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ANSI-ASC-C63®: Status of the Committee’s EMC Standards for 2012

The American National Standards Institute (ANSI)-Accredited Standards Committee (ASC) C63® (hereinafter C63) has been a United States Standards Development Organization for over 60 years. Its main focus is standards in the electromagnetic compatibility (EMC) engineering discipline. Recently, C63 has become more active in the telecommunications (transmitters and receivers) technical area to reflect the growing importance of wireless devices in today’s society. This article describes some of the most recent activity in the domain of C63 standards.

C63.4

ANSI C63.4 (American National Standard for Methods of Measurement of Radio-Noise Emissions from Low-Voltage Electrical and Electronic Equipment in the Range of 9 kHz to 40 GHz) is the most well-known of the C63 standards. It has been adopted by the United States Federal Communications Commission (FCC) as the official test methods guideline document for Part 15 of the FCC Rules.

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How to Perform a Radiated Emissions Measurement

Radiated emissions testing is the measurement of the electromagnetic field of the emissions that are unintentionally being generated by the equipment under test.

The 2009 edition of C63.4 is presently being revised. Areas of interest include:

  1. addition of what should be on
  2. visual displays based on the size of the screen
  3. information on test setups for
  4. tablet PCs
  5. clarification on the proper use of the average detector
  6. three tables of acceptable antennas; general measurements, NSA measurements, and compliance testing measurements
  7. test site validation intervals for sites above 1 GHz
  8. antenna factors for site validation
  9. non-manipulation of bundled cables
  10. additional clarifications on testing above 1 GHz
  11. addition of measurement uncertainty
  12. removal of the testing of  transmitters and receivers
  13. annex B improvement to show methods of verification of LISNs

The “tables of acceptable antennas” are being driven partly by the topic of hybrid antennas. The hybrid antenna consists of a combination of a biconical antenna with a log periodic dipole array antenna. They usually cover the frequency range from 30 MHz to 1000 MHz and they have been used in the EMC industry since around 1993 when they were first introduced in Europe. Many technical studies show that hybrid antennas are equivalent to the individual antennas that make up the “hybrid.”  Some studies show a difference under certain conditions especially a 3-meter horizontal antenna measurement distance. The draft version of C63.4 is addressing this issue.

One overall goal of the standard working groups in C63 is to move the language and criteria closer to the international standards. The draft version of C63.4 is presently striving to do that.

C63.5

The well-referenced C63.5 (American National Standard for Calibration of Antennas Used for Radiated Emissions Measurements in Electromagnetic Interference (EMI) Control) is being revised by the C63 Committee. The standard was last revised in 2006. The standard is being rewritten to reflect changes in technology over the last 6 years.

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Topics being addressed include: scope expansion, smooth connection to other C63 standards, redefining “reference site”, inclusion of additional reference dipole antennas, and define “antenna calibration site” and “near free-space geometry”.

One of the key issues is whether antennas can be calibrated in a semi-anechoic chamber (SAC) for antennas valid in the frequency range 30 MHz to 1000 MHz. The present C63.5 standard specifies that only an open area test site (OATS) can be used for calibrating antennas. The OATS must meet a tighter normalized site attenuation (NSA) criteria than a compliance testing OATS; i.e., plus or minus 2 dB versus 4 dB. The question is whether a SAC that meets the +/- 2dB criteria can be used for antenna calibration.

The advantages of testing antennas in a semi-anechoic chamber (SAC) are obvious:

  1. no weather conditions to adversely affect the testing
  2. controlled temperature and humidity conditions
  3. no ambient signals to interfere with the antenna calibration measurements

C63.10

ANSI C63.10-2009 (American National Standard for Testing Unlicensed Wireless Devices) is the standard that encompasses unlicensed receivers and transmitters. The second edition is being worked on to expand on the success of the first edition. The working group has been very active and has had a large number of participants. The wireless technology field is changing rapidly and the working group is reflecting some of those changes in the second edition.

Topics being addressed include: new FCC procedures for DTS devices, updated procedures for UNII devices, additional details on measurements above 1 GHz, and revisions to the annexes of the standard.

Subcommittee Activities

SC-1 Techniques and Development
SC-1 provides the technical expertise for incorporating new or existing measurement techniques and associated instrumentation related to EMC into C63 documents. This subcommittee is responsible for the three standards mentioned in the first part of this article. In addition, it is responsible for three new standards: C63.23 (Measurement Uncertainty), C63.25 (Test Site Validation – Time Domain), and C63.26 (Licensed Transmitter Test Methods).  The working group chairs for those three standards are, respectively, Bob DeLisi, Dennis Camell, and Art Wall. Additional standards under the care of SC-1 include: C63.2 (EM Noise and Field Strength Instrumentation) and C63.22 (Guide for Automated EMI Measurements). Subcommittee 1 is presently chaired by Dennis Camell, NIST-Boulder.

