New ANSI C63.4-2003
Workshop
Boston, Massachusetts, August 15-16, 2003
This article diverges from the usual
description of EMCS standards activity. We have done this
to bring to the attention of Newsletter readers a major
workshop on a critical EMC measurement standard. This
is one of the most used standards in the US and other
parts of the world by those manufacturers that import
into the US. In particular, this standard has been recently
revised and hence sorting through the implications and
changes is considered worthwhile to highlight in the Newsletter.
So here we go.
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Held in conjunction with the IEEE EMC Symposia,
the continuing series of workshops addresses ANSI C63.4, which
is the standard the FCC references to perform radiated and conducted
emission measurements for Information Technology Equipment. This
year, it will cover the new 2003 update of the standard which
will be released by summer this year and hopefully before the
15-16 August workshop planned for Boston. The IEEE EMC Society
is a voting member of the ANSI Accredited Standards Committee
C63 (EMC) and in fact the chairman of our EMCS Standards Development
Committee-Stephen Berger-is our voting representative. So there
is a close relationship between our EMC Society standards activity
and the work of ANSI as well as work of other standards committees
internationally via our EMCS Standard Advisory and Coordination
Committee (SACCom). SACCom is chaired by Elya Joffe, who, incidentally,
was the chairman of the 2003 IEEE International Symposium on EMC
in Istanbul this year.
In order of their appearance in the ANSI C63.4-2003 document,
here are highlights of the changes from the 1991 version of the
standard. Further details will be covered during the workshop
in Boston.
-
Clarify what is mandatory (shall statements)
and what is suggested (should statements) and that the text
takes precedence over any figures which are examples (Clause
1.2).
-
State that for the time being, no telecommunication
port conducted emission measurements nor measurements using
ferrite tube loading on I/O cables exiting the test site for
table top tests are required (Clause 1.2).
-
Use of the Federal Communications Commission
definition of personal computer for further clarity (Clause
3.1).
-
Include reference to ISO/IEC 17025 on competency
of testing.
-
Allowance of using emission measurement
receiving equipment such as spectrum analyzers which do not
meet all the reference receiver requirements in either ANSI
C63.2 or CISPR 16-1. In case of disputes, a receiver meeting
either reference receiver specification takes precedence (Clause
4.1.1).
-
More detailed information on the use of
spectrum analyzers and what additional features have to be employed
such as input filters, overload protection, etc. Detailed information
also includes clarification of bandwidth requirements. (Clauses
4.1.1.2, 4.2, and 5.1.2).
-
The use of either the 1988 or 1998 editions
of C63.5 on antenna calibration remains, awaiting the publication
of C63.5-2003 (Clause 4.1.5.3).
-
Clarification of the calibration interval
requirements for measurement equipment (Clause 4.4.1).
-
Noting that cable insertion loss should
include environment considerations such as temperature and damage
effects (Clause 4.4.5).
- Clarification of the use of the vertical coupling plane for
performing conducted emission measurements (Clause 5.2.2).
- Correction to Table 2, third column where the source height
is 2 meters, not 3 meters when performing normalized site measurements.
- Clarification of placement of a table top peripheral when there
is only 1 peripheral and mouse and keyboard cables for PC testing
(Clauses 6.2.1.2 and 6.2.2.2).
- New setups for testing when power accessories such as AC/DC
power packs are used to take into account when they are the equipment
under test and when they are not (Clause 6.2.1.2).
- Allowance of using "loop back" cable arrangements
for large equipment where such cables link with remote equipment.
This allows cables to extend away from an output port of the EUT
and then return to an input port of the EUT in a manner to provide
both a horizontal and vertical exposure (Clause 6.2.2.3).
- Clarification that all power cords associated with the system
that is being tested on the test site shall be checked for conducted
emissions during exploratory measurements. The result will then
help to establish the arrangement for final testing.
- Warning that not searching full antenna height elevation between
1 and 4 meters in exploratory testing in a semi-anechoic chamber
(if used) may not yield sufficient radiated emission information
for the final compliance test at a site which meets Normalized
Site Attenuation requirements (Clause 8.3.1.1).
- Clarification of what set of power cords and associated phase
wiring conducted emission data is the set of data to select the
6 highest emissions with respect to the limit (Clause 10.1.8.1).
