ETSI TS 102 692 V1.1.1 (2009-06)

Electromagnetic compatibility and Radio spectrum Matters (ERM); RF conformance testing of radar level gauging applications in still pipes

DTS/ERM-TGTLPR-0116

General Information

• Status: Published
• Publication Date: 18-Jun-2009
• Technical Committee: ERM TGTLPR - Tank Level Probing Radar
• Current Stage: 12 - Completion
• Due Date: 14-Jul-2009
• Completion Date: 19-Jun-2009

Standards Content (Sample)

Technical Specification
Electromagnetic compatibility
and Radio spectrum Matters (ERM);
RF conformance testing of
radar level gauging applications in still pipes

2 ETSI TS 102 692 V1.1.1 (2009-06)

Reference
DTS/ERM-TGTLPR-0116
Keywords
radio, UWB
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ETSI
3 ETSI TS 102 692 V1.1.1 (2009-06)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Definitions, symbols and abbreviations . 7
3.1 Definitions . 7
3.2 Symbols . 8
3.3 Abbreviations . 8
4 General testing requirements . 9
4.1 Presentation of equipment for testing purposes . 9
4.2 Choice of model for testing . 9
4.2.1 Declarations by the manufacturer . 9
4.2.2 Marking and equipment identification . 9
4.3 Mechanical and electrical design . 9
4.3.1 General . 9
4.4 Interpretation of the measurement results . 10
4.4.1 Measurement uncertainty is equal to or less than maximum acceptable uncertainty . 10
4.4.2 Measurement uncertainty is greater than maximum acceptable uncertainty . 10
5 Test conditions, power sources and ambient temperatures . 11
5.1 Normal conditions . 11
5.2 External test power source. 11
5.2.1 Internal test power source . 11
5.3 Normal test conditions . 11
5.3.1 Normal temperature and humidity . 11
5.3.2 Normal test power source . 11
5.3.2.1 Mains voltage . 11
5.3.2.2 Other power sources . 11
6 General conditions . 12
6.1 Radiated measurement arrangements . 12
6.2 Modes of operation of the transmitter . 12
6.3 Measuring receiver . 12
7 Interpretation of results . 12
7.1 Measurement uncertainty . 12
8 Methods of measurement and limits for transmitter parameters . 13
8.1 General . 13
8.2 Permitted range of operating frequencies . 13
8.2.1 Definition . 13
8.2.2 Method of measurement . 14
8.2.3 Limits Frequency range . 15
8.3 Emissions . 15
8.3.1 Definition . 15
8.3.2 UWB emissions . 15
8.3.2.1 Method of measurement . 15
8.3.2.2 Limits . 16
8.3.3 Other Emissions (OE) . 17
8.3.3.1 Definition . 17
8.3.3.2 Method of measurement . 17
8.3.3.3 Limits . 18
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4 ETSI TS 102 692 V1.1.1 (2009-06)
8.4 Mitigation techniques . 18
8.4.1 Shielding effects . 19
8.4.2 Frequency domain mitigation . 19
8.4.3 Thermal Radiation . 19
Annex A (normative): Radiated measurements . 20
A.1 Test sites and general arrangements for measurements involving the use of radiated fields . 20
A.1.1 Anechoic Chamber . 20
A.1.2 Anechoic Chamber with a conductive ground plane . 21
A.1.3 Open Area Test Site (OATS) . 22
A.1.4 Test antenna . 23
A.1.5 Substitution antenna . 23
A.1.6 Measuring antenna . 24
A.2 Guidance on the use of radiation test sites . 24
A.2.1 Verification of the test site . 24
A.2.2 Preparation of the EUT . 24
A.2.3 Power supplies to the EUT . 24
A.2.4 Range length . 24
A.2.5 Site preparation . 25
A.3 Coupling of signals . 26
A.3.1 General . 26
Annex B (normative): Installation requirements for radar level gauging applications in still
pipes . 27
Annex C (normative): Requirements on a test pipe . 28
C.1 General . 28
C.2 Measurement setup . 29
Annex D (informative): Measurement antenna and preamplifier specifications . 31
History . 32

ETSI
5 ETSI TS 102 692 V1.1.1 (2009-06)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Electromagnetic compatibility and
Radio spectrum Matters (ERM).
