EMC Standards Activities

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.


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.

  1. 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).
  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).
  3. Use of the Federal Communications Commission definition of personal computer for further clarity (Clause 3.1).
  4. Include reference to ISO/IEC 17025 on competency of testing.
  5. 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).
  6. 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, 4.2, and 5.1.2).
  7. The use of either the 1988 or 1998 editions of C63.5 on antenna calibration remains, awaiting the publication of C63.5-2003 (Clause
  8. Clarification of the calibration interval requirements for measurement equipment (Clause 4.4.1).
  9. Noting that cable insertion loss should include environment considerations such as temperature and damage effects (Clause 4.4.5).
  10. Clarification of the use of the vertical coupling plane for performing conducted emission measurements (Clause 5.2.2).
  11. Correction to Table 2, third column where the source height is 2 meters, not 3 meters when performing normalized site measurements.
  12. Clarification of placement of a table top peripheral when there is only 1 peripheral and mouse and keyboard cables for PC testing (Clauses and
  13. 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
  14. 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
  15. 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.
  16. 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
  17. 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
  18. 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 and
    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
  19. Clarification of the bandwidth requirements for incidental radiators not ITE in Clause 12.2.5.
  20. Clarification of test frequencies for intentional radiators in Clause 13.1.1.
  21. Correction in the formula shown in the worksheet in Appendix A (Table A.1 Site Attenuation Worksheet).
  22. Annex C (Site Attenuation Deviations) is removed as it is covered in ANSI C63.7.
  23. 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.
  24. 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.
  25. 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.
  26. 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.
  27. 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.
  28. 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.
  29. 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
22117 NE 10th Place
Sammamish, WA 98074

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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