- For ITE testing in Clause 11:
a. Clarification of EUT setups when the host of an ITE system
being tested is the EUT and when it is not (Clause 11.1.1 - new
clauses 11.1.1.1 and 11.1.1.2).
b. Clarification of the minimum ports that need to be populated
with cables and accessories, i.e. when to add other port connections
in addition to serial and parallel ports, i.e. ports that support
other I/O protocols such as USB, etc. (Clauses 11.1.2 and 11.2).
c. Clarification of peripheral/accessory EUT setups when they
are the EUT and when they are not (Clause 11.1.2.1).
- Clarification of the bandwidth requirements for incidental
radiators not ITE in Clause 12.2.5.
- Clarification of test frequencies for intentional radiators
in Clause 13.1.1.
- Correction in the formula shown in the worksheet in Appendix
A (Table A.1 Site Attenuation Worksheet).
- Annex C (Site Attenuation Deviations) is removed as it is covered
in ANSI C63.7.
- Annex D (Old Annex E which is relabeled Annex D due to the
removal of Annex C), Annex G (Old Annex H) and Annex H (Old Annex
I): removing the 6 dB bandwidth references as what is actually
used is contained in Clause 4.2 which refers to ANSI C63.2 and
CISPR 16, Part 1.
- Annex E (Old Annex F) on LISN calibration:
a. Caution of the effects of power source and any filters to suppress
external power supply noise when calibrating LISN impedance.
b. Further requirements and instructions when using scalar and
vector network analyzers or known artifacts during the LISN impedance
calibration.
- Annex G (Old Annex H) on unintentional radiators other than
ITE:
a. Additional instructions on how to set the sweep time and video
bandwidth.
b. Introduction of impulse bandwidth in determining the 1 MHz
bandwidth for this measurement.
c. Precautions when to use double shielded coaxial cables.
- Annex H (Old Annex I) on intentional radiators:
a. Further details on use of test instrumentation including setting
of the frequency span, video bandwidth and resolution bandwidth.
b. Introduction of impulse bandwidth in determining the 1 MHz
bandwidth for this measurement.
- Annex I (Old Annex J) on applicable clauses for type of EUT
measurements
a. Correction to the reference clauses.
b. Addition of Annex M on TEM waveguide device use where appropriate.
c. Inclusion of clauses that are applicable.
- Annex M (may be changed to Annex L when annex lettering is
updated):
a. Explains EUT testing complexities using TEM devices where the
internal turntable is not horizontal with the floor of the test
area.
- Changes to Figures:
a. Figure 7: Correct reference to show Tables 1, 3, and 4, not
Tables 1, 2, and 4.
b. Figure 8c: Correct note showing transmit antenna height and
delete rear antenna position.
c. Figure 8d: Correct note showing transmit antenna height and
that it is only 1 antenna height for this part of the NSA test.
d. Figure 10a: Remove extraneous "+" signs.
e. Figure 12b: Correctly show distance arrows between the closest
point of the EUT and the LISN.
f. Figure 13: Various clarifications including positioning of
parts of the EUT which should be flush with the table top edges
and that the nominal 1 by 1.5 meter table top may be extended
in both dimensions.
g. Equations in present Annex M (use of TEM waveguides):
i. Correct the expression for the mean and standard deviation.
ii. Correct the equations shown on the sample spreadsheet (Table
M1.1).
The C63.4 Workshop registration form is published
in the advance program for the Boston Symposium as well as advertised
in trade magazines. For information on registration and the costs,
please contact the registrar:
Janet O'Neil
ETS-Lindgren
22117 NE 10th Place
Sammamish, WA 98074
j.n.oneil@ieee.org
For further information on the technical content
of the workshop, contact the author on d.heirman@ieee.org.
Please note that due to the costs for the workshop, the workshop
can only be held if there are at least 15 registered by 11 July
2003. So do not wait to register if you would like to attend.
Please make any travel arrangements to accommodate the possible
cancellation of the workshop. EMC
Comments received after the C63.4 Workshop
in Minneapolis, Minnesota 2002:
"The
C63.4 workshop gave me a better understanding of how to
interpret the document and its intent." - Richard Georgerian,
Carrier Access
"The
workshop was very informative in providing new updates on
measurements above 1 GHz and the use of GTEMs. I appreciated
the review of the terminology informative/normative and
shall/should." - Rolando Velbis, Hitachi Home Electronics
America
"Great review!"
- Michael Stone, L.S. Compliance
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