Introduction
The radar level gauges covered by the present document do not use the time domain UWB short pulses. Instead the
radar level gauges covered by the present document use the frequency domain FMCW and/or SFCW. Thus the emission
bandwidth generated by the FMCW and/or SFCW radars is strictly controlled.
The specified requirements in the present document describe the worst case scenario (i.e. the highest emissions to the
environment) and shall be seen as a feasible test method to prove compliance of radar level gauging applications in still
pipes.
The background and related applications have been described in TR 102 750 [i.2] where the applications have been
considered indoor like systems.
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6 ETSI TS 102 692 V1.1.1 (2009-06)
1 Scope
The present document specifies the requirements for radar level gauging applications in still pipes using UWB
technology operating in the 9 to 10,6 GHz frequency range.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
[1] CISPR 16-1 (2003): "Specification for radio disturbance and immunity measuring apparatus and
methods - Part 1: Radio disturbance and immunity measuring apparatus".
[2] ANSI C63.5 (2006): "American National Standard for Electromagnetic Compatibility - Radiated
Emission Measurements in Electromagnetic Interference (EMI) Control - Calibration of Antennas
(9 kHz to 40 GHz)".
[3] Commission Decision 2007/131/EC of 21 February 2007 on allowing the use of the radio
spectrum for equipment using ultra-wideband technology in a harmonised manner in the
Community.
[4] ISO 4266-1 (2002): "Petroleum and liquid petroleum products -- Measurement of level and
temperature in storage tanks by automatic methods -- Part 1: Measurement of level in atmospheric
tanks".
[5] API MPMS 3.1A and 3.1B: "Manual of Petroleum Measurement Standards Chapter 3 - Tank
Gauging, Section 1A - Standard Practice for the Manual Gauging of Petroleum and Petroleum
Products, published on 1 of August 2005 / Tank Gauging Section 1B - Standard Practice for Level
Measurement of Liquid Hydrocarbons in Stationary Tanks by Automatic Tank Gauging, published
on 1 of June 2001".
[6] ITU-R Recommendation P.526-10 (02/07): "Propagation by diffraction".
[7] ETSI TR 100 028 (all parts) (V1.4.1): " Electromagnetic compatibility and Radio spectrum
Matters (ERM); Uncertainties in the measurement of mobile radio equipment characteristics".
ETSI
7 ETSI TS 102 692 V1.1.1 (2009-06)
[8] ETSI TR 102 273 (all parts) (V1.2.1): "Electromagnetic compatibility and Radio spectrum Matters
(ERM); Improvement on Radiated Methods of Measurement (using test site) and evaluation of the
corresponding measurement uncertainties".
2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] ITU-R Recommendation SM.1754: "Measurement techniques of ultra-wideband transmissions".
[i.2] ETSI TR 102 750: "Electromagnetic compatibility and Radio spectrum Matters (ERM); Radar
level gauging applications in still pipes".
3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
dedicated waveguide antenna: device/structure to excite a certain waveguide mode that propagates inside a waveguide
only
duty cycle: ratio of the total on time of the transmitter to the total time
emissions: signals that leaked or are scattered into the air within the frequency range (that includes harmonics) which
depend on equipment's frequency band of operation
equivalent isotropically radiated power (e.i.r.p.): total power transmitted, assuming an isotropic radiator
EUT: radar level gauge with a dedicated waveguide antenna on a dedicated still pipe
Frequency Modulated Continuous Wave (FMCW) radar: radar where the transmitter power is fairly constant but
possibly zero during periods giving a big duty cycle (such as 0,1 to 1)
NOTE: The frequency is modulated in some way giving a very wideband spectrum with a power versus time
variation which is clearly not pulsed.