SC-2 E3 Terms and Definitions
This subcommittee is chaired by Marcus Shellman. The responsibility of SC-2 resides in its efforts to develop and document new and emerging definitions and terminology for use by the C63 Committee. The Subcommittee has recently refined its process for accepting definitions into C63.14 (Definitions). Working Group 1 of SC-2 also was assigned an action item to review military standards issued in the last five years for appropriate EMC definitions.

SC-3 International Standardization
This subcommittee actively discusses international standards and organizations for their potential impact on C63 standards.

Its Scope is as follows: Subcommittee 3 provides a forum for comparing international standards activities to C63 membership standards activities and makes recommendations to the
C63 Main Committee on possible US positions on international EMC matters, to facilitate harmonization of national and international standards, considering US regulatory as well as commercial requirements. Subcommittee 3 may make recommendations to the C63 Main Committee about introducing the work of C63 to the US National Committee Technical Advisory Groups for submission to international standards. Paul Andersen is the current chair of Subcommittee-3.

SC-5 Immunity Testing
This subcommittee has approximately 20 members and the SC is chaired by Steve Whitesell.

It has responsibility for C63.15 (Immunity Measurement and Instrumentation) and C63.16 (ESD Testing Methodology Guide).

A new standard under development in this Subcommittee is C63.20 (Nuclear Power Plant Immunity). Additional participants interested in this new standard should contact Chair Steve Whitesell (s.whitesell@ieee.org) for additional information.

A fourth standard under development in this subcommittee is C63.24 (Generic In-Situ Immunity Evaluation). The chair of the working group looking at this standard, Steve Berger, has indicated that an additional teleconference must be held with the working group before the first draft document will be ready for subcommittee ballot.

SC-6 Laboratory Accreditation/Conformity Assessment
This subcommittee is working on C63.11 (Inter-lab Comparison EMC Testing) and C63.8 (Guidance on Specifying Requirements for the Calibration and Verification of EMC Test Equipment). The subcommittee has about 20 members and is chaired by Victor Kuczynski.
Representatives from four laboratory accreditation bodies sit on the subcommittee; U.S. Department of Commerce-NIST/NVLAP, A2LA, A-CLASS, and Laboratory Accreditation Bureau (LAB).

SC-7 Unlicensed Personal Communications Services Devices
The subcommittee is in the process of revising C63.17 (Unlicensed Personal Communications Service [UPCS] Devices). It is being revised in response to recent United States Federal Communications Commission (FCC) changes in the UPCS band service rules.

A new standard is being developed by SC-7; its number is C63.27 and its title is “American National Standard on Evaluation of Wireless Coexistence”. It is being developed in response to a recommendation in a general report on the topic. The standard will develop evaluation methods and test procedures for assessing the ability of a wireless device to coexist in its electromagnetic operating environment.

A committee study project is also being started to investigate radio receiver design for improved coexistence. Both the study project and C63.27 are considered to be in the area of “spectrum management”. The industry desperately needs test methods that have a high correlation to field experiences with real radio situations. Individuals interested in this project can contact the chair of the subcommittee, Stephen Berger, Stephen.berger@ieee.org.

SC-8 Medical Equipment EMC Testing
This subcommittee is responsible for developing and maintaining C63 standards for medical devices. The subcommittee is chaired by Bob DeLisi of UL and it is responsible for C63.18 (On-Site Medical Immunity Testing) and C63.19 (EMC and Hearing Aids).

The latest revision to C63.18 is undergoing the IEEE editing process and, as a result of that, there were some changes made to the use of trademarked terms. In general, trademarked names must be identified in the footnotes and generic names can be used in the text.

C63.19-2011 was recently adopted in an FCC Report and Order (WT Docket No. 07-250) with a 12-month transition period. Additional interpretations have been requested by users of the standard. These interpretations are being addressed by C63 and will be explained in detail in a workshop planned for the fourth quarter of 2012.

A study project was initiated in this SC to look at developments at the international standards level with hearing aid immunity test methods and techniques. The study project will document their findings in a report to the main committee of C63.

Joining a C63 Working Group

The C63 Committee is always looking for additional volunteer to help document and develop standards in the EMC arena. There is no financial charge to join a working group but the individual is expected to attend meetings and participate in the work effort.

If an individual wants to join a subcommittee, there is $550 annual fee and the individual is expected to participate in the meetings and development activities of the subcommittee. favicon

 

author_hoolian-dan Daniel D. Hoolihan
is the Founder and Principal of Hoolihan EMC Consulting. He is a Past-President of the EMC Society of the IEEE and is presently serving on the Board of Directors. He is presently an assessor for the NIST NVLAP EMC and Telecom Lab Accreditation program. Also, he is the Vice-Chair of the ANSI ASC C63® committee on EMC.

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