modulation. These results have been simulated with ACOLADE© (Advanced

Communication Link Analysis and Design Environment). In the graphs, the pulse repetition

frequency of the disturbance is presented as related (normalized) to the gross-bit rate (or symbol

rate) R of the communication system. The simulation is done in the band-pass domain. This
s
means that the results can be transformed to an arbitrary carrier frequency. The disturbance
pulse width is 10 % of the bit duration time. For the lowest rate R = ¼, the r.m.s. value is
approximately constant down to the critical point where it increases rapidly. Thus, for a well-
protected system, the r.m.s. value corresponding to a constant BER is constant with respect to
the pulse repetition frequency of the repetitive pulsed disturbance.
50 50
Uncoded
Conv. R=2/3, K=3
Uncoded
Conv. R=1/2, K=3
Conv. R=1/2, K=3
Conv. R=1/4, K=3 0
Conv. R=1/2, K=5
−10
−3 −2 −1 0 1
−10
10 10 10 10 10 −3 −2 −1 0 1
10 10 10 10 10
Normalized Pulse Repetition Frequency
Normalized pulse repetition frequency Normalized Pulse Repetition Frequency

IEC  2014/06
Normalized pulse repetition frequency
IEC  2015/06
Figure 4.8.5 a) – The r.m.s. level for constant
Figure 4.8.6 a) –The r.m.s. level for constant
BEP for three K=3, convolutional codes of
BEP for two rate ½, convolutional codes
different rate
Uncoded
Uncoded
Conv. R=1/2, K=3
Conv. R=2/3, K=3
Conv. R=1/2, K=5
Conv. R=1/2, K=3
Conv. R=1/4, K=3
40 40
20 20
−3 −2 −1 0 1 −3 −2 −1 0 1
10 10 10 10 10
10 10 10 10 10
Normalized Pulse Repetition Frequency
Normalized Pulse Repetition Frequency
Normalized pulse repetition frequency Normalized pulse repetition frequency
IEC  2017/06
IEC  2016/06
Figure 4.8.5 b) – The peak level for constant
Figure 4.8.6 b) –The peak level for constant BEP
BEP for three K=3, convolutional codes of
for two rate ½, convolutional code
different rate
—————————
1)
ACOLADE© is an example of a suitable product available commercially. This information is given for the

convenience of users of this Technical Report and does not constitute an endorsement by IEC of this product.
Peak value for constant BEP  dBV RMS value for constant BEP  dBV
Peak value for constant BEP [dBV] RMS value for constant BEP [dBV]
Peak value for constant BEP  dBV
RMS value for constant BEP  dBV
Peak value for constant BEP [dBV] RMS value for constant BEP [dBV]

TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 9 –

The results in Figure 4.8.5 show the following: above the symbol rate R , the weighting
s
characteristic follows the r.m.s. value of the impulsive signal that causes the interference.

Below R , the weighting characteristic depends on the amount of coding: for the uncoded

s
signal, the peak value increases with less than 10 dB per decade as the PRF decreases. With

better coding, the part of the weighting characteristic with flat response becomes shorter.

Therefore, it is important to characterize real radiocommunication systems in order to obtain

meaningful results.
4.8.6 Experimental results
The methods described in 4.8.4 have been used for the measurement results in this part. The

test signals are described where necessary.
4.8.6.1 Weighting in band A
For band A, i.e. below 150 kHz, no measurement results of digital radiocommunication
systems are available.
NOTE Weighting of radio disturbance generally requires a consideration of intermittent, unsteady and drifting
narrowband disturbances. Therefore the concept of defining a corner frequency, below which the average detector
becomes effective has been applied to band A as well, using the corner frequency proposed for band B, since the
original CISPR specification of the r.m.s. detector does not apply a meter time constant.
4.8.6.2 Weighting in band B
Weighting of interference to the Digital Radio Mondial (DRM) Broadcast System
At the World Radio Conference (WRC) in June 2003, the new Digital Radio Mondial was
officially started. During the four week duration of the conference, a great number of special
DRM transmissions became available from many radio stations. The measurements reported
below, were taken on 8 July, 2003, when a great number of transmissions were still available.
DRM uses OFDM (Orthogonal Frequency Division Multiplex) with 200 carriers. The occupied
bandwidth of each transmission is 10 kHz. In addition to the digitized audio signal, a certain
amount of data (radio station information etc.) is transmitted. A conventional AM receiver can
be used to downconvert the signal to an IF of 12 kHz, which is then decoded using a digital
signal processor and a special DRM software radio.
During the time of measurement, the radio stations in table 4.8.2 were received at the station
near Munich, with amateur dipole antennas mounted on the roof with a higher receive input
voltage (50 to 60 dBµV) than required for the experiment.