operating frequency (operating centre frequency): nominal frequency at which equipment is operated
pulsed radar: radar where the transmitter signal has a microwave power consisting of short RF pulses
radiated measurements: measurements that involve the absolute measurement of a radiated field
radiation: signals emitted intentionally inside a tank for level measurements
Stepped Frequency Continuous Wave (SFCW) radar: radar where the transmitter sequentially generates a number
of frequencies with a step size
NOTE: At each moment of transmission, a monochromatic wave is emitted. It is distinguished from FMCW that
has the instantaneous frequency band rather than a single frequency wave. The SFCW radar bandwidth is
synthesized by signal processing to achieve required resolution bandwidth.
still pipe: still-well, stilling-well, guide pole: Vertical, perforated pipe built into a tank to reduce measurement errors
arising from liquid turbulence, surface flow or agitation of the liquid
NOTE: Any equipment made of a perforated steel pipe with diameters varying from a few centimetres up to
several decimetres. The perforations enable the liquid to freely flow into and out of the still pipe at all
levels in a tank. Still pipes are the preferred installation point of a Tank Level Probing Radar inserted
inside a floating or open roof tanks.
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8 ETSI TS 102 692 V1.1.1 (2009-06)
3.2 Symbols
For the purposes of the present document, the following symbols apply:
cl1 cable loss 1
cl2 cable loss 2
dB deciBel
dBi gain in deciBel relative to an isotropic antenna
dBm deciBel reference to 1 mW
E Electrical field strength
E relative dielectric constant of earth materials
R
E
rms Average electrical field strength measured as root mean square
f frequency
f frequency at which the emission is the peak power at maximum
c
G Efficient antenna gain of radiating structure
Gain of the measurement LNA
GLNA
Gain of the measurement antenna
GA
G(f) Antenna gain over frequency
f Highest frequency of the frequency band of operation
H
f Lowest frequency of the frequency band of operation
L
k Boltzmann constant
P Power
P power spectral density
e.i.r.p.
P measured spectral power
m
P unwanted power spectral density
wall, e.i.r.p.
R Distance
rms Root mean square
t time
T Temperature
T pulse rise time
P
Z Free space wave impedance
F0
λ wavelength
c velocity of light in a vacuum
δR range resolution
δt time interval between the arrivals of two signals from targets separated in range by δR
D Duty cycle
P Output power of the signal generator measured by power meter
s
Δf Bandwidth
X Minimum radial distance (m) between the EUT and the test antenna
λ Wavelength
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
e.i.r.p. equivalent isotropically radiated power
EUT Equipment Under Test
FMCW Frequency Modulated Continuous Wave
IT Information Technology
LNA Low Noise Amplifier
OATS Open Area Test Site
OE Other Emissions
RBW Resolution BandWidth
RF Radio Frequency
RMS Remote Management System
SFCW Stepped Frequency Continuous Wave
TLPR Tank Level Probing Radar
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9 ETSI TS 102 692 V1.1.1 (2009-06)
TP Total Power
UWB Ultra WideBand
VBW Video BandWidth
VSWR Voltage Standing Wave Ratio
4 General testing requirements
4.1 Presentation of equipment for testing purposes
The manufacturer shall submit one or more samples of the equipment as appropriate for testing.
Additionally, technical documentation and operating manuals, sufficient to allow testing to be performed, shall be
supplied.
The performance of the equipment submitted for testing shall be representative of the performance of the corresponding
production model. In order to avoid any ambiguity in that assessment, the present document contains instructions for the
presentation of equipment for testing purposes (see clause 4), conditions of testing (see clauses 5 and 6), interpretation
of results (see clause 7) and the measurement methods (see clause 8).
The manufacturer shall offer equipment complete with any auxiliary equipment needed for testing.
4.2 Choice of model for testing
One or more samples of the EUT, as described in annex C, shall be tested.
4.2.1 Declarations by the manufacturer
The manufacturer shall submit the necessary information regarding the equipment with respect to all technical
requirements set by the present document.
