RSS-212

Issue 1 (Provisional)
February 27, 1999

Spectrum Management and Telecommunications Policy

Radio Standards Specification

Test Facilities and Test Methods for

Radio Equipment

Aussi disponible en français - CNR-212

 Table of Contents

Page

1.0 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.0 Test Facilities for Radiation Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.1 Open Area Test Site (OATS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.1.1 Turntable and Test Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1.2 Filing of an Open Area Test Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 GTEM Enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3.0 Radiation Measurement Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2 Test Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3 Near-field Measurement Method Below 30 MHZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.0 Antenna Conducted Measurement Method (above 30 MHZ) . . . . . . . . . . . . . . 6

5.0 AC Wireline Conducted Measurement Method (450 kHz to 30 MHZ) . . . . . . . 6

Figure A - Circuit of a LISN Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

6.0 Inquiries about this Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 1 - Equipment Arrangement for Radiation Test Site . . . . . . . . . . . . . . . . . . . . . . . . . .11
Test Facilities and Test Methods for Radio Equipment RSS-212

1.0 Scope

This Radio Standards Specification (RSS) gives a brief description of suitable test facilities
and test methods for (1) field strength radiated measurement and (2) conducted
measurement of unwanted emissions into the AC Power Supply Network. Other test
methods conforming to good engineering principles may be acceptable to Industry Canada.
For example: ANSI C63.4-1992 “Method of Measurement of Radio Noise Emissions from
Low Voltage Electrical and Electronic Equipment in the Range of 9 kHz to 40 GHZ”,
published by the IEEE.

Specific test methods may also be given in the equipment RSSs, in which case they take
precedence.

2.0 Test Facilities for Radiation Measurements

2.1 Open Area Test Site (OATS)

The following is a brief description of a "3-metre Open Area Test Site" (OATS)
suitable for measurements in the frequency band 30 MHz to 1 GHz. Although the
OATS described herein is recognized for radiated measurement between 30 MHz and
1 GHz, pending the availability of a more accurate procedure from the international
electromagnetic compatibility (EMC) community, OATS is deemed adequate for
measurements up to 40 GHz.

Measurements using a calibrated site of greater dimensions are permitted, with the
field strength extrapolated to the specified distance of the technical standard using an
inverse linear distance extrapolation, i.e. 20 dB/decade of distance. For near-field
measurement frequencies below 30 MHz, see section 3.3.

Field strength measurements may also be performed at an alternate test site such as a
semi-anechoic chamber provided that is shown to be equivalent to an OATS.

Open area tests may be performed at the prevailing ambient temperature provided that
the prevailing temperature is within the design range for the equipment, and the
temperature noted and reported.

The OATS shall be an area clear of any obstructions such as trees, bushes or metal
fences for at least within an elliptical boundary of dimensions as shown in Figure 1(a).
Objects outside this boundary may still affect the measurements and care shall be taken
to choose a site as far as possible from large metallic objects of any sort, including
underground cables and metal pipes except as required for the tests.

The terrain shall be flat. Any conducting object inside the area of the ellipse shall be
limited to dimensions less than one tenth of a wavelength at the highest frequency of
measurement. A metal ground plane or wire mesh covering at least the area of the

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ellipse and keeping the same major and minor axes as indicated in Figure 1(a) is
required.

All precautions shall be taken to ensure that reflections from surrounding structures
are minimized. See Radio Standards Procedure 100 (RSP-100), Radio Equipment
Certification Procedure for the procedure on filing/registration of an “Open Area Test
Site”.

Weather protection enclosures may be constructed either partially or entirely over the
site. Fibreglass, plastics, treated wood or fabric are suitable materials for construction
of an enclosure.

2.1.1 Turntable and Test Platform

A turntable that is rotated by remote control (360 degrees) with a

non-conducting platform of height 80 cm shall be used for supporting the
equipment under test (EUT) so that radiated emissions from all sides can be
measured. The turntable should be flush with the ground plane and the table
itself should have a metal top. The turntable should have a central hole for
power supply cables.