– 10 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

Table 4.8.2 – DRM radio stations received for the measurement
of the weighting characteristics

Frequency Beam Target Av. DRM power Program Transmit site

kHz kW
5975 060 W Europe 40 T-Systems Jülich

Media Broadcast
6095 ND Europe 35 RTL/music and Junglinster,

short Luxembourg
announcements
6140 ND W & C Europe 40 DW English Jülich

7320 105 W & C Europe 33 BBCWS Rampisham
13605 037 C Europe 6 IBB/R. Sawa Morocco
15440 040 W & C Europe 80 DW English Sines
“W & C” means West and Central (Europe)
The various transmissions were available for 1h or 2 h. The measurement results (weighting
characteristics) were essentially the same for all frequencies, even if the amount of data
transmitted in addition to the audio signal was not the same. Time dependent fading of the
input signal had to be compensated for manually using a step attenuator that was inserted in
the antenna connection, see Figure 4.8.7.
Principally the same type of interference signal was generated as in Figure 4.8.4. However,
for a signal with an occupied bandwidth of 10 kHz, it is possible to use a longer pulse duration
(10 μs or more).
Step Attenuator
for manual
Antenna
fading compensation
IF Out
AM Rec. PC
Sig. Gen.
With pulse
modulation IEC  2018/06
Figure 4.8.7 – Test setup for the measurement of weighting curves for Digital Radio
Mondial (DRM). The received signal was downconverted to an IF of 12 kHz for decoding

by special hard and software in a personal computer (PC)
Since no indication of BER was available, the “Audio” status indication on the PC (DRM
software radio display) was used as a criterion. As soon as the interference becomes too
high, the “Audio” status indication will turn from green to red.
As explained earlier, the signal level is attenuated so that the reception quality is just enough.
The weighting characteristic (see Figure 4.8.8) shows a 10 dB/decade increase of the
interference signal for PRFs between 1 kHz and 5 Hz. The nonlinearities are mainly due to
uncompensated fading of the input signal. A detailed weighting curve is shown for a pulse
width of 10 μs. For higher pulse widths, the weighting curve was measured only at three
(resp. four) points to verify the 10 dB/decade behaviour. Below a PRF of 5 Hz, the weighting
curve rises suddenly. And below about 2 Hz, the signal cannot be disturbed by the pulse
width of 500 μs. However lightning strokes are reported to generate longer dropouts, which
indicates that longer clicks might cause such dropouts as well.

TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 11 –

DRM at 5,975 MHz; 6,095 MHz; 6,140 MHz; 7,320 MHz; 13,605 MHz;

data rate 20,9 kBit/s; signal level kept at constant SNR

width 1E-05s
width 5E-05s
width 1E-04s
50 width 5E-04s
1 10 100 1000 10 000
f /Hz
p
IEC  2019/06
Figure 4.8.8 – Weighting characteristics for DRM signals for various pulse widths
of the pulse-modulated carrier. Since the DRM signals are actual radio signals,
the exact modulation scheme is not known
The report [2] describes the following DRM signals and two receiver types for the
measurements:
• Mode B, Modulation 16/64QAM, Interleave 2 sec, protection level 1 / 0
• Mode B, Modulation 16/64QAM, Interleave 2 sec, protection level 0 / 0
The interference signal for Figures 4.8.9 and 4.9.10 is a pulse-modulated carrier with
additional QPSK modulation in order to generate a wide bandwidth of the interference
spectrum as explained in 4.8.4.2.