4.2.2 Marking and equipment identification
The equipment shall be marked in a visible place. This marking shall be legible and durable.
The marking shall include as a minimum:
• The name of the manufacturer or his trademark.
• The type designation. This is the manufacturer's numeric or alphanumeric code or name that is specific to
particular equipment.
4.3 Mechanical and electrical design
4.3.1 General
The equipment submitted by the manufacturer shall be designed, constructed and manufactured in accordance with
good engineering practice and with the aim of minimizing harmful interference to other equipment and services.
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10 ETSI TS 102 692 V1.1.1 (2009-06)
4.4 Interpretation of the measurement results
The interpretation of the results recorded on the appropriate test report for the measurements described in the present
document shall be as follows:
• the measured value relating to the corresponding limit together with the appropriate mitigation factors as
described in clause 8.4 shall be used to decide whether an equipment meets the requirements of the present
document;
• the measurement uncertainty value for the measurement of each parameter shall be included in the test report.
The measurement uncertainty is explained in clause 7. Additionally, the interpretation of the measured results
depending on the measurement uncertainty is described in clauses 4.4.1 and 4.4.2.
For radiated UWB emissions measurements below 9 GHz and above 10,6 GHz it may not be possible to reduce
measurement uncertainty to the levels specified in clause 7, table 2 (due to the very low signal level limits and the
consequent requirement for high levels of amplification across wide bandwidths). In these cases alone it is acceptable to
employ the alternative interpretation procedure specified in clause 4.4.2.
4.4.1 Measurement uncertainty is equal to or less than maximum
acceptable uncertainty
The interpretation of the results when comparing measurement values with specification limits shall be as follows:
a) When the measured value does not exceed the limit value the equipment under test meets the requirements of
the present document.
b) When the measured value exceeds the limit value the equipment under test does not meet the requirements of
the present document.
c) The measurement uncertainty calculated by the test technician carrying out the measurement shall be recorded
in the test report.
d) The measurement uncertainty calculated by the test technician may be a maximum value for a range of values
of measurement, or may be the measurement uncertainty for the specific measurement undertaken. The
method used shall be recorded in the test report.
4.4.2 Measurement uncertainty is greater than maximum acceptable
uncertainty
The interpretation of the results when comparing measurement values with specification limits should be as follows:
a) When the measured value plus the difference between the maximum acceptable measurement uncertainty and
the measurement uncertainty calculated by the test technician does not exceed the limit value the equipment
under test meets the requirements of the present document.
b) When the measured value plus the difference between the maximum acceptable measurement uncertainty and
the measurement uncertainty calculated by the test technician exceeds the limit value the equipment under test
does not meet the requirements of the present document.
c) The measurement uncertainty calculated by the test technician carrying out the measurement shall be recorded
in the test report.
d) The measurement uncertainty calculated by the test technician may be a maximum value for a range of values
of measurement, or may be the measurement uncertainty for the specific measurement undertaken. The
method used shall be recorded in the test report.
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11 ETSI TS 102 692 V1.1.1 (2009-06)
5 Test conditions, power sources and ambient
temperatures
5.1 Normal conditions
All testing shall be made under normal test conditions.
The test conditions and procedures shall be as specified in clause 5.2.
5.2 External test power source
During tests, the power source of the equipment shall be an external test power source, capable of producing normal
voltages. The internal impedance of the external test power source shall be low enough for its effect on the test results
to be negligible.
The test voltage shall be measured at the point of connection of the power cable to the equipment.
During tests, the external test power source voltages shall be within a tolerance of ±1 % relative to the voltage at the
beginning of each test. The level of this tolerance can be critical for certain measurements. Using a smaller tolerance
provides a reduced uncertainty level for these measurements.
The test power source used shall be stated in the test report.
5.2.1 Internal test power source
For radiated measurements on portable equipment with integral antenna, fully charged internal batteries should be used.
The batteries used should be as supplied or recommended by the manufacturer. If internal batteries are used, at the end
of each test the voltage shall be within a tolerance of less than ±5 % relative to the voltage at the beginning of each test.
