ANSI C63.4 is an 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. This standard specifies standardized methods, instrumentation, facilities, and test sites for measuring radio-frequency (RF) signals and noise emitted from electrical and electronic devices in the 9 kHz to 40 GHz frequency range. These standardized measurement methods/procedures are used for compliance testing to U.S. (47CFR15) and Canada (ICES-003) regulatory requirements. Note that the ANSI C63.4 standard does not include generic or product-specific emission limits. The RF noise emission limit requirements for electrical and electronic devices shall be obtained from other relevant voluntary and regulatory sources or emission standards. 

ANSI C63.4 standard applies to the RF emission measurement of a variety of electrical and electronic devices, as described in the document.  Where possible, the specifications details provided in this standard are harmonized with other national and international standards used for similar purposes. This standard is usually revised; the most current active edition of this standard is the ANSI C63.4 2014 edition, published by the Institute of Electrical and Electronics Engineers [IEEE]. The American National Standards Institute (ANSI) accredited the standard document. 

Usually, electrical and electronic devices emit unwanted electromagnetic energy or RF noise (RF emission) during operation. The emitted RF noise from a device may interrupt or damage other nearby devices in the operating environment in two ways. One is radiated emission, and the other one is conducted emission. In the case of radiated emission, the RF noise emanates from a device, travels via air, and will interrupt/damage the other device(s). In case of conducted emission, the RF noise emitted from a device travels via the connecting wires and power cards and will interrupt/damage the other device(s).  EMC Compliance testing is crucial to ensure that electronic devices do not emit excessive RF emissions that could interfere with other electronic equipment or violate regulatory limits of EMC emission standards. EMC testing involves emission measurement testing and immunity testing on electrical and electronic products. 

As already discussed, ANSI C63.4 specifies standardized test methods, instrumentation, facilities, and test sites for radiated and conducted EMC emission measurement tests for electrical and electronic devices in the 9 kHz to 40 GHz frequency range. This standard is used to characterize device emissions concerning voluntary or regulatory compliance requirements designed to protect authorized communication services. This standard helps manufacturers and testing laboratories ensure that the electrical and electronics products meet the regulatory requirements for electromagnetic compatibility (EMC). EMC refers to the ability of electronic and electrical devices to operate properly in their intended electromagnetic environment without causing interference to other devices.

Scope/Objective:

The scope/objective of the ANSI C63.4 standard is to specify radio-noise emission measurement methods/procedures, measuring instruments, measurement requirements, facilities, and test sites for both radiated and line-conducted emission measurement tests for low-voltage electrical and electronic equipment. The frequency range covered by this standard is 9 kHz to 40 GHz. A wide range/variety of electrical and electronic devices, as described in this standard, can generate radiated and line-conducted emissions (e.g., see section 1.2 of the ANSI C63.4 2014 edition). 

EMC testing laboratories use this standard to perform radiated and line-conducted emission measurement tests on products concerning voluntary or regulatory compliance requirements (i.e., EMC emission standard requirements) designed to protect authorized communication services. EMC emission standards are the standards that specify RF noise emission limits for electrical and electronic products. A product that comes to (or sells in) the market should have an RF emission level within the emission limit specified in the relevant EMC emission standard.

In the ANSI C63.4 standard, measurement instrumentation, facilities, and test sites are specified and characterized, including open-area test sites (OATS) and RF absorber-lined, metal test chambers used for radiated emission measurement. The emission measurement can be conducted in a shielded room or an emission test site. ANSI C63.4 says that all the instruments used in the conducted and radiated emission measurement tests shall be calibrated under the manufacturer's recommendations. Testing is permitted at the user end or manufacturer’s premises, if the equipment cannot be set up on an OATS or alternative test site such as RF absorber-lined metal test chambers. 

ANSI C63.4 document specifies general requirements for EUT (equipment under test) arrangements and operating conditions. It also specifies specific requirements for emission test data recording, test report content, and test report presentation, which should be used in conjunction with this standard. In addition to these, this standard covers emission measurement of information technology equipment (ITE), unintentional radiators other than ITE, and intentional radiators. The document contains a series of annexes that provide details for certain measurement methods and facilities. 