DRM Mode B 16/64QAM prot. level 0: Trend
140 dBμV
200 ns
1 μs
120 dBμV
10 μs
100 μs
1 ms
100 dBμV
10 ms
80 dBμV
60 dBμV
40 dBμV
20 dBμV
0 dBμV
1 Hz 10 Hz 100 Hz 1 000 Hz 10 000 Hz
Pulse repetition frequency
IEC  2020/06
Figure 4.8.9 – Weighting characteristics for DRM protection level 0:
average of results for two receivers
Pulse level (Pk)
dBμV
– 12 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

DRM Mode B 16/64QAM prot. level 1: Trend

140 dBμV
200 ns
1 μs
120 dBμV
10 μs
100 μs
100 dBμV
1 ms
10 ms
80 dBμV
60 dBμV
40 dBμV
20 dBμV
0 dBμV
1 Hz 10 Hz 100 Hz 1 000 Hz 10 000 Hz
Pulse repetition frequency
IEC  2021/06
Figure 4.8.10 – Weighting characteristics for DRM protection level 1:
average of results for two receivers
The weighting characteristics in Figures 4.8.9 and 10 show a 10 dB/decade slope down to
approx. 100 Hz. Since there is no other digital radio system in band B, the corner frequency of
the proposed RMS/AV detector between r.m.s. and linear average detection for this frequency
band can only be based on the results of DRM (see 4.8.7). A corner frequency of 10 Hz is
therefore proposed for band B as a compromise between the two results.
4.8.6.3 Weighting in bands C/D
4.8.6.3.1 Weighting of impulsive interference to Digital Video Broadcast Terrestrial
(DVB-T)
• Test setup
One test setup for DVB-T consists of a DVB-T signal generator and a DVB-T measuring
receiver. The components are connected via coaxial cables. The interference signal (a pulse-

modulated carrier, see Figure 4.8.4 for an example of the spectrum) is fed into the signalling
connection via a combiner.
The parameters used are the following.
DVB-T uses COFDM (Coded Orthogonal Frequency Division Multiplex) with 6817 (8k) or 1705
(2k) carriers. The OFDM carriers may be modulated either with QPSK (Quadrature Phase
Shift Keying) or with 64 QAM (Quadrature Amplitude Modulation), resp. 16 QAM. QAM is
preferred to QPSK as QAM allows higher data transfer rates. The transmission code rate CR
is defined by CR = number of information bits/(number of information bits + error protection
bits). Values of CR = 2/3 and 3/4 are used in actual systems. Each COFDM symbol is
followed by a guard interval GI which is GI = 1/8 in actual systems. The DVB-T modulation
and coding system allows many combinations, of which only a few are relevant. Therefore the
parameters used in systems operating in some European countries have been selected.
These allow transmission rates between 14,745 Mbit/s and 24,88 Mbit/s (see Table 4.8.4)
depending on modulation and code rate. Different coders and decoders are used in the
system. The bit-error ratio (BER) reading can be taken before the Viterbi decoder as well as
Pulse level (Pk)
TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 13 –

before and after the Reed Solomon decoder of the measuring receiver. A comparison is given

in Table 4.8.3. The transmission level is set so that the BER after the Reed Solomon decoder

–8
without interference is just below 10 . This results in different signal levels depending on the

system parameters. The interference levels have then been adjusted to a critical value of BER
–4
= 2,0*10 before the Reed Solomon decoder.

For the BER measurement, the modulator generates a Pseudo Random Binary Sequence

(PRBS) as data stream. The evaluation of the data stream is done in the receiver in two

different procedures. The BER before Viterbi and before Reed-Solomon is evaluated by

correlation. Flags in the bit stream are used to determine the BER after Reed-Solomon. If the
decoder does not recognize a flag as correct, the following bit combination is determined to

be false.
The relationship in Table 4.8.3 was found experimentally between the bit error ratios before
and after the Viterbi and Reed Solomon decoders for two pulse rates.
Table 4.8.3 – Comparison of BER values for the same interference level
Pulse rate 10 k 500 k
Hz
–2 –3
BER before Viterbi decoder 1,5*10 4,4*10
–4 –4
BER before Reed Solomon 2,0*10 2,0*10
–6 –8
BER after Reed Solomon 1,0*10 1,0*10

–4
So, the results with BER measured before Reed Solomon (with 2,0*10 ) and after Reed
–6
Solomon (with 1,0*10 ) are roughly comparable.
Table 4.8.4 – Transmission parameters of DVB-T systems used in various countries
Country Modulation Code rate Guard interval Transfer rate
France/UK 64QAM 2k 3/4 1/8 24,88 Mbit/s
Spain 64QAM 8k 3/4 1/8 24,88 Mbit/s
Germany 16QAM 8k 2/3 1/8 14,745 Mbit/s

The measurement results are presented in Figures 4.8.11, 4.8.12 and 4.8.13. In all tests, the
interference signal leading to these results are pulse-modulated carriers.

– 14 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

–4
DVB-T f = 500 MHz, 64 QAM 2k, CR 3/4, GI 1/8, BER before RS = 2 × 10 ,

-61,5 dBm, 24,88 Mbit/s (FR, UK)

width 0,1E-06s
width 0,2E-06s
width 0,5E-06s
width 1,0E-06
width 2,0E-06
width 5,0E-06s
width 10E-06
1 10 100 1 000 10 000 100 000 1 000 000 10 000 000
f /Hz
p IEC  2022/06
Figure 4.8.11 – Weighting characteristics for DVB-T with 64QAM 2k, CR 3/4
(as used in France and United Kingdom)

–4
DVB-T f = 500 MHz, 64 QAM 8k, CR 3/4, GI 1/8, BER before RS = 2 × 10 ,
-61,7 dBm, 24,88 Mbit/s (ES)
width 0,1E-06s
width 0,2E-06s
width 0,5E-06s
width 1,0E-06
width 2,0E-06
width 5,0E-06s
width 10E-06
1 10 100 1 000 10 000 100 000 1 000 000 10 000 000
f /Hz
p
IEC  2023/06
Figure 4.8.12 – Weighting characteristics for DVB-T with 64QAM 8k, CR 3/4
(as used in Spain)
dBμV dBμV
TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 15 –

–4
DVB-T f = 500 MHz, 16 QAM 8 k, CR 2/3, GI 1/8, BER before RS = 2 × 10 ,

-61,8 dBm, 14,745 Mbit/s (DE)
width 0,1E-06s
width 0,2E-06s
width 0,5E-06s
width 1,0E-06
100 width 2,0E-06
width 5,0E-06s
width 10E-06
1 10 100 1 000 10 000 100 000 1 000 000 10 000 000
f /Hz
p
IEC  2024/06
Figure 4.8.13 – Weighting characteristics for DVB-T with 16QAM 8k, CR 2/3
(as used in Germany)
A number of 6 different receiver types were tested in report [2] for DVB-T with 16QAM 8k, CR
2/3 and for DVB-T with 64QAM 8k, CR 2/3. To get receiver independent results, the individual
characteristics were combined using average values inside the range where all receivers
offered a result. Excluded were two receivers in PRF ranges, where they showed a non-
typical behavior. These combined results are shown in the “trend” characteristics in
Figures 4.8.14 and 4.8.15. The interference signal for both figures is a pulse-modulated
carrier with additional QPSK modulation in order to generate bandwidth of the interference
spectrum at least as wide as the DVB-T signal spectrum as explained in 4.8.4.2.

dBμV
– 16 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

DVB-T 8k 16QAM 2/3: Trend
140 dBμV
50 ns
200 ns
0,5 μs
120 dBμV
1 μs
5 μs
100 dBμV
10 μs
80 dBμV
60 dBμV
40 dBμV
20 dBμV
0 dBμV
10 Hz 100 Hz 1 000 Hz 10 000 Hz 100 000 Hz
Pulse repetition frequency
IEC  2025/06
Figure 4.8.14 – Average weighting characteristics of 6 receiver types
for DVB-T with 16QAM
DVB-T 8k 64QAM 2/3: Trend
120 dBμV
50 ns
200 ns
0,5 μs
100 dBμV
1 μs
5 μs
10 μs
80 dBμV
60 dBμV
40 dBμV
20 dBμV
0 dBμV
10 Hz 100 Hz 1 000 Hz 10 000 Hz 100 000 Hz
Pulse repetition frequency
IEC  2026/06
Figure 4.8.15 – Average weighting characteristics of 6 receiver types
for DVB-T with 64QAM
Pulse level (Pk)
Pulse level (Pk)
TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 17 –

• Interpretation of the results

In Figure 4.8.11, the corner frequency can only be assumed to be approx. 100 Hz, whereas in

Figures 4.8.12 and 4.8.13, the corner frequencies can clearly be seen. They however depend

on the interference pulse width as in Figures 4.8.11 and 4.8.13. Since all weighting curves are

given for the shortest pulse (see Figure 4.8.1), also for the corner frequency, the shortest

pulse is always relevant. The system used in Germany shows the most robust performance

against impulsive interference due to its lower code rate and 16QAM 8k modulation.

4.8.6.3.2 Weighting of impulsive interference to other digital radiocommunication

systems operating in CISPR bands C and D

• Digital Audio Broadcasting (DAB)
DAB operates in the VHF (174 MHz to 230 MHz) and the L (1 452 MHz to 1 492 MHz) bands
with a bandwidth of 1,5 MHz per channel using Coded Orthogonal Frequency Division
Multiplex (COFDM) to minimise multipath fading. The audio signal data rate is reduced by
MUSICAM (a masking pattern adapted for Universal Coding and Multiplexing), which is a part
of the MPEG-2 (Moving Picture Expert Group) standard. The total transmitted bit rate is 2,4
Mbit/s. The 1500 subcarriers are modulated using Differential QPSK (DQPSK). The weighting
characteristics in Figure 4.8.16 were measured using a test version of a DAB receiver.
Weighting characteristics of commercial DAB receivers have been presented in report [2].

–4
DAB DQPSK BER = 1,0 × 10
width 0,5E-06s
width 1,0E-06s
width 2,0E-06s
width 5,0E-06s
width 10,0E-06s
100 1 000 10 000 100 000 1 000 000
f/Hz
IEC  2027/06
Figure 4.8.16 – Weighting characteristics for DAB (signal level -71 dBm)
with a flat response down to approximately 1 kHz
dBμV
– 18 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

DAB (QPSK 2/3): Trend
120 dBμV
50 ns
200 ns
0,5 μs
100 dBμV
1 μs
5 μs
10 μs
80 dBμV
60 dBμV
40 dBμV
20 dBμV
0 dBμV
100 000 Hz
10 Hz 100 Hz 1 000 Hz 10 000 Hz
Pulse repetition frequency IEC  2028/06

Figure 4.8.17 – Weighting characteristics for DAB:
average of two different commercial receiver types
The differences between the results in Figures 4.8.16 and 4.8.17 are possibly due to the
different types of the impulsive signal: for Figure 4.8.16 a simple pulse-modulated carrier was
used, whereas for Figure 4.8.17 an on/off-keyed QPSK-modulated signal was used.
• Terrestrial Trunked Radio (TETRA) system
TETRA is used in workshops, the building and construction industries, airports,
transportation/trucking and safety services. It operates in the frequency range 380 MHz to
520 MHz (in some areas also in 870 MHz to 990 MHz) with a data rate of 36 kbit/s per carrier,
an occupied bandwidth of ≈ 25 kHz and channel separations of 12,5, 20 or 25 kHz. Speech
data reduction is done using Algebraic Code Excited Linear Prediction (ACELP) to 4,8 kbit/s
per traffic channel. Up to four traffic channels are normally transmitted on one carrier. The
error protection may be high or low, depending on the code rate. The modulation procedure is
π/4-DQPSK. Figure 4.8.18 shows the measured weighting characteristics for a high code rate
= 1 (low error protection).
Pulse level (Pk)
TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 19 –