5.3 Normal test conditions
5.3.1 Normal temperature and humidity
The normal temperature and humidity conditions for tests shall be any convenient combination of temperature and
humidity within the following ranges:
• temperature + 15 °C to + 35 °C;
• relative humidity 20 % to 75 %.
When it is impracticable to carry out tests under these conditions, a note to this effect, stating the ambient temperature
and relative humidity during the tests, shall be added to the test report.
5.3.2 Normal test power source
5.3.2.1 Mains voltage
The normal test voltage for equipment to be connected to the mains shall be the nominal mains voltage. For the purpose
of the present document, the nominal voltage shall be the declared voltage, or any of the declared voltages, for which
the equipment was designed.
5.3.2.2 Other power sources
For operation from other power sources (primary or secondary), the normal test voltage shall be that declared by the
equipment manufacturer and agreed by the test laboratory. Such values shall be stated in the test report.
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12 ETSI TS 102 692 V1.1.1 (2009-06)
6 General conditions
6.1 Radiated measurement arrangements
For guidance on radiation test sites and general arrangements for radiated measurements, see annexes A and C.
Informative descriptions of radiated measurement arrangements for UWB devices can be found in ITU-R
Recommendation SM.1754 [i.1].
All reasonable efforts should be made to clearly demonstrate that emissions from the UWB transmitter do not exceed
the specified levels, with the transmitter in the far field. To the extent practicable, the equipment under test should be
measured at the distance specified in annex A and with the specified measurement bandwidths. However, in order to
obtain an adequate signal-to-noise ratio in the measurement system, radiated measurements may have to be made at
distances less than those specified in annex A and/or with reduced measurement bandwidths. The revised measurement
configuration should be stated on the test report, together with an explanation of why the signal levels involved
necessitated measurement at the distance employed or with the measurement bandwidth used in order to be accurately
detected by the measurement equipment, and calculations demonstrating compliance.
Where it is not practical to further reduce the measurement bandwidth (either because of limitations of
commonly-available test equipment or difficulties in converting readings taken using one measurement bandwidth to
those used by the respective limit table), and the required measurement distance would be so short that the device would
not clearly be within the far field, the test report shall state this fact, the measurement distance and bandwidth used, the
near field/far field distance for the measurement setup (see clause A.2.4), the measured device emissions, the achievable
measurement noise floor and the frequency range(s) involved.
6.2 Modes of operation of the transmitter
For the purpose of the measurements according to the present document, there shall be a facility to operate the
transmitter in a continuous state, whereby the radar signal is transmitted repeatedly and any gating techniques switched
off.
6.3 Measuring receiver
The term measuring receiver refers to a spectrum analyser. The reference bandwidth of the measuring receiver as
defined in CISPR 16-1 [1] shall be as given in table 1.
Table 1: Reference bandwidth of measuring receiver
Frequency being measured: f Spectrum analyser bandwidth
100 kHz
30 MHz ≤ f < 1 000 MHz
1 MHz
1 000 MHz ≤ f
7 Interpretation of results
7.1 Measurement uncertainty
Interpretation of the results recorded in the test report for the measurements described in the present document shall be
as follows:
• the measured value related to the corresponding limit shall be used to decide whether an equipment meets the
requirements of the present document;
• the value of the measurement uncertainty for the measurement of each parameter shall be separately included
in the test report;
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13 ETSI TS 102 692 V1.1.1 (2009-06)
• the value of the measurement uncertainty shall be wherever possible equal for each measurement, equal to or
lower than the figures in table 2, and the interpretation procedure specified in clause 4.4.1 shall be used.
Table 2: Measurement uncertainty
Parameter Uncertainty
-7
Radio frequency ±1 × 10
Radiated emission of transmitter ±6 dB
Temperature
±1 K
Humidity
±5 %
NOTE: For radiated UWB emissions measurements below 9 GHz and above
10,6 GHz it may not be possible to reduce measurement uncertainty
to the levels specified herein (due to the very low signal level limits
and the consequent requirement for high levels of amplification
across wide bandwidths). In these cases alone it is acceptable to
employ the alternative interpretation procedure specified in
clause 4.4.2.