In this standard, the use of the word "shall" implies that the associated requirement must be met to satisfy this standard. The word "should" is used to indicate that the associated requirement is recommended but not mandatory. Here, tolerances on dimensions and distances are based on good engineering practice where not specified. The word "may" is used to indicate that the recommendation is at the discretion of the user. 

Alternative procedural documents may be employed in place of this standard, provided that they can demonstrate equivalent results. This standard doesn't cover all devices uniformly. It offers general methods for all devices within its scope and includes specific requirements for certain device types.

ANSI C63.4 standard Purpose and application (Use and applicability):

The ANSI C63.4 document, published by IEEE, is intended to standardize methods/procedures, instrumentation, and facilities used to characterize device emissions concerning voluntary or regulatory compliance requirements designed to protect authorized communication services. 

The ANSI C63.4 standard may be applied to emission measurement of a wide range of electrical and electronic devices, irrespective of their size or characteristics. The devices specified in this standard can be single, stand-alone units, or multiple, interconnected units. Even though the ANSI C63.4 standard has other possible uses, this standard is intended to be used for conducting emission measurements of unintentional radiators (including digital devices and receivers) as well as for conducting emission measurements of the digital device portions contained in or used in intentional radiators.

The emission measurement methods or procedures specified in this standard are intended to be applied primarily in controlled laboratory environments, but they may also be utilized for emission measurement of in situ devices (i.e., devices in their actual usage environments) where indicated.

The emission measurement methods described in this standard may not be adequate or applicable for measuring RF emission from incidental radiators, avionics, or industrial, scientific, and medical (ISM) equipment.

In conjunction with the application of the ANSI C63.4 standard (here, 2014 edition), a complete voluntary or regulatory requirement should specify the following information: 

a) specify limits and frequency ranges for both AC power-line conducted and radiated emission measurements

b) specify measurement antenna distances for radiated emission measurements

c) any uncommon requirements identification, such as the following:

• 1) Radiated magnetic field strength measurements below 30 MHz
• 2) Radiated electric field strength measurements below 30 MHz
• 3) Use of the absorbing clamp for radiated emission measurements
• 4) Relaxation of the limits for clicks (transients)
• 5) Use of the artificial hand for measurement of portable, hand-held devices
• 6) Any requirements that differ from the requirements contained/specified
• 7) Any requirement concerning statements of the uncertainty of the measurement results

Basic definitions described in this standard are given below:

ANSI C63.4 document describes the following basic definitions for Information technology equipment (ITE), intentional radiator, and unintentional radiator:

Information technology equipment (ITE): 

 a) Any equipment that has a primary function of either (or a combination of) entry, storage, display, retrieval, transmission, processing, switching, or control, of data or telecommunication messages and that may be equipped with one or more terminal ports typically operated for information transfer; 

 b) Any equipment with a rated supply voltage not exceeding 600 V. It includes, for example, data processing equipment, office machines, electronic business equipment, predominantly digital audio and video equipment, and telecommunications equipment that contains digital circuits. 

Intentional radiator: A device that intentionally generates and emits RF energy by radiation or induction. (FCC 47 CFR Part 15). 

Unintentional radiator: A device that generates RF energy for use within the device, or that sends RF signals by conduction to associated equipment via connecting wiring, but which is not intended to emit RF energy by radiation or induction. (FCC 47 CFR Part 15).

Conclusion:

ANSI C63.4 - is an 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. This standard specifies standardized methods, instrumentation, facilities, and test sites for measuring radio-frequency (RF) signals and noise emitted from electrical and electronic devices in the 9 kHz to 40 GHz frequency range. This standard also covers emission measurement of information technology equipment (ITE), unintentional radiators other than ITE, and intentional radiators. The RF noise emission limit requirements for electrical and electronic devices shall be obtained from other relevant voluntary and regulatory sources or emission standards. 

The ANSI C63.4 document, published by IEEE, is intended to standardize methods/procedures, instrumentation, and facilities used to characterize device emissions for voluntary or regulatory compliance requirements designed to protect authorized communication services. It helps device manufacturers and testing laboratories ensure that the electrical and electronics products meet the regulatory requirements for electromagnetic compatibility (EMC).