TETRA downlink f = 394,0 MHz, BER = 2 %

width 0,1E-06s
width 0,5E-06s
width 1,0E-06s
width 5,0E-06s
width 10,0E-06s
10 100 1 000 10 000 100 000 1 000 000 10 000 000
f/Hz
IEC  2029/06
Figure 4.8.18 – Weighting characteristics for TETRA (signal level – 80 dBm)
for a code rate of 1
Since the pulse spectrum is much wider than the channel bandwidth, all weighting
characteristics are separated by the PRF ratio in dB. Above a PRF of 10 kHz, the slope of
curves is 20 dB/decade, corresponding to the increase of the voltage of the center line of the
interference spectrum. Therefore the weighting characteristics below 10 kHz PRF should be
regarded as relevant.
• Global System for Mobile Communication (GSM)
This digital cellular telecommunication system operates in the 900 MHz (GSM 900) and
1 800 MHz (GSM 1800) frequency bands. The offset between uplink (mobile to base station)
and downlink is 45 MHz (GSM 900) and 95 MHz (GSM 1800) respectively. The occupied
bandwidth is 300 kHz and channel spacing is 200 kHz. Modulation for constant spectrum
envelope is achieved with Gaussian Minimum Shift Keying (GMSK). The error correction
mechanisms applied are different for traffic channels (1b bits) and other bits (Class 2 bits).
Therefore different bit error rates apply: BER, RBER 1b and 2 (residual BER) and FER
(Frame error rates). The test setup and signals of Figures 4.8.3 and 4.8.4 have been used,

with a mobile communication tester as a signal source.
dBμV
– 20 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

GSM 900 Type 1 downlink f = 947,4 MHz RBER 1b = 0,4 % 400 frames -90 dBm

width 0,1E-06s
width 0,5E-06s
width 1,0E-06s
width 2,0E-06s
width 5,0E-06s
width 10,0E-06s
100 1 000 10 000 100 000 1 000 000 10 000 000
f/Hz
IEC  2030/06
Figure 4.8.19 – Weighting characteristics for RBER 1b of GSM (signal level –90 dBm)

GSM 900 Type 1 downlink f = 947,4 MHz RBER 2 = 2 % 400 frames -90 dBm
width 0,1E-06s
width 0,5E-06s
width 1,0E-06s
width 2,0E-06s
width 5,0E-06s
width 10,0E-06s
100 1 000 10 000 100 000 1 000 000 10 000 000

f/Hz
IEC  2031/06
Figure 4.8.20 – Weighting characteristics for RBER 2 of GSM
The characteristics typically rise at 10 dB/decade between 100 kHz and 2 kHz with a steeper
slope below about 2 kHz PRF. Unfortunately measurements below a PRF of 1 kHz were not
possible due to instability of the test system. The results shown in Figures 4.8.19 and 4.8.20
are very similar to the BER and RBER 1b curves of Figure 4.8.21 similar to those published in
[7] and [8] using the simulation software COSSAP. The values obtained in Figure 4.8.21 have
been calculated assuming a pulse-modulated carrier with a pulse duration of 2 μs as the
interference signal.
dBμV
dBμV
TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 21 –

C/I Improvement for τ = 10 μs
BER
FER
RBER 1b
RBER 2
100 1 000 10 000 100 000
f/Hz
IEC  2032/06
Figure 4.8.21 – Carrier-to-interference improvements with decreasing PRF in dB
computed for GSM using COSSAP
• Frequency Modulation (FM) Broadcast System
Based on the assumption that FM broadcast will survive past the transition from analog to
digital radio systems for some time, measurements have been made based on the methods of
report [2] resulting in Figure 4.8.22. The FM signal contained a pilot carrier only; the increase
of noise due to the interference was measured in the demodulated signal. The interference
signal is a pulse-modulated carrier with additional QPSK modulation in order to generate
bandwidth of the interference spectrum at least as wide as the FM signal spectrum as
explained in 4.8.4.2.
2 µs pulses
QP
RMS
100 1 000 10 000 100 000
Pulse repetition frequency  Hz
IEC  2033/06
Figure 4.8.22 – RMS and quasi-peak values of pulse level
for constant effect on FM radio reception
Pulse level  dBμV
dB
– 22 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

Figure 4.8.22 is not a weighting characteristic! It shows that the r.m.s. value of the pulse level

with 2 μs width is closer to being constant than the quasi-peak value. This has been shown

for other pulse widths as well but is not presented here for reasons of space.

4.8.6.4 Weighting for Band E (1 through 18 GHz)

• GSM system
The weighting characteristics found for a mobile operating in the 1 800 MHz (GSM 1800)

frequency band is very similar to the system operating in the 900 MHz (GSM 900) frequency

band (compare Figure 4.8.23 with Figures 4.8.19 through 4.8.21). The offset between uplink

(mobile to base station) and downlink is 95 MHz for GSM 1800. As in Figures 4.8.19 through
4.8.21, the curves are rising below 2 kHz PRF with a slope of more than 20 dB/decade.