For the test methods, according to the present document the uncertainty figures shall be calculated according to the
methods described in TR 100 028 [7] and shall correspond to an expansion factor (coverage factor) k = 1,96 or k = 2
(which provide confidence levels of respectively 95 % and 95,45 % in cases where the distributions characterizing the
actual measurement uncertainties are normal (Gaussian)).
Table 2 is based on such expansion factors.
The particular expansion factor used for the evaluation of the measurement uncertainty shall be stated.
NOTE: Information on uncertainty contributions, and verification procedures are detailed in TR 102 273 [8].
8 Methods of measurement and limits for transmitter
parameters
8.1 General
The radar level gauging applications covered by the present document use a stillpipe (a hollow waveguide) to convey
the radar signal to the liquid surface in the pipe and back again (see annex C). The system is functionally shielded by
the still pipe but due to the perforations necessary to make the liquid level inside the pipe exactly the same as that in the
tank, a small amount of RF leakage may unintentionally occur. The measurements described below aim to measure the
worst case of that RF leakage.
8.2 Permitted range of operating frequencies
8.2.1 Definition
The permitted range of operating frequencies is the frequency range over which the equipment is intended to operate.
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14 ETSI TS 102 692 V1.1.1 (2009-06)
8.2.2 Method of measurement
The minimum and maximum frequencies outside of the permitted range of frequencies of clause 8.2.3 shall be
measured using the radiated method shown in figure 1.

Measurement
distance r
Cable with
loss cl1
Measurement LNA
G
LNA
f
EUT
P
e.i.r.p
Measurement
antenna
Cable with
G
A
loss cl2
f [GHz]
p
m [dBm/MHz]
RBW: 1MHz
VBW: 3MHz
G : Gain of the measurement antenna
A
G : Gain of the measurement LNA [W]
LNA
g : Gain of Measurement LNA [dB]
LNA
Receiver
g : Gain of Measurement antenna [dBi]
A
cl1 and cl2: cable loss [dB] e.g. Spectrum analyser

Figure 1: Test set-up for measuring the operating frequency range
Conversion:
g = 20log()G
LNA LNA
g = 10log()G
A A
Cl
x
⎛ ⎞
⎜ ⎟
⎜ ⎟
⎝ ⎠
cl = 10
x
Equation (Values [dB]):
[dBm/MHz]
The values of the cable loss Cl1 and Cl2 are smaller than one. Consequently the logarithmic values cl1 and cl2 are
negative!
A test site selected from annex A (i.e. indoor test site or open area test site), which fulfils the requirements of the
specified frequency range and undisturbed lowest specified emission levels of this measurement shall be used.
The measurement procedure shall be as follows:
• place the spectrum analyser in video averaging mode and max hold mode with a minimum of 50 sweeps
selected and activate the transmitter with normal radar signal applied;
• find lowest frequency below the operating bandwidth at which spectral power density decreases to the level
given in clause 8.2.3. This frequency shall be recorded;
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15 ETSI TS 102 692 V1.1.1 (2009-06)
• find the highest frequency at which the spectral power density decreases to the level given in clause 8.2.3. This
frequency shall be recorded;
• the difference between the lowest frequency and highest frequency measured is the frequency range which
shall be recorded.
This measurement shall be repeated for each operating bandwidth as declared by the manufacturer.
The results obtained shall be compared to the limit in clause 8.2.3.
8.2.3 Limits Frequency range
The permitted range of operating frequencies for radiation is given in table 3. Outside the permitted range of operating
frequencies the emissions shall be reduced by no less than 10 dB.
Table 3: Frequency band of operation
Frequency band of operation
9 GHz to 10,6 GHz
8.3 Emissions
8.3.1 Definition
The total of emissions is the sum of wanted UWB emissions in the permitted frequency range of operation and outside
of the permitted frequency range of operation as well as the other emissions. Other emissions can occur inside as well as
outside of the frequency range of operation.
8.3.2 UWB emissions
UWB emissions are any UWB leakage signals from the still pipe perforations. The UWB emission limits are to be in
accordance with the Commission Decision 2007/131/EC [3] on UWB devices. The radar level gauges intended for the
use in above mentioned frequency range do not use the time domain UWB short pulses. Instead the radar level gauges
covered by the present document use the frequency domain FMCW and/or SFCW. Thus the frequency band generated
by the FMCW and/or SFCW radars is strictly controlled.
8.3.2.1 Method of measurement
Radiated measurements shall be performed according to the method using the measurement setup and test pipe as
described in annexes A and C.
Measurements shall be carried out over the frequency ranges as shown in clause 8.3.3.2, tables 5a, 5b and 6.
When measuring maximum mean power spectral density from the equipment under test, the spectrum analyser or
equivalent shall be configured as follows unless otherwise stated:
• Resolution bandwidth: 1 MHz.
NOTE 1: in order to obtain an adequate signal-to-noise ratio in the measurement system, radiated measurements
may have to be made using narrower resolution bandwidths where it is practical. In these cases, the
revised measurement configuration should be stated in the test report, together with calculations which
permit the measurements taken to be compared with the appropriate limits and an explanation of why
the signal levels involved necessitated measurement using the resolution bandwidth employed in order
to be accurately determined by the measurement equipment.
• Video bandwidth: Not less than the resolution bandwidth.
• Detector mode: RMS.
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16 ETSI TS 102 692 V1.1.1 (2009-06)
NOTE 2: RMS average measurements can be accomplished directly using a spectrum analyser which
incorporates an RMS detector. Alternatively, a true RMS level can be measured using a spectrum
analyser that does not incorporate an RMS detector (see ITU-R Recommendation SM.1754 [i.1] for
details).
• Average time (per point on spectrum analyser scan): 1 ms or less.
Frequency Span: Equal to or less than the number of displayed samples multiplied by the
resolution bandwidth. The measurement results shall be determined and recorded
over the frequency ranges as shown in clause 8.3.3.2, tables 5a, 5b and 6.
The measurements shall be repeated at the frequency band edges at 9 GHz and 10,6 GHz. The measurements at the
frequency band edges shall be performed at the frequency offsets as shown in table 4.
Table 4: Frequency offsets for band edge measurements
Band edge frequency Frequency with frequency
(GHz) offset applied
9 9 GHz to 20 MHz
10,6 10,6 GHz + 20 MHz
This frequency offset that is shown in table 4 is necessary since measurements at the exact frequency edges with a
spectrum analyser may integrate energy from both sides of the respective band edge frequency. This is caused by the
filter bandwidth of the test equipment. When measuring maximum peak power in the wanted frequency range from the
device under test, the spectrum analyser used should be configured as follows:
• Frequency: The measurement shall be centred on the frequency at which the maximum mean
power spectral density occurs.
• Resolution bandwidth: Equal or greater than 10 MHz but not greater than 50 MHz.
NOTE 3: For peak power measurements, the best signal to noise ratio is usually obtained with the widest available
resolution bandwidth.
• Video bandwidth: Not less than the resolution bandwidth.
• Detector mode: Peak.
• Display mode: Maximum Hold.
• Measurements shall be continued until the displayed trace no longer changes.
NOTE 4: To the extent practicable, the device under test is measured using a spectrum analyser configured using
the settings described above. However, in order to obtain an adequate signal-to-noise ratio in the
measurement system, radiated measurements may have to be made using narrower resolution bandwidths.
In these cases, the revised measurement configuration should be stated in the test report, together with
calculations which permit the measurements taken to be compared with the appropriate limits and an
explanation of why the signal levels involved necessitated measurement using the resolution bandwidth
employed in order to be accurately determined by the measurement equipment.
8.3.2.2 Limits
The maximum mean equivalent isotrop
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