IEEE - 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
|Publication Date:||1 January 2009|
This standard specifies U.S. consensus standard methods, instrumentation, and facilities for measurement of radio-frequency (RF) signals and noise emitted from electrical and electronic devices in the frequency range 9 kHz to 40 GHz. It does not include generic nor product-specific emission limits. Where possible, the specifications herein are harmonized with other national and international standards used for similar purposes.
Uses of the word shall in this standard indicate a mandatory requirement that must be met to satisfy this standard. The word should is used to indicate that a requirement is recommended but not mandatory. Tolerances on dimensions and distances are based on good engineering practice where not specified. The word may is used to indicate a recommendation that is at the discretion of the user. In addition, notes in this document are informative and are not part of the requirements. In this standard, the text takes precedence over the figures because the text is complete and the figures are illustrative of a typical application of the text. Notes are used in the text for emphasis or to offer informative suggestions about the technical content of the standard, and these notes provide additional information to assist the reader with a particular passage but do not include mandatory requirements. Footnotes in text are included only for information, clarification, and/or aid applicable to the use of the standard, but mandatory requirements are not included in text footnotes.
Measurement methods are included for radiated and line-conducted emissions that can be generated by a variety of devices, as described in 1.2. Definitions are provided for terms and phrases contained in the text, in which the words do not represent obvious or common usage. Measurement instrumentation, facilities, and test sites are specified and characterized, including open-area test sites (OATS) and RF absorber-lined, metal chambers used for radiated emission measurement. Transverse electromagnetic (TEM) wave devices used for radiated emission measurement are treated in normative Annex F. The requirements of Annex F, when such tests are performed, shall take precedence in this standard. In most cases, measurement instrumentation and calibration requirements are only generally characterized in deference to standards dedicated to these subjects, which should be used in conjunction with this standard. The requirements for operation of test samples during measurements are presented for devices in general, as well as for specific types of devices that are frequently measured. Specific requirements for emission test data recording and reporting are presented with reference to general requirements contained in documents dedicated to standard laboratory practices, which should be used in conjunction with this standard. The main text is augmented by a series of annexes that provide details for certain measurement methods and facilities. Annex A provides an index of main text clauses to be used when testing particular equipment under test (EUT) types.
Purpose and applications
This document is intended to standardize methods, instrumentation, and facilities used to characterize device emissions with respect to voluntary or regulatory compliance requirements designed to protect authorized communication services. The specified procedures are intended to be applied primarily in controlled laboratory environments, but they may be used for emission measurement of in situ devices where indicated.
This standard may be applied to emission measurement of a variety of electrical and electronic devices, regardless of size and characteristics. The devices may be single, stand-alone units, or multiple, interconnected units.
These methods may be applied to the measurement of certain devices that purposefully radiate energy, such as intentional emitters, but they might not be applicable to licensed transmitters in the United States and other countries. Similarly, these methods may not be adequate for measurement of emissions from avionics or industrial, scientific, and medical (ISM) equipment.1
All limit specifications, relevant to a given emitting device, should be applied in their entirety to the characterization of the device over the specified frequency range in all propagation modes. Piecewise application is discouraged and runs the risk of incomplete characterization, which could fail to protect the authorized radio communications services in the manner intended. Emission limit requirements shall be obtained from other voluntary and regulatory sources, and certain other procedural documents shall be applied concurrently where specified herein. Still other procedural documents may be used as alternatives to this standard where equivalent results can be demonstrated. For regulatory applications invoking the methods in this standard, results obtained as prescribed herein shall take precedence over results obtained with alternative methods.
Not all clauses in this standard are applicable to all devices that can be measured with these methods. The nature of this standard is to specify general methods that may be applied to all devices within its scope and to supplement these methods with particular requirements for some types of devices. Device-particular requirements take precedence over general requirements. See Annex A for guidance in applying this standard to specific types of devices.
A complete voluntary or regulatory requirement should specify the following information in conjunction with the application of this standard:
a) Limits and frequency ranges for both ac power-line conducted and radiated emission measurements
b) Measurement antenna distances for radiated emission measurements
c) Identification of any uncommon requirements such as the following:
1) Radiated magnetic field strength measurements below 30 MHz (see 8.2.1)
2) Radiated electric field strength measurements below 30 MHz (see 8.2.2)
3) Use of the absorbing clamp for radiated emission measurements (see Clause 9)
4) Relaxation of the limits for clicks (transients) (see Clause 14)
5) Use of the artificial hand for measurement of portable, hand-held devices (see 6.2.12)
6) Any requirements that differ from the requirements contained herein
7) Any requirement concerning statements of uncertainty of the measurement results (see ISO/IEC 17025:20052).
1Various standards used in the United States require emission measurements below 9 kHz (e.g., MIL-STD-461F [B19], MDS-201-0004 [B18], and SAE ARP 1972:1986 [B21]). These have their own measurement procedures and thus require no reference to ANSI C63.4 emission measurement procedures. However, they may require reference to ANSI C63.2 and ANSI C63.4 for instrumentation specifications. Individual procurement requirements shall take precedence.
2Information on references can be found in Clause 2.