GSM 1800 Type 2 downlink f = 1850,8 MHz RBER 1b = 0,4 % 400 frames -90 dBm
width 0,1E-06s
100 width 0,5E-06s
width 1,0E-06s
width 2,0E-06s
width 5,0E-06s
width 10,0E-06s
100 1 000 10 000 100 000 1 000 000 10 000 000
f/Hz
IEC  2034/06
Figure 4.8.23 – Weighting characteristics for RBER 1b of GSM
(signal level –90 dBm)
• Digitally Enhanced Cordless Telephone (DECT) system
DECT is used in homes and offices for distances up to 300 m (in picocells). It provides 10

channels spaced 1,728 MHz apart in the frequency range 1,88 to 1,90 GHz. The occupied
bandwidth is ≈ 1,5 MHz. For speech data reduction Adaptive Differential Pulse Code
Modulation (ADPCM) is used. Modulation is done with Gaussian Mean Shift Keying (GMSK).
The data stream for testing is Pseudo Random Binary Sequence (PRBS).
dBμV
TR CISPR 16-3 Amend. 2 © IEC:2006(E) – 23 –

DECT FP f = 1897,344 MHz, BER = 2 %, Evaluation time = 5,0 s

width 0,1E-06s
width 0,5E-06s
width 1,0E-06s
width 2,0E-06s
width 5,0E-06s
width 10,0E-06s
100 1 000 10 000 100 000 1 000 000 10 000 000
f/Hz
IEC  2035/06
Figure 4.8.24 – Weighting characteristics for DECT (signal level –83 dBm)
The weighting characteristics for DECT show a response near 10 dB/decade in the range
between 50 kHz and 500 kHz PRF in the upper PRF areas for narrow pulses and a steep
slope below about 10 kHz PRF. Only for longer pulse widths, the weighting characteristic is
flat.
• Code Division Multiple Access (CDMA) systems IS-95 and J-STD 008
IS-95/J-STD 008 have been specified by TIA (US Telecommunications Industry Association)
and are used in the frequency ranges 825 MHz to 900 MHz (IS-95) and 1,8 GHz to 2,0 GHz.
The occupied bandwidth is ≈ 1,4 MHz (3 dB: 1,23 MHz). The modulation is done with
Quadrature Phase Shift Keying (QPSK). For the uplink (mobile to base station) the optimum
setting of the receive power at the base station is controlled via power control bits.

IS-95 forward f = 878,49 MHz, FER = 2 %, -83 dBm, full rate
width 0,1E-06s
120 width 0,5E-06s
width 1,0E-06s
width 2,0E-06s
width 5,0E-06s
width 10,0E-06s
100 1 000 10 000 100 000 1 000 000 10 000 000
f/Hz
IEC  2036/06
Figure 4.8.25 – Weighting characteristics for IS-95 (signal level -97 dBm)
with comparatively high immunity to interference
dBμV
dBμV
– 24 – TR CISPR 16-3 Amend. 2 © IEC:2006(E)

J-STD 008 forward f = 1955,0 MHz FER = 2 % full rate -97 dBm

width 0,1E-06s
width 0,5E-06s
width 1,0E-06s
width 2,0E-06s
100 width 5,0E-06s
width 10,0E-06s
100 1 000 10 000 100 000 1 000 000 10 000 000
f/Hz
IEC  2037/06
Figure 4.8.26 – Weighting characteristics for J-STD 008 (signal level –97 dBm)
rd
• 3 Generation Digital Radiocommunication Systems
Two different systems have been investigated:
– Wideband CDMA (W-CDMA), which is going to be deployed in Europe, and
– CDMA2000, which is mainly going to be applied in North America and some other areas.
Tests have been made on both systems. However at the time of testing, available mobile
phones for W-CDMA did not give stable BER results in the test setup (loop back) with the
mobile testers. So, only results for cdma2000 are available now. Results for W-CDMA will
certainly become available at a later date. They have been used later with success for
evaluating the interference effect to spread-spectrum clock signals (see [3] and [4]).
CDMA2000 as described by Third Generation Partnership 2 (3GPP2) is an access method
intended for use in the IMT-2000 proposal for Third Generation (3G) cellular telephone
systems. The system is
...