2.1.2 Filing of an Open Area Test Site

If the measurement requires the use of an OATS or its equivalent, a description

of such a test site and associated test instruments shall be filed with Industry
Canada, in advance, and a file reference number obtained.
The following information on the OATS is required:

(a) Location of the site. Include dimensioned site plan and photographs of site.
(b) Description of the types of materials used in the construction of the
measurement antenna supporting structure and in the construction of the
ground plane. Provide photographs and dimensioned drawings.
(c) Description of the OATS compound. Give precautions taken to minimize
reflections from surrounding structures, buildings, and terrain.
(d) Details about the field strength meter (frequency range, last date of
calibration).
(e) Description in detail of the obtainment of the normalized site attenuation.
This attenuation measurement must be performed in accordance with
standards from national or international organizations. The normalized site
attenuation measurements shall be reported for both the horizontal and
vertical polarizations. ! Site attenuation is defined as the ratio of the
power input of a tuned antenna to that at the output of a similarly tuned
receiving antenna for specified polarization, distance between the antennas,

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and heights above a flat reflecting surface. This is a measure of the

transmission path loss between two antennas. The normalized site
attenuation (NSA) is simply the site attenuation divided by the antenna
factors of the radiating and receiving antennas (in power units, not in dB).
It should be noted that the NSA is only required from 30 MHz to 1 GHz,
although the site can be used for measurements up to 40 GHZ.

Organizations suitably equipped with OATS and appropriate test equipment to

perform tests for equipment certification purposes for the public and wishing to
be listed in the Department's List of measurement facilities may request to be
so listed by advising the Certification Section of the Department (see section
6.0)

The site filing shall be re-submitted at least every three years.

2.2 GTEM Enclosure

The gigahertz transversal electromagnetic (GTEM) technology has been available for
many years. Until recently, acceptable correlation data between them and Open Area
Test Sites has been lacking. Many technical papers have been presented at leading
EMC forums with good acceptance by the EMC community. Sufficient
documentation and operating characteristics are now known. Work is still continuing
evaluating the capabilities and limitations of GTEM technology on many international
fronts.

The use of a GTEM enclosure as an alternate test site has several benefits.
Measurements can be made much faster than on an open area test site. GTEM
enclosures are used indoors and thus are not subject to delays caused by weather.
GTEM enclosures lend themselves well to automated test methods thus reducing test
time and increasing repeatability.

Industry Canada will accept for equipment certification purposes, radiated emission
measurements taken using a GTEM enclosure under the following conditions:

(a) Emission measurements, correlated to an OATS, must be provided for each

general type of equipment (equipment of similar functionality and physical
configuration; e.g., hand held transmitter, laptop computer, etc.) for which GTEM
acceptance is sought. Acceptable correlation data must be submitted along with
the appropriate analysis that demonstrates equivalence with an open area test site.
The open area test site used for comparison must comply with the requirements of
this RSS. Validity of the calculated correlation coefficients must be supported by
statistical analysis.

(b) A reference number will be assigned to a GTEM facility that has successfully
demonstrated correlation to an OATS. Future certification submissions need only

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cite the GTEM reference number provided that the equipment meets the
functionality and physical configuration described in 2.2(a).

(c) In cases of disagreement, radiated emission tests performed at an open area test
site filed with Industry Canada will take precedence.

Measurements from other TEM enclosures will be considered on a case-by-case basis.

3.0 Radiation Measurement Methods

3.1 Accessories

Accessories and peripheral equipment that are normally required to be connected to

the device in actual use shall be so connected with representative cable lengths, and be
functioning for the tests.

The emission tests shall be performed with the device and accessories configured in a
manner which tends to produce the maximum level of emissions within the range of
variations that can be expected under normal operating conditions. Only one set of
tests using representative peripherals and accessories is required.

If the interconnecting cables are not supplied by the equipment manufacturer, cables
1.0 metre long and of similar construction with respect to shielding should be used.
Excess cables shall be folded back and forth to form a bundle 30 to 40 cm in length
and placed on the test platform. The bundle may also be hung over the edge of the
platform provided that it is kept at least 40 cm above the ground plane.

3.2 Test Method

The EUT shall be oriented in the manner in which it is designed to operate and placed
on the test platform; refer to Figure 1(b). The power supply and other external cables
(excluding the interconnecting cables) shall be fed through the hole in the centre of the
table.

The EUT antenna shall be extended fully and the EUT operated in its normal mode of
operation. The EUT's radiated spectrum shall be measured using a tuned dipole (or
other antenna of known characteristics herein referred to as the measurement antenna)
in the vertical plane of polarization.

