In United States regulatory law, an unintentional radiator is any device that is designed to use
radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the ...
electrical signals within itself, or sends radio frequency signals over conducting cabling to other equipment, but is not intended to radiate radio frequency energy. An incidental radiator is a device that can generate radio frequency electrical energy even though it is not intentionally designed to do so.
United States Code 47, §15.3(n) - Definitions
/ref> Unintentional and incidental radio frequency radiation can interfere with other electronic devices. In the United States, limits on radiated emissions from unintentional and incidental radiators are established by the Federