Download TR41.7.3-01-02-003-SP-3210RV1d00(TIA631A),Mckinnon,AST

TR41.7.3-01-02-002
SP-3210RV1
Draft 00 – February 09, 2001
To be ANSI approved TIA/EIA-631-A
Telecommunications
Telephone Terminal Equipment
Radio Frequency Immunity Requirements
Formulated under the cognizance of TIA Subcommittee TR-41.7,
Environmental and Safety Considerations
With the approval of TIA Engineering Committee TR-41,
User Premises Telecommunications Equipment Requirements
FOREWORD
(This foreword is not part of this standard.)
This document is a TIA/EIA Telecommunications standard produced by Working Group TR-41.7.3
of Committee TR-41. This standard was developed in accordance with TIA/EIA procedural
guidelines, and represents the consensus position of the Working Group and its parent Subcommittee
TR-41.7, which served as the formulating group.
This standard is based on TIA/EIA-631-1996
The annexes in this Standard are informative and are not considered part of this Standard.
Suggestions for improvement of this standard are welcome. They should be sent to:
Telecommunications Industry Association
Engineering Department
Suite 300
250 Wilson Boulevard
Arlington, VA 22201
(To be published as TIA/EIA-631-A)
TR41.7.3-01-02-002
Draft 00
SP-3210RV1
The TR-41.7.3 Working Group acknowledges the contribution made by the following individuals in
the development of this standard.
Name
Representing
Position
(If Applicable)
Chair
Editor
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TR41.x.x Working Group Meeting Participants
(This list will be replaced in the Standard with a list of Contributors)
Working Group
Organization
Meetings Attended
Member
Represented
(C= Contribution, A= Attended Meeting)
Lucent Technologies
A
Al Martin
Raychem Tyco Electronics
A
Berndt Martenson
Ericsson L.M.
A
Chris Wellborn
Adtran Inc.
A
Curtis Domsch
Atlantic Scientific
A
Don McKinnon
AST Technology Labs
A
Don Murray
SBC
A
Dr Amar Ray
Sprint
A
George Boruowicz
Nortel Networks
A
James Brunssen
Telcordia Technologies
A
James Wiese
Adtran Inc.
A
Joe Murphy
Sprint LDD
A
Larry Payne
BellSouth
A
Larry Young
Qwest Communications
A
Percy Pool
Verizon
A
Phillip Havens
Teccor Electronics
A
Randy Ivans
UL Inc.
A
Ronald La
FCI Electrical Observer
A
Steve Whitesell
Vtech Innovations
A
Steven Bipes
Mobile Engineering
A
Thomas Croda
Sprint LDD
A
William Kammer
Siemens
A
Costa Mesa Feb,01
Savannah, Nov,00
?
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The Following Table Presents Contributions Related To This Standard:
(This table to be removed before publication)
Contributor
Organization
Contribution No.
Description
Don McKinnon
AST Tech Labs
TR41.7.3-01-02-001
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TABLE OF CONTENTS
1.
SCOPE _____________________________________________________________________ 1
2.
CATEGORIES OF CRITERIA ________________________________________________ 2
3.
NORMATIVE REFERENCES _________________________________________________ 3
4.
ABBREVIATIONS, ACRONYMS, AND DEFINITIONS ___________________________ 4
4.1.
4.2.
5.
ABBREVIATIONS AND ACRONYMS ...................................................................................... 4
DEFINITIONS ........................................................................................................................... 5
TECHNICAL REQUIREMENTS ______________________________________________ 6
5.1.
GENERAL INFORMATION ...................................................................................................... 6
5.1.1. Ambient Conditions ........................................................................................................... 6
5.1.2. EUT configuration and operating conditions .................................................................... 6
5.2. IMMUNITY TO RADIATED ELECTRIC FIELD (E-FIELD) INTERFERENCE ........................... 7
5.2.1. Receive (Near end interference) Requirements ................................................................. 7
5.2.2. Transmit (Far end interference) Requirements ................................................................. 7
5.2.3. Functionality Requirements ............................................................................................... 7
5.2.4. Method of Measurement .................................................................................................... 8
5.3. IMMUNITY TO CONDUCTED INTERFERENCE ON SIGNAL LEADS................................... 11
5.3.1. Receive (Near end interference) Requirements ............................................................... 11
5.3.2. Transmit (Far end interference) Requirements ............................................................... 11
5.3.3. Functionality Requirements............................................................................................. 11
5.3.4. Method of Measurement .................................................................................................. 12
5.4. IMMUNITY TO CONDUCTED INTERFERENCE ON POWER LEADS ................................... 16
5.4.1. Receive (Near end interference) Requirements ............................................................... 16
5.4.2. Transmit (Far end interference) Requirements ............................................................... 16
5.4.3. Functionality Requirements ............................................................................................. 16
5.4.4. Method of Measurement .................................................................................................. 17
6. ALTERNATIVE METHOD FOR DETERMINING IMMUNITY TO CONDUCTED RF
SIGNALS ON POWER AND SIGNAL LEADS ______________________________________ 20
7.
TEST EQUIPMENT ________________________________________________________ 21
7.1.
7.2.
TEM AND GTEM CELLS ...................................................................................................... 21
TEST EQUIPMENT LISTS ...................................................................................................... 22
7.2.1. Radiated Mode List of Equipment .................................................................................. 22
7.2.2. Conducted Signal Leads Mode List of Equipment .......................................................... 22
7.2.3. Conducted Power Leads Mode List of Equipment .......................................................... 22
7.2.4. Line Impedance Stabilization Network ........................................................................... 23
7.2.5. RF Signal Generating Equipment .................................................................................... 24
7.2.6. Selective voltmeter .......................................................................................................... 24
7.2.7. DC feed circuitry ............................................................................................................. 24
7.2.8. Voltage probe .................................................................................................................. 24
7.2.9. RF Voltmeter ................................................................................................................... 25
7.2.10. E-field probe ............................................................................................................... 25
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7.2.11.
7.2.12.
7.2.13.
8.
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Artificial Ear .............................................................................................................. 25
Acoustic Coupling Tube ............................................................................................ 25
Acoustic coupling tube calibration ............................................................................ 25
LABELLING ______________________________________________________________ 26
ANNEX A (INFORMATIVE) _____________________________________________________ 27
FUTURE CONSIDERATIONS ............................................................................................................ 27
ANNEX B (INFORMATIVE) _____________________________________________________ 28
ANNEX C (INFORMATIVE) _____________________________________________________ 30
CONSIDERATIONS ........................................................................................................................... 30
INFORMATIVE REFERENCES .......................................................................................................... 30
Table of Figures
Figure 1 – General TEM cell test setups for radiated E-field immunity................................................ 9
Figure 2 – Cordless Handset Detailed setup of EUT for radiated E-field immunity ........................... 10
Figure 3 – Corded Handset Detailed setup of EUT for radiated E-field immunity ............................. 10
Figure 4 – Test setup for conducted immunity on signal leads ............................................................ 13
Figure 5 – Physical arrangement of EUT ............................................................................................. 14
Figure 6 – Test setup for metallic conducted immunity on power leads ............................................. 18
Figure 7 – TEM cell test setup for conducted immunity ..................................................................... 20
Figure 8 – Two types of TEM cell ....................................................................................................... 21
Figure 9 – Circuit diagram of the FCC/ANSI LISN ............................................................................ 23
Figure 10 – Circuit diagram of the IEC T-LISN .................................................................................. 23
Table of Tables
Table 1 – Climatic Conditions During Testing ...................................................................................... 6
Table 2 – RF Signal Characteristics for Radiated Mode E-field ........................................................... 7
Table 3 – RF Signal Characteristics for Conducted Mode on Signal Leads ........................................ 11
Table 4 – RF Signal Characteristics for Conducted Mode on Power Leads........................................ 16
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SCOPE
This standard specifies Radio Frequency (RF) immunity performance criteria for two-wire Telephone
Terminal Equipment (TTE) having an acoustic output. Criteria are specified for immunity to
radiated RF signals over the frequency range from 150 kHz to 150 MHz and for immunity to
longitudinal (common mode) conducted RF signals over the frequency range from 150 kHz to 30
MHz. Criteria for immunity to metallic (differential) conducted RF signals on signal leads is not
covered in this document but is under consideration for future revisions. In addition to the
performance levels themselves, this standard includes recommended test procedures or references to
existing standards wherein such procedures will be found.
For the purposes of this document, the term "TTE" applies only to an electronic device that has a
wireline connection to the public telecommunication network. In addition, the compliance criteria
related to an acoustic output is only specified for the acoustic output from a handset receiver.
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CATEGORIES OF CRITERIA
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Recommended requirements are designated by the terms “should” and “should not”. These
requirements generally relate to compatibility or performance advantages towards which future
designs should strive.
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Permissive requirements are designated by the terms “may” and “may not”. These requirements
are used to indicate an action that is permitted within the limits of the standard.
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Advisory requirements are designated by the term “desirable”. Advisory criteria represent product
goals or are included in an effort to ensure universal product compatibility and may be used
instead of a Recommended requirement. Both a mandatory and an advisory level are specified
for the same criterion, the advisory level represents a goal currently identifiable as having
distinct compatibility or performance advantages toward whic3h future designs should strive.
Four types of requirements are specified in this standard; Mandatory, Recommended, Permissive and
Advisory:
1. Mandatory requirements are designated by the terms “shall” and “shall not”. These
requirements are used to indicate conformity in which no deviation is permitted.
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3.
NORMATIVE REFERENCES
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2. IEC 318, An artificial ear, of the wide band type, for the calibration of earphones used in
audiometry, First edition, 1970.
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3. IEC 801-6, Electromagnetic compatibility for electrical and electronic equipment.
Immunity to conducted radio frequency disturbances above 9 kHz, Draft 6, 1992.
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4. IEEE 269 - 1992, IEEE Standards methods for measuring transmission performance of analog
and digital telephone sets.
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5. TIA/EIA-470-A - 1987, Telephone instruments with loop signaling
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6. TIA/EIA-579 - 1991, Acoustic-to-digital and digital-to-acoustic transmission requirements for
ISDN terminals
The following standards contain provisions, which, through reference in this text, constitute
provisions of this Standard. At the time of publication, the editions indicated were valid. All
standards are subject to revision, and parties to agreements based on this Standard are encouraged to
investigate the possibility of applying the most recent editions of the standards indicated below.
ANSI and TIA maintain registers of currently valid national standards published by them.
1. ANSI C63.4-1992, American National Standard, Methods of Measurement of Radio-Noise
Emissions from Low-Voltage Electrical and Electronic Equipment in the Range of 9 kHz to 40
GHz.
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4. ABBREVIATIONS, ACRONYMS, AND DEFINITIONS
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4.1.
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AM
Amplitude Modulation
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ANSI
American National Standards Institute
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AWG
American Wire Gauge
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CISPR
International Special Committee on Radio Interference
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CO
Central Office
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E-field
Electric Field
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EIA
Electronic Industries Association
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EMC
Electro Magnetic Compatibility
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EUT
Equipment Under Test
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FCC
Federal Communications Commission
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GTEM
Gigahertz Transverse ElectroMagnetic
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IEC
International Electrotechnical Commission
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IEEE
Institute of Electrical and Electronics Engineers
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LISN
Line Impedance Stabilization Network
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RF
Radio Frequency
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RFI
Radio Frequency Interference
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TIA
Telecommunications Industry Association
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TEM
Transverse Electro Magnetic
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T-LISN
Telecommunications Line Impedance Stabilization Network
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TTE
Telephone Terminal Equipment
For the purpose of correct interpretation of this document, the following key technical terms and
abbreviations apply. Terms used in the document but not defined in this section shall be interpreted
according to their internationally accepted definition.
ABBREVIATIONS AND ACRONYMS
For the purposes of this Standard, the following abbreviations and acronyms apply.
For the purpose of correct interpretation of this document, the following key abbreviations apply.
T&R
Tip and Ring terminals or interface
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4.2.
DEFINITIONS
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Auxiliary equipment
Equipment not under test, but indispensable for setting up all
functions and assessing the correct performance or operation of the
equipment under test during its exposure to RF signals.
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Far end interference
Interference effects produced in the Equipment Under Test (EUT)
that manifest themselves in auxiliary equipment connected to signal
leads in the test setup.
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Ground plane
A conducting surface or plate used as the common reference point
for circuit or system.
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RF Immunity
The ability of equipment to meet the performance criteria specified
in this standard in the presence of RF signals.
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Line Impedance Stabilization Network (LISN)
A network inserted between the leads of the
EUT and auxiliary equipment to provide a specified impedance
through which RF signals may be injected into the EUT and which
prevents RF signals from reaching the auxiliary equipment. Two
types of LISN are specified in this standard: the FCC/ANSI LISN
for use on power leads and the IEC T-LISN for use on signal leads.
For the purposes of this Standard, the following definitions apply.
Off-Hook
Refers to the state of a particular CPE rather than the line state.
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Near end interference
Interference effects produced in the EUT that manifest themselves as
an acoustic output from the handset receiver.
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Radio Frequency Interference (RFI) Performance degradation, malfunction, or failure of
equipment due to the presence of RF signals.
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Signal leads
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Telephone Terminal Equipment (TTE)
An electronic device which has a wireline
connection to the public telecommunications network.
Used to describe any conductors carrying signals between
equipment. This includes the tip and ring conductors of balanced
twisted pair cables.
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5. TECHNICAL REQUIREMENTS
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5.1.
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5.1.1.
Ambient Conditions
In order to minimize the impact of environmental parameters on test results, the testing shall be
carried out under the ambient conditions described below:
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5.1.1.1. Climatic Conditions
The climatic conditions shall be within the ranges of Table 1:
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GENERAL INFORMATION
Testing shall be performed at 100 logarithmically spaced points per decade. Dwell time shall be a
minimum of 0.5 seconds or the minimum response time, whichever is longer.
The alternative test methods may be used provided correlation to the preferred method can be shown.
Ambient temperature:
10°C to 40°C
Relative humidity (RH):
20% < RH < 60%
Atmospheric pressure:
68 kPa to 106 kPa (680 to 1060 mbar)
Table 1 – Climatic Conditions During Testing
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5.1.1.2. Electromagnetic Conditions
The electromagnetic conditions of the laboratory shall not influence the test results.
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5.1.1.3. Acoustic Conditions
The acoustic conditions of the laboratory shall not influence the test results. Refer to standard IEEE
269-1992 for further information.
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5.1.2.
EUT configuration and operating conditions
5.1.2.1. EUT configuration
The EUT shall be configured for testing to simulate the real application as closely as possible.
Power and interconnecting cables shall be of the same types as supplied or recommended for use
with the equipment.
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5.1.2.2. EUT operating conditions
The EUT shall be operated normally in order to allow a correct evaluation of immunity.
Grounding practices shall be representative of those used in a real installation. The EUT shall be
grounded in accordance with the manufacturer’s requirements and conditions of intended use.
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5.2.
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IMMUNITY TO RADIATED ELECTRIC FIELD (E-FIELD) INTERFERENCE
When subjected to the radiated E-field characterized in Table 2, the system or subsystem shall meet
the requirements of sections 5.2.1, 5.2.2, 5.2.3 below.
Frequency:
150 kHz to 150 MHz
E-Field Strength, unmodulated:
3 Vrms/m
Modulation:
1 kHz sinusoidal wave, 80% AM
Table 2 – RF Signal Characteristics for Radiated Mode E-field
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Note: Cordless telephones are exempt from these requirements in their intended transmit
frequency band of operation and receive frequency band of operation.
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5.2.1.
Receive (Near end interference) Requirements
The demodulated acoustic output from the handset receiver of the EUT shall not exceed 55 dBSPL,
except in the frequency band from 500 kHz to 2 MHz where the demodulated acoustic output shall
not exceed 45 dBSPL, when measured at 1 kHz in all off-hook operating states that affect
compliance.
If the telephone is equipped with receive volume control, the control shall be set to produce
the nominal Receive Objective Loudness Rating (ROLR) specified in ANSI/TIA-470A for analog
TTE and ANSI/TIA-579 for digital TTE.
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5.2.2.
Transmit (Far end interference) Requirements
For analog equipment, the demodulated signal output measured on-hook and off-hook at the artificial
CO termination shall not exceed -55 dBV (1.77 mV), except in the frequency band from 500 kHz to
2 MHz where the demodulated signal output shall not exceed -65 dBV (0.56 mV), when measured at
1 kHz for all operating states that affect compliance.
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5.2.3.
Functionality Requirements
When evaluated at frequencies of 1, 10, 30, and 100 MHz, the EUT shall maintain basic functionality
of transmit, receive, address signaling, and alerting. The EUT shall also not change operating state.
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For digital equipment, the EUT is connected to a compatible digital telephone. The demodulated
acoustic output from the handset receiver of the compatible telephone shall comply with section
5.2.1.
It is desirable that equipment maintain full functionality of all features.
Note: The 100 MHz test frequency is only applicable for radiated E-field immunity testing.
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5.2.4.
Method of Measurement
To test the radiated E-field immunity of an EUT, the basic setup is shown in Figure 1 and Figure 2 or
Figure 3 below.
1. A predetermined E-field strength can be established in the TEM cell by controlling the output
voltage measured at the TEM cell termination. The E-field (V/m) generated is the voltage
between septum and the ground, divided by the septum-to-ground spacing expressed in meters.
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An E-field probe and field strength meter may be used as an alternative method for establishing the
E-field in the TEM cell. The E-field probe should be located in the top half of the TEM cell,
midway between the septum and the top of the cell. The probe and field strength meter allow the
magnitude of the E-field to be read directly in V/m.
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For a telephone set, an artificial ear is used together with a preamplifier, a filter, and a voltmeter to
determine the sound pressure produced in the telephone handset, due to audio rectification of the
applied E-field.
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Alternatively, an acoustic tube can be used to couple the output sound pressure signal out of the
TEM cell to a microphone. Then, through a similar network as is used for the artificial ear, the
sound pressure produced in the telephone handset, due to audio rectification of the applied Efield can be measured.
Telephone base units shall be placed 10 cm above the bottom of the TEM cell. The signal leads shall
also be kept, as much as possible, 10 cm above the bottom of the TEM cell.
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The handset on corded telephones shall be supported in such a manner as to allow the handset cord to
rise 20 cm above the 10 cm reference plane (i.e., 30 cm above the bottom of the TEM cell). The
separation between the handset and the base unit shall be 30 cm. All excess cord length shall be
arranged in a serpentine, non-inductive manner 10 cm above the bottom of the TEM cell. See
figure 8b.
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The antenna on cordless base units shall be oriented vertically and extended such that the end of the
antenna is 20 cm above the 10 cm reference plane (i.e., 30 cm above the bottom of the TEM cell)
or to its maximum height, whichever is greater. The cordless handset shall be placed 10 cm
away from the base unit and canted away from it. The antenna shall be extended maximally or to
make a total length (handset and antenna) of 30 cm, whichever is less. See figure 8a.
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If a GTEM cell is used instead of a TEM cell, the E-field strength shall be determined by measuring
the input voltage applied to the septum and dividing by the septum to cell bottom spacing
determined at the location of the EUT. The alternative method of using an E-field probe in the
top half of the cell to measure the field strength cannot be used directly in a GTEM cell because
the field strength in the top half of the cell is not the same as in the bottom half due to the offcenter location of the septum. Depending on the size of the GTEM cell, the reference plane on
which the EUT is placed may need to be elevated more than 10 cm above the cell bottom to keep
the EUT in the middle 1/3 of the septum to cell bottom spacing. All other dimensions relative to
the placement of the handset, draping of the handset cord, etc. shall be the same as specified for
measurements in a TEM cell.
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General Precautions
1. Precautions should be taken to eliminate unwanted interference generated by the spurious
response of the signal sources (e.g., harmonics being detected by the receiver of cordless
telephones).
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Methods used to demonstrate the functionality of EUT during radiated immunity testing should not
disturb the radiated field.
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Figure 1 – General TEM cell test setups for radiated E-field immunity
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10 cm
Base Unit Antenna
Base Unit
Handset Antenna
20 cm
Signal and
Power Cables
Handset
10 cm
(not to scale)
Ground Plane
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Figure 2 – Cordless Handset Detailed setup of EUT for radiated E-field immunity
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Cordless Handset
Handset
30 cm
Acoustic Tube
or Arti¼cial Ear
Base Unit
20 cm
Signal and
Power Cables
10 cm
(not to scale)
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Ground Plane
Figure 3 – Corded Handset Detailed setup of EUT for radiated E-field immunity
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IMMUNITY TO CONDUCTED INTERFERENCE ON SIGNAL LEADS
When the Signal Leads are subjected to the conducted RF signal characterized in Table 3, the system
or subsystem shall meet the requirements of sections 5.3.1, 5.3.2, 5.3.3 below.
Frequency:
150 kHz to 30 MHz
E-Field Strength, unmodulated:
3 Vrms
Modulation:
1 kHz sinusoidal wave, 80% AM
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Table 3 – RF Signal Characteristics for Conducted Mode on Signal Leads
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5.3.1.
Receive (Near end interference) Requirements
The demodulated acoustic output from the handset receiver of the EUT shall not exceed 55 dBSPL,
except in the frequency band from 500 kHz to 2 MHz where the demodulated acoustic output shall
not exceed 45 dBSPL, when measured at 1 kHz in all off-hook operating states that affect
compliance.
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5.3.2.
Transmit (Far end interference) Requirements
For analog equipment, the demodulated signal output measured on-hook and off-hook at the artificial
CO termination shall not exceed -55 dBV (1.77 mV), except in the frequency band from 500 kHz to
2 MHz where the demodulated signal output shall not exceed -65 dBV (0.56 mV), when measured at
1 kHz for all operating states that affect compliance.
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5.3.3.
Functionality Requirements
When evaluated at frequencies of 1, 10, and 30 MHz, the EUT shall maintain basic functionality of
transmit, receive, address signaling, and alerting. The EUT shall also not change operating state.
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If the telephone is equipped with receive volume control, the control shall be set to produce the
nominal Receive Objective Loudness Rating (ROLR) specified in ANSI/TIA-470A for analog TTE
and ANSI/TIA-579 for digital TTE.
For digital equipment, the EUT is connected to a compatible digital telephone. The demodulated
acoustic output from the handset receiver of the compatible telephone shall comply with section
5.3.1.
Note - It is desirable that equipment maintain full functionality of all features.
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5.3.4.
Method of Measurement
This test method is designed for telecommunications signal leads of a system or subsystem which in
practice are of much greater length than the shorter runs (for example, 1 m to 2 m) that may be
illuminated in the radiated test. In addition, the test method is also intended to simulate potential
differences that may exist between grounding nodes of a system installation. The test level is
applicable to both the longitudinal and the metallic modes of interference injection as follows:
1. Longitudinal (common) mode interference shall be applied individually to balanced
telecommunications tip and ring leads of the system or subsystem.
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Metallic (differential) mode interference is not addressed in this document but is under consideration.
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Combined signal and power leads, using ordinary telephone pairs, are to be treated as signal leads.
The test set-up shall provide a means of feeding power without adversely affecting the signal.
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Note - TTE that exhibits acceptable immunity to longitudinal mode RF signals may continue
to be affected by metallic mode RF signals. To fully characterize TTE RF immunity, it
is desirable that tests be performed in both longitudinal and metallic modes.
277
278
279
280
281
282
283
284
285
286
287
288
5.3.4.1. Test Procedures
The test set-up shall be as shown in Figure 4. This figure is the conducted RF signal injection test
setup for the general case, involving signal leads. Corded EUTs shall be set-up as shown in Figure 5.
Cordless EUTs shall be set-up as shown in Figure 2.
Alternative test equipment may be used in which the open circuit voltage, source impedance, and
short-circuit current characteristics of the voltage injection generator can be shown to conform to the
requirement of immunity to conducted interference on signal leads (refer to section 5.3).
Measurement shall be performed 10 cm over a ground plane consisting of a copper or brass solid
plate, with the following dimensions:

Minimum thickness of 0.25 mm for copper, and 0.63 mm for brass.
289

Minimum surface area of 2.25 m2.
290

Minimum length of 1 m on the shorter side.
291
292
293
294
295
296
When testing is performed in a shielded enclosure, the ground plane shall be bonded to the shielded
enclosure so that direct current bonding resistance does not exceed 2.5 mΩ. The distance between
adjacent bonds shall not exceed 900 mm.
The distance between the EUT and any vertical metallic surface shall not be less than 40 cm.
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TR41.7.3-01-02-002
Draft 00
297
298
299
Figure 4 – Test setup for conducted immunity on signal leads
300
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(To be published as TIA/EIA-631-A
Acoustic
Tube
30 cm
Base Unit
Handset
Signal and
Power Cables
10 cm
Ground Plane
301
302
303
Figure 5 – Physical arrangement of EUT
304
305
306
307
1. When testing is performed outside of a shielded enclosure, the ground plane shall be grounded to
the safety ground of the mains supply which powers the test equipment used in the tests. A
number 6 AWG copper conductor is suggested. Connection practice shall comply with local
electrical utility safety regulations.
308
309
310
2. The base unit shall be set-up and oriented as it is intended to be installed. The handset, handset
cord, test leads and EUT leads shall be kept 10 cm above the ground plane. Any excess handset
cord length shall be arranged in a serpentine, non-inductive manner.
311
312
313
314
315
316
3. The RF signal levels to be used during this test are specified in section 5.3. The levels given
apply to the unmodulated RF carrier at each test frequency (see section 5.1). Once the desired
level of the carrier signal is established at a given frequency, it shall be 80% amplitude
modulated with a 1 kHz sine wave while checking the EUT for immunity. The process of
conducting a frequency sweep of the modulated signal while maintaining the desired level of the
unmodulated carrier shall be achieved in one of the following ways:
317
318
319
320
321

With the modulation turned off, adjust the RF signal source to produce the desired signal
level as measured by the RF voltmeter at the input of the appropriate LISN. Turn on the
80% AM, 1 kHz modulation and monitor the EUT for compliance with the criteria
specified in section 5.3. Then turn the modulation off, change to the next frequency, and
repeat the process.
322
323
324
325
326
327

With the modulation turned off, adjust the RF signal source to produce the desired signal
level as measured by the RF voltmeter at the input of the appropriate LISN. Turn on the
80% AM, 1 kHz modulation and observe the new reading of the RF voltmeter. It should be
approximately 1.15 times the previous reading, or 1.2 dB higher (see notes 1 & 2). Sweep
through the desired frequency range while maintaining this higher RF voltmeter reading
and monitoring the EUT for compliance with the criteria specified in section 5.3
328
Note 1: This difference in readings applies for a true RMS RF voltmeter.
329
330
331
332
Note 2: Checks should be made at various frequencies to ensure that the difference in RF
voltmeter readings for the modulated and unmodulated signals remains constant over
the specified frequency range.
14
333
334
335
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Draft 00
SP-3210RV1
TR41.7.3-01-02-002
The point of measurement of the injected voltage shall be at the output of the 6 dB attenuator as
shown in Figure 4. All leads shall be elevated, as much as possible, above the ground plane at a
constant height of 10 cm to render transmission line effects more repeatable.
336
337
The maximum length of the RF voltage sensing leads is 300 mm. This length is measured from the
EUT to the high impedance probe used.
338
339
340
341
342
5.3.4.2. Precautions
Precautions shall be taken to conform with government regulations regarding unlicensed
transmission of radio-frequency energy.
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343
344
345
346
5.4.
Draft 00
(To be published as TIA/EIA-631-A
IMMUNITY TO CONDUCTED INTERFERENCE ON POWER LEADS
When the Neutral and Hot Power Leads are each subjected to the RF signal characterized in Table 4,
the system or subsystem shall meet the requirements of sections 5.4.1, 5.4.2, 5.4.3 below.
Frequency:
150 kHz to 30 MHz
E-Field Strength, unmodulated:
3 Vrms
Modulation:
1 kHz sinusoidal wave, 80% AM
Table 4 – RF Signal Characteristics for Conducted Mode on Power Leads
347
348
349
350
351
352
353
354
355
356
357
358
5.4.1.
Receive (Near end interference) Requirements
The demodulated acoustic output from the handset receiver of the EUT shall not exceed 55 dBSPL,
except in the frequency band from 500 kHz to 2 MHz where the demodulated acoustic output shall
not exceed 45 dBSPL, when measured at 1 kHz in all off-hook operating states that affect
compliance.
359
360
361
362
363
364
365
366
367
368
5.4.2.
Transmit (Far end interference) Requirements
For analog equipment, the demodulated signal output measured on-hook and off-hook at the artificial
CO termination shall not exceed -55 dBV (1.77 mV), except in the frequency band from 500 kHz to
2 MHz where the demodulated signal output shall not exceed -65 dBV (0.56 mV), when measured at
1 kHz for all operating states that affect compliance.
369
370
371
372
373
374
375
376
5.4.3.
If the telephone is equipped with receive volume control, the control shall be set to produce the
nominal Receive Objective Loudness Rating (ROLR) specified in ANSI/TIA-470A for analog TTE
and ANSI/TIA-579 for digital TTE.
For digital equipment, the EUT is connected to a compatible digital telephone. The demodulated
acoustic output from the handset receiver of the compatible telephone shall comply with subclause
5.4.1.
Functionality Requirements
When evaluated at frequencies of 1, 10, and 30 MHz, the EUT shall maintain basic
functionality of transmit, receive, address signaling, and alerting. The EUT shall also not change
operating state.
It is desirable that equipment maintain full functionality of all features.
16
377
378
379
380
381
382
383
384
(To be published as TIA/EIA-631-A)
Draft 00
SP-3210RV1
TR41.7.3-01-02-002
5.4.4.
Method of Measurement
The test method is designed for those power leads of a system or subsystem which in practice are of
much greater length than the shorter runs (for example, 1 m to 2 m) that may be illuminated in the
radiated test. In addition, the test method is also intended to simulate potential differences that may
exist between grounding nodes of a system installation. The test level is applicable to both the
longitudinal and the metallic modes of interference injection as follows:
1. Power leads Metallic mode interference shall be applied to all ungrounded power conductors of
the system one conductor at a time.
385
386
387
Combined signal and power leads which combine both signal and power, such as ordinary telephone
pairs, are to be treated as signal leads. The test set-up shall provide a means of feeding power
without adversely affecting the signal.
388
389
390
391
The test level within the 150 kHz to 30 MHz band shall be in accordance with the requirements given
in subclause 5.4. Each of the above modes shall be tested independently.
392
393
394
395
396
397
398
399
400
401
402
403
5.4.4.1. Test Procedures
The test set-up shall be as shown in Figure 6. This figure is the conducted RF signal injection test
setups for the general case, involving power leads. Corded EUTs shall be set-up as shown in Figure
5. Cordless EUTs shall be set-up as shown in Figure 2.
Alternative test equipment may be used in which the open circuit voltage, source impedance, and
short-circuit current characteristics of the voltage injection generator can be shown to conform to the
requirement of immunity to conducted interference on power leads (refer to section 5.4).
Measurement shall be performed 10 cm over a ground plane consisting of a copper or brass solid
plate, with the following dimensions:

Minimum thickness of 0.25 mm for copper, and 0.63 mm for brass.
404

Minimum surface area of 2.25 m2.
405

Minimum length of 1 m on the shorter side.
406
407
408
409
410
411
412
When testing is performed in a shielded enclosure, the ground plane shall be bonded to the shielded
enclosure so that direct current bonding resistance does not exceed 2.5 mΩ. The distance between
adjacent bonds shall not exceed 900 mm.
The distance between the EUT and any vertical metallic surface shall not be less than 40 cm.
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TR41.7.3-01-02-002
Draft 00
(To be published as TIA/EIA-631-A
413
414
Figure 6 – Test setup for metallic conducted immunity on power leads
415
416
417
418
419
1. When testing is performed outside of a shielded enclosure, the ground plane shall be grounded to
the safety ground of the mains supply which powers the test equipment used in the tests. A
number 6 AWG copper conductor is suggested. Connection practice shall comply with local
electrical utility safety regulations.
420
421
422
2. The base unit shall be set-up and oriented as it is intended to be installed. The handset, handset
cord, test leads and EUT leads shall be kept 10 cm above the ground plane. Any excess handset
cord length shall be arranged in a serpentine, non-inductive manner.
423
424
425
426
427
428
3. The RF signal levels to be used during this test are specified in section 5.3. The levels given
apply to the unmodulated RF carrier at each test frequency (see section 5.1). Once the desired
level of the carrier signal is established at a given frequency, it shall be 80% amplitude
modulated with a 1 kHz sine wave while checking the EUT for immunity. The process of
conducting a frequency sweep of the modulated signal while maintaining the desired level of the
unmodulated carrier shall be achieved in one of the following ways:
18
429
430
431
432
433
(To be published as TIA/EIA-631-A)
Draft 00
SP-3210RV1
TR41.7.3-01-02-002

With the modulation turned off, adjust the RF signal source to produce the desired signal
level as measured by the RF voltmeter at the input of the appropriate LISN. Turn on the
80% AM, 1 kHz modulation and monitor the EUT for compliance with the criteria
specified in section 5.3. Then turn the modulation off, change to the next frequency, and
repeat the process.
434
435
436
437
438
439

440
Note 1: This difference in readings applies for a true RMS RF voltmeter.
441
442
443
444
445
446
447
Note 2: Checks should be made at various frequencies to ensure that the difference in RF
voltmeter readings for the modulated and unmodulated signals remains constant over
the specified frequency range.
The point of measurement of the injected voltage shall be at the output of the 6 dB attenuator as
shown in Figure 4. All leads shall be elevated, as much as possible, above the ground plane at a
constant height of 10 cm to render transmission line effects more repeatable.
448
449
The maximum length of the RF voltage sensing leads is 300 mm. This length is measured from the
EUT to the high impedance probe used.
With the modulation turned off, adjust the RF signal source to produce the desired signal
level as measured by the RF voltmeter at the input of the appropriate LISN. Turn on the
80% AM, 1 kHz modulation and observe the new reading of the RF voltmeter. It should be
approximately 1.15 times the previous reading, or 1.2 dB higher (see notes 1 & 2). Sweep
through the desired frequency range while maintaining this higher RF voltmeter reading
and monitoring the EUT for compliance with the criteria specified in section 5.3
450
451
452
453
454
5.4.4.2. General precautions
Apply caution when performing conducted immunity testing on power leads in order not to damage
high-impedance voltage probes.
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TR41.7.3-01-02-002
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
6.
Draft 00
(To be published as TIA/EIA-631-A
ALTERNATIVE METHOD FOR DETERMINING IMMUNITY TO CONDUCTED
RF SIGNALS ON POWER AND SIGNAL LEADS
To test the conducted immunity of an EUT, the basic set-up for telephone terminal equipment with
handsets is shown in Figure 4, Figure 5, Figure 6, and Figure 7.
The signal generator shall be 80% amplitude modulated with a 1kHz sine wave. By adjusting the
power level of the amplitude modulated generator, a predetermined interference signal can be
injected into the cables of the EUT.
Detailed test procedures are similar to those given in
subclause6.5.2.4.
The telephone base unit and handset shall be centrally located between the sides, 10 cm above the
bottom of the TEM cell (which serves as the ground plane), and separated from each other by 30 cm.
All excess cord length shall be arranged in a serpentine, non-inductive manner 10 cm above the
bottom of the TEM cell.
The response may be monitored by an artificial ear which is connected to a multimeter through a
preamplifier and a filter.
Alternatively, an acoustic tube can be used to couple the output sound pressure signal out of the
TEM cell to a microphone. Then through a similar network as is used for the artificial ear, the sound
pressure produced in the telephone handset, due to audio rectification of the conducted interference,
can be measured.
50 ohms
50 ohms
Artificial ear
EUT
0.3 m maximum
Preamplifier
10cm
Acoustic Tube
Microphone
T-LISN
Artificial C.O.
Alternate
Test Methods
0.1 m maximum
Signal generator
and
power amplifier
V
6 dB pad
Selective
Voltmeter
478
479
Figure 7 – TEM cell test setup for conducted immunity
480
20
(To be published as TIA/EIA-631-A)
TR41.7.3-01-02-002
481
7.
482
483
484
485
486
487
488
489
490
491
492
493
494
7.1.
Draft 00
TEST EQUIPMENT
TEM AND GTEM CELLS
The useful frequency range of a TEM cell depends on its physical shape and dimensions. For a
symmetrical TEM cell (Figure 8a), an important parameter is the distance d between the septum and
the bottom internal wall of the cell. For a TEM cell with d equal to 0.592 m, the operating frequency
range is from DC to 150 MHz. A larger TEM cell will have a lower high frequency limit and will
not cover the frequency range required by subclause 5.2. Smaller TEM cells with higher cut-off
frequencies are not practical for large EUTs, since the EUT should be confined to the middle 1/3 of
the distance between the septum and the bottom of the cell for maximum uniformity of the E-field.
For a tapered GTEM cell (Figure 8b), the upper frequency limit is not dependent on d and extends to
several GHz. The restriction that the EUT be confined to the middle 1/3 of the septum to cell bottom
distance for maximum uniformity of the E-field still applies, but does not limit the size of the EUT
that can be tested provided a large enough GTEM cell is available.
495
496
SP-3210RV1
Figure 8 – Two types of TEM cell
497
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TR41.7.3-01-02-002
498
499
7.2.
500
501
7.2.1.
Draft 00
(To be published as TIA/EIA-631-A
TEST EQUIPMENT LISTS
The follow is a list of test equipment that may be used for RFI testing.

Radiated Mode List of Equipment
TEM or GTEM cell
502

Artificial Ear or Acoustic Tube
503

IEC T-LISN and FCC/ANSI LISN
504

Signal Generator with amplitude modulation capability and power amplifier
505

Preamplifier
506

Selective Voltmeter
507

Multi-meter
508

RF voltmeter and probe
509

E-field probe

Conducted Signal Leads Mode List of Equipment
Ground Plane
512

Artificial ear or acoustic tube
513

IEC T-LISN and FCC/ANSI LISN
514

Signal generator with amplitude modulation capability and power amplifier
515

Preamplifier
516

Selective voltmeter
517

DC Feed circuitry
518

RF Voltmeter and Probe

Conducted Power Leads Mode List of Equipment
Ground Plane
521

Artificial ear or acoustic tube
522

IEC T-LISN and FCC/ANSI LISN
523

Signal generator with amplitude modulation capability and power amplifier
524

Preamplifier
525

Selective voltmeter
526

DC Feed circuitry
527

RF Voltmeter and Probe
510
511
519
520
7.2.2.
7.2.3.
528
22
529
530
531
532
(To be published as TIA/EIA-631-A)
Draft 00
SP-3210RV1
TR41.7.3-01-02-002
7.2.4.
Line Impedance Stabilization Network
A Line Impedance Stabilization Network (LISN) is needed for conducted immunity measurements.
In general, the LISN housing and the ground plane shall be electrically bonded together in such a
manner that they are kept at the same RF potential.
533
534
535
536
7.2.4.1. FCC/ANSI LISN
The FCC/ANSI LISN (ANSI C63.4-1992), applicable for the frequency band from 150 kHz to 30
MHz, is to be used with the power leads of the equipment under test. The circuit shown in figure 1
shall be used over the entire frequency band from 150 kHz to 30 MHz.
537
538
Figure 9 – Circuit diagram of the FCC/ANSI LISN
539
540
541
542
543
7.2.4.2. IEC T-LISN
The IEC T-LISN (draft IEC 801-6 -1992), applicable for the frequency band from 150 kHz to 30
MHz, is to be used with the signal leads of the EUT. The electrical network of the IEC T-LISN is
shown in figure 2. Note that R2 can be removed and the terminal can be used as an input port for
injection of the RF signal (for example, 80% AM signal) into the signal leads of an EUT.
544
Note - CISPR committee G is presently considering changes to the T-LISN.
545
546
Figure 10 – Circuit diagram of the IEC T-LISN
547
23
548
549
SP-3210RV1
Draft 00
TR41.7.3-01-02-002
The electrical characteristics of the T-LISN are as follows:
1. Common mode impedance:
550

150 ±20 Ω
551

Phase angle ±20°
552
Longitudinal conversion loss:
553

Better than 65 dB at 150 kHz
554

Better than 50 dB at 1 MHz
555

Better than 35 dB at 10 MHz
556
557
558
Isolation between the EUT port and the auxiliary equipment port shall be:

At least 25 dB.
Insertion loss is defined in relation to the differential mode impedance as follows:
559

Less than 1.0 dB for 100 Ω
560

Less than 1.5 dB for 150 Ω
561

Less than 2.0 dB for 600 Ω
562
563
564
565
566
567
568
(To be published as TIA/EIA-631-A
7.2.5.
RF Signal Generating Equipment
Any commercially available signal source, power amplifiers, power oscillators, and general purpose
amplifiers capable of developing the required RF signal test levels, may be used, provided the
following requirements are met:

Frequency accuracy shall be within ±2%.

Harmonics and spurious output (that is, harmonic contents) shall not exceed a level of 30
dB below the power of the fundamental.
569
570
571
572
573
574
575
The power amplifier should be able to provide a power level of the order of 10 W or more for a
typical immunity threshold level. The injection process depends on the efficiency of the T-LISN and
the attenuator used to stabilize the operation of the power amplifier.
576
577
578
7.2.6.
Selective voltmeter
A selective voltmeter may be used for the immunity tests of telephone sets. It shall have adequate
sensitivity for the frequency band of interest.
579
580
581
582
7.2.7.
DC feed circuitry
The DC feed current generated by the artificial CO for the EUT is adjusted to give 50 mA by varying
the resistance or battery voltage. The test circuit identified as the "Balanced Minimal Loss Feed
Circuit" in IEEE 269-1992 shall be used.
583
584
585
586
7.2.8.
Voltage probe
The voltage probe's input impedance shall be greater than or equal to 1 MΩ shunted by a capacitor of
3 pF.
The RF signal generating equipment should have a 50 Ω output impedance and be capable of
delivering the required interference voltage within the frequency band 150 kHz to 150 MHz. The RF
signal shall be a carrier 80% amplitude modulated with a 1 kHz sine wave.
24
587
588
589
590
591
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Draft 00
SP-3210RV1
TR41.7.3-01-02-002
7.2.9.
RF Voltmeter
A RF voltmeter and associated probe having a combined minimum sensitivity of 0.1 V and a
minimum input impedance of 5 kΩ over the frequency range from 150 kHz to 150 MHz is necessary
for measuring the RF signal level injected into the LISN for conducted immunity measurements and
the signal level provided to the TEM or GTEM cell for radiated immunity measurements.
592
593
594
595
7.2.10. E-field probe
An E-field probe and associated metering unit having a minimum sensitivity of 0.3 V/m over the
frequency range from 150 kHz to 150 MHz may be used for measuring the field strength in a TEM or
GTEM cell.
596
597
598
599
7.2.11. Artificial Ear
Measurements of the acoustic output produced by the receiver of the EUT should be made using an
artificial ear corresponding to the IEC-318 coupler for supra-aural earphones. The acoustic output of
telephone receivers shall be measured using the methods of IEEE 269-1992.
600
601
602
603
604
Note: Capacitive coupling to the metallic structure of commercial implementations of this
artificial ear may have undesirable effects on measurement results for certain types of
telephones, particularly dial-in-handset telephones that contain a large amount of
circuitry in the handset. In this case, the use of the acoustic coupling tube described in
subclause 7.2.12 may be desirable.
605
606
607
608
609
610
611
612
613
614
7.2.12. Acoustic Coupling Tube
In order to avoid the effects of capacitive coupling to the metallic structure of an artificial ear or its
disturbing effects on the E-field, it may be desirable to use an acoustic coupling tube instead of the
artificial ear to measure the output of the telephone receiver. The length of such an acoustic coupling
tube should be an integral number of wavelengths of the demodulated 1000 Hz signal to be measured
(i.e., N x 0.345 m for typical laboratory conditions). The tube should be terminated at the handset
with a non-conductive coupler having external dimensions matching that of the artificial ear. The
tube should be made of a flexible, thick-walled, non-conductive material. The inner diameter of the
tube should provide a snug fit around the microphone and preamplifier assembly that may be
removed from the artificial ear defined in subclause 7.2.11.
615
616
617
618
619
620
621
7.2.13. Acoustic coupling tube calibration
The acoustic coupling tube shall be calibrated as follows:
1. Apply a 1000 Hz signal to the EUT and measure its acoustic output on the artificial ear using the
procedure for receive measurements described in IEEE 269-1992. The level of the drive signal is
not critical, but it should produce a sound pressure level in the artificial ear in the expected range
of measurement (i.e., on the order of 45 to 94 dBSPL). Note the drive level used and the sound
pressure level produced.
622
623
624
Using the identical test signal and other details of the test set-up (e.g., battery feed circuitry) as in
step 1, measure the output voltage from the microphone terminating the acoustic coupling tube.
Adjust the indicating instrument to read the same sound pressure as measured in step 1.
625
626
627
628
629
Note: This calibration is specific to the telephone being measured. Similar telephones using
the same handset style and type of receiver element will produce similar calibrations.
However, changing from one type of receiver element to another (e.g., from a moving
coil to a piezo ceramic receiver) may give substantially different results and requires a
recalibration for the new receiver type.
25
SP-3210RV1
TR41.7.3-01-02-002
630
631
632
633
634
635
636
637
638
639
8.
Draft 00
(To be published as TIA/EIA-631-A
LABELLING
Manufacturers may wish to identify TTE that has been demonstrated to comply with this standard by
placing a label on the equipment. To provide consistency of information to the user, the following
statement should be used for the label:
This device complies with ANSI/TIA/EIA - 631 for immunity to radio frequency interference.
This statement may also be used on the equipment packaging and in other information provided to
the user.
26
(To be published as TIA/EIA-631-A)
TR41.7.3-01-02-002
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
ANNEX A (INFORMATIVE)
667
668
669
FUTURE CONSIDERATIONS
Draft 00
SP-3210RV1
This standard is one of a series of technical standards on telecommunications terminal equipment
prepared by TIA Engineering Committee TR-41. It will be useful to anyone engaged in the
manufacturing of telecommunications terminal equipment and to those purchasing, operating, or
using such equipment or devices.
Many electronic consumer products in the marketplace employ circuitry that generates radio
frequency (RF) energy, even though the given product is not intended to radiate a signal outside its
plastic or metal enclosure. Radio receivers (AM and FM), stereo music players, TV sets and
telephone sets are examples of such products. At the same time, some of these products
unintentionally demodulate radio signals from other devices or radio/TV transmitters and cause user
annoyance due to the interfering signals that can often be heard in telephone handset receivers, audio
amplifiers or seen on the TV screen.
The major increase in the number of interference complaints in recent years caused the FCC to seek
industry assistance in developing programs to minimize product susceptibility to extraneous radio
signals. The purpose of this standard is to provide requirements for the immunity of telephone
terminal equipment to RF signals. Compliance with these requirements will permit a product to
function normally in the majority of locations where it is used.
It is important to note that the mitigation of RF susceptibility problems in products is much easier to
accomplish in the product design stage rather than after it is sold and in the user's hands. In fact,
some products cannot be successfully modified in the field to mitigate interference problems.
The RF environment described in this document pertains to all telecommunications terminals. In
addition to specifying RF immunity levels for equipment covered under the scope, this standard
provides information on test apparatus, testing system arrangement and measurement techniques.
As technology and application engineering techniques advance, the criteria contained in this
document will become subject to change.
27
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Draft 00
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
ANNEX B (INFORMATIVE)
686
Radio and TV Station Engineers
687
Telecommunications Companies
688
Communications Industry consultants
689
IEEE Standards Committee C63
690
American Radio Relay League