The measurement antenna shall be located 3 metres (horizontal distance) from the
EUT antenna and it shall be mounted on a non-conducting mast that permits the
antenna height to be varied between 1.0 and 4.0 metres. The lower element of the
vertical dipole measurement antenna shall be kept at least 25 centimetres above the
ground plane for any measurement.

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The received signal shall be coupled to a spectrum analyser. The EUT shall be rotated
through a total of 360 degrees in azimuth and the height of the measurement antenna
varied between 1.0 and 4.0 metres to find the maximum field strength. Record the
frequency and the field strength.

The above test is to be repeated with the measurement antenna in the horizontal
polarization. The maximum field strength (FS) (vertical or horizontal polarization,
whichever value is greater) is to be used below.

For hand-held or body-worn devices, the device shall be tested in three orthogonal
planes: lying on its side, back and on its end. The maximum FS of the 3 positions is to
be used below.

The EUT shall be de-activated and the residual field strength due to the ambient radio
frequency (RF) noise measured. To ensure that the EUT field strength measurement is
not significantly influenced by ambient RF noise, the latter level shall be at least 6 dB
below that of the EUT signal.

The following formula may be used to convert the maximum field strength (FS) in
volts/metre to the EUT output power (TP) in watts:

TP = (FS x D)2
30 x G

where D is the distance in metres between the two antennas and G is the EUT antenna
numerical gain referenced to isotropic gain. (Note: In an open area test measurement
the effect due to the metal ground reflecting plane should be subtracted from the
maximum field strength value in order to reference it to free space, before calculating
TP).

3.3 Near-field Measurement Method Below 30 MHZ

For a radio signal for which the wavelength (8) is much greater than the largest
dimension of the aperture of the transmit antenna's dimension, the far-field distance
(dFF) is given by the formula, (where dFF and 8 are in metres):

dFF $ 8/(2B).

Conversely, near-field distance is much less than the above value with a transitional
zone.

When the measurement is in the near-field, a loop measurement antenna, and not a rod
or dipole, should be used. The field intensity meter (FIM) may be calibrated in
microamperes/metre or calibrated to read in microvolts/metre where E/H = 377 is used
in the conversion.

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Pending the development of a method for measurement below 30 MHz, the field
strength may be measured in its near field (measurement distance less than 8/(2B)).
The measured field strength may be extrapolated to any reference distance within the
near-field and transitional zones using the approximate formula: field strength varies as
the inverse distance square (40 dB per decade of distance).

Measurements at a minimum of two distances on at least one radial to determine the

proper extrapolation formula instead of 40 dB is also permitted.

The use of a ground plane (such as that used for an OATS) is not required for near-
field measurements.

Due to a large value for the standard deviation that can be expected in practice, near
field measurement is difficult.

4.0 Antenna Conducted Measurement Method (above 30 MHZ)

When the antenna is detachable, and where permitted by the relevant Radio Standards
Specification (RSS), the transmitter output power and the unwanted emissions may be
measured by replacing the antenna with a power meter or a spectrum analyser of resistance
equal to the impedance specified for the antenna. Alternatively, an impedance matching
network can be used with the network loss accounted for.

5.0 AC Wireline Conducted Measurement Method (450 kHz to 30 MHZ)

Alternating current (AC) wireline conducted emissions are unwanted radio frequency
currents induced in any AC conductor external to the equipment which could conduct
interference to other equipment via the AC electrical network. The description below is only
applicable to small devices, usually tabletop or wall-mounted equipment and not floor-
standing equipment.

If the EUT normally receives power via a battery charger, then it is the charger that is
required to have the AC wireline conducted measurement done.

Wherever possible this test should be done in a screened room with AC power outlets
equipped with RF filters.

Conducting Ground Plane: A ground plane or screen is required for power line
conducted measurements. This ground plane is to consist of a floor earth-grounded
conducting surface, which may be the metal floor of a shielded test chamber. The
conducting surface shall be at least 2x2 metres, and shall extend at least 0.5 metre beyond
the vertical projection (footprint) of the EUT. The ground plane shall be covered by
insulating materials between 3 mm and 12 mm thick.

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Vertical Conducting Plane: A vertical conducting plane or screen of at least 2x2 metres is
required. This vertical plane shall be electrically connected to the ground plane at intervals
no greater than 1 metre along its entire length.

Test Table or Platform: A non-conducting table of about 1.5x1.0 metres and height 80 cm
(tabletop to ground plane) is required to support the EUT. The rear of the tabletop shall be
40 cm removed from the vertical conducting surface.

LISN: A Line Impedance Stabilization Network (LISN) is required for the measurement of
unwanted emissions conducted into the power supply network. The purpose of the LISN is
to present a standard line impedance to the EUT regardless of local power line impedance
conditions. The LISN is an unbalanced Pi (B) filter, with L1 as a series inductor of
50 micro-henry (uH) of wire gauge sufficient to carry the full EUT AC current with less
than 2 volts drop.

An example of a 50 ohms/50 uH LISN, of 50 ohms impedance over the frequency range of

10 kHz to 30 MHz, is shown in Figure A. The equivalent impedance of this LISN circuit as
a function of the frequency is given in Table 1. A CISPR quasi-peak meter of minimum 9
kHz bandwidth and 50 ohms input impedance is to be connected across R1 for the
measurement. Each AC wire of the EUT, except the ground wire, shall have an LISN filter
connected in series (i.e. a LISN is also required on the neutral wire). For the LISN filter
not connected to the CISPR meter, a 50 ohms resistor shall be shunted across its R1.
Other equivalent LISNs of nominal 50 ohms impedance from 450 kHz to 30 MHz are also
permissible.

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Figure A - Circuit of a LISN Network

AC power AC
LISN same as below
input

AC
AC power L1 (50 uH)
input

C2 8 uF 0.25 uF C1 EUT

R1 CISPR
R2 5S 1000 S meter
(50 S)

Ground

Table 1

Impedance of the LISN Circuit Drawn on Figure A

(neglecting the effects of C1, C2 and R1)

Frequency Equivalent Impedance

(ohms)

10 kHz 5.36
20 kHz 7.25
40 kHz 11.99
50 kHz 14.41
100 kHz 25.11
200 kHz 37.74
500 kHz 47.21

1.0 MHz 49.26

2.0 MHz 49.80
5.0 MHz 49.98
8.0 MHz 50.00
30.0 MHz 50.00

Equipment Arrangement: The EUT shall be placed on the test table. The EUT shall be
kept at least 80 centimetres from any other earth-grounded conducting surface, LISNs
included.

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The LISN can be placed on top of or immediately beneath the ground plane and grounded
by a heavy conductor to the ground plane. LISNs cannot be placed under the table directly
underneath the EUT but moved sideways to be at least 80 cm from the EUT chassis.

Each EUT current-carrying power lead, except the ground lead, shall be individually
connected through an LISN, preferably through RF filters, to the AC power supply.
Non-EUT components that require electric power shall not be connected through the same
LISN as the EUT.

Power cords of the EUT with leads in excess of the 80 centimetres separating the EUT from
the LISN shall be folded back and forth (may be tied with a string) so as to form a bundle
not exceeding 40 centimetres in length. Power cords of equipment other than the EUT do
not require bundling and may be placed on the table, but never over an LISN.

Interconnecting cables that hang closer than 40 cm to the ground shall be folded back and
forth into a bundle, taped and left hanging approximately midway between the table and
ground plane.

The CISPR meter case shall be electrically bonded by a short heavy conductor to the ground
plane.

Measurement Procedure

The transmitter shall be operated at its maximum power output. For a transceiver, the
receiver conducted measurement can be tested at the same time as the transmitter.

The RF output voltage at each R1 port of the LISN mentioned above, i.e. each AC wire
(except the ground wire) of the EUT, shall be scanned from 450 kHz to 30 MHz, and the
noise frequencies and levels recorded.

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6.0 Inquiries about this Standard

Inquiries about this Standard should be directed to:

Manager, Certification
Engineering and Operations
Industry Canada
1241 Clyde Avenue
Ottawa, Ontario
Canada, K2C 1Y3
Tel: (613) 952-3200 / Fax: (613) 952-1088
Internet: certification.bureau@ic.gc.ca

Issued under the authority of the

Minister of Industry

R.W. McCaughern
Director General
Spectrum Engineering

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Fig. 1(a): Plan View

FIG. 1(b): Side View

D = 3 metres = distance between equipment under test (EUT) and field measurement antenna
X = 80 cm = height of turntable top above ground plane A
H = height of measurement antenna above ground plane A
B = auxiliary ground plane, when required

Figure 1: Equipment arrangement for radiation test site

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