691
Consumers
692
Telecommunications Equipment Manufacturers
693
Industry Trade Associations
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
(To be published as TIA/EIA-631-A
During 1991 and 1992, a continuing high level of consumer complaints of Radio Frequency
Interference (RFI) trouble in telecommunications terminal equipment prompted the Federal
Communications Commission (FCC) to seek industry support for problem mitigation. Under the
auspices of the FCC's Los Angeles Regional Field Office, a series of open meetings was convened to
address opportunities for public education, product design improvement and related issues. During
these meetings, the FCC sought the participation of the Telecommunications Industry Association
(TIA), among other groups, and approval was obtained for the TR-41 User Premises Telephone
Equipment Requirements Committee to initiate various projects in support of the FCC program.
It was determined that the RFI mitigation effort could be best accommodated in the TR-41.7
Environmental and Safety Considerations Subcommittee; thus, working group TR-41.7.3 on
Electromagnetic Compatibility (EMC) Considerations was established. In the administration of its
work on the various projects, the working group received supporting comments from the following
sources:
1. The FCC
The initial task of the subcommittee was the preparation of a single page, double-sided procedural
document to assist the consumer in analyzing an apparent instance of RFI in a telecommunications
terminal. Simple, step-by-step test recommendations were included together with recommendations
on the use of RFI filters.
With the completion of the procedural document, the subcommittee laid plans for the origination of a
standard for RFI immunity levels and test methods. In as much as considerable information was
available within the public domain on the topic of RF immunity, the committee elected to avail itself
of various existing documents for its purposes. This approach permitted the project to be completed
within a much shorter time interval than would have otherwise been the case. Listed below is the
primary reference standard.
Technical Advisory Document (TAD) 8465, "Electromagnetic Compatibility Requirements and Test
Methods for Telecommunications Equipment and Systems", Issue 1, April 1992, Bell Canada .
At the time of the development of this standard, information regarding metallic (differential) RF
signals was limited. As this information becomes available, it is anticipated that it will be
incorporated in this standard to fully characterize the RF immunity of Telephone Terminal
Equipment (TTE).
28
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
(To be published as TIA/EIA-631-A)
Draft 00
SP-3210RV1
TR41.7.3-01-02-002
The Electronic Industry Association (EIA) standards documents are developed within the technical
committees of the EIA and the standards coordinating committees of the EIA standards board.
Members of the committees serve voluntarily and without compensation. The companies they
represent are not necessarily members of the EIA. The standards developed within the EIA represent
a consensus of the broad expertise on the subject. This expertise comes from within the EIA as well
as from those outside the EIA that have expressed interest. The viewpoint expressed at the time this
standard was approved was from the contributors' experience and the state of the art at that time.
Users are encouraged to check to see that they have the latest revision of the standard.
In 1988, the Telecommunications Sector of the EIA became the TIA under the TIA technical council.
While the TIA is a separate corporation, it conducts its standards activities through the EIA
organization. Standards developed by TIA are frequently submitted to American National Standards
Institute (ANSI) for approval. When approved as American National Standards, they are referred to
as ANSI/TIA/EIA standards.
ANSI/TIA/EIA reviews most standards every 5 years. At that time, standards are reaffirmed,
rescinded or revised according to the submitted proposed revisions. Proposed revisions to be
included in the next revision should be sent to the committee chair or to ANSI/TIA/EIA.
This standard has been prepared by the Working Group TR-41.7.3 under the jurisdiction of the
Subcommittee TR-41.7 and approved by the Technical Committee TR-41.
29
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Draft 00
(To be published as TIA/EIA-631-A
736
ANNEX C (INFORMATIVE)
737
738
739
740
741
742
743
744
745
CONSIDERATIONS
746
747
748
749
A 55 dBSPL noise level would be objectionable to most people, but this noise would only occur with
exceptional RF signals. If the noise is intermittent, such as might occur with citizens band (CB)
radio, the noise could be tolerable. If the noise is constant or involves intelligible speech,
additional RF filtering may be necessary.
750
751
Functionality with the exceptional RF signals is important because the product should be usable in
the event of an emergency.
752
753
The electromagnetic environment contains a broad range of frequencies, but only those frequencies
likely to cause interference in TTE are used.
754
755
756
757
758
The electromagnetic environment does not have a uniform field strength with frequency, being
strongest in the AM radio band. However, equipment is tested with a constant strength RF signal
to harmonize with international test methods. Instead of testing equipment with a variable signal
strength and a constant noise criterion, equipment is tested with a constant signal strength and a
variable noise criterion.
759
760
761
762
763
RF signals from 150 kHz to 30 MHz are picked up primarily on building wiring and conducted into
the equipment. The conducted immunity requirements are more severe than the radiated
requirements over the same frequency range, but the radiated tests are maintained because they
are not a burden to perform. RF signals from 30 to 150 MHz are picked up primarily by the
handset cord and wiring within the equipment, so there is no conducted equivalence.
764
765
766
767
768
It is known that conducted RF signals have a metallic component to the largely longitudinal signal. It
is caused by either the imbalance in twisted pair outside cable, or the differential pickup in quad
inside wire. The T-LISN specified is not perfectly balanced and is a rough simulation of the
cable situation. As T-LISNs with better balance are introduced, simulation of the cable
imbalance should be added to the test circuit.
769
770
771
772
773
INFORMATIVE REFERENCES
774
775
776
2. Hansen, D., Wilson, P., Königstein, D., Garbe, H., Emission and Susceptibility Testing in a
Tapered TEM Cell, 8th International Zürich Symposium on EMC 1989, pp. 227-232, Zürich,
Switzerland, March 1989.
777
778
3. Bell Canada Technical Advisory Document (TAD) 8465, Issue 1, Electromagnetic Compatibility
Requirements and Test Methods for Telecommunications Equipment and Systems, April 1992.
Equipment complying with this standard is expected to provide reasonable immunity to RF
interference at an acceptable cost to the consumer. However, a few percent of the population may
continue to experience RF interference when using compliant equipment. The requirements of clause
5 represent a balance of the factors involved in achieving RF immunity such as:
1. Two test methods were possible - using typical RF signals and a low noise criterion, or using
strong RF signals and a high noise criterion. Since measuring low noise levels is very difficult,
the latter method is used. The methods are not strictly equivalent because noise levels are not
linear with RF signal strength, but the method chosen is expected to be the more severe.
The following references, although not normative, contain information that provides background to
this Standard. At the time of publication, the editions indicated were valid.
1. Crawford, M. L. and Workman, J. L., Using a TEM cell for EMC measurements of electronic
equipment, National Bureau of Standards, NBS technical note 1013, April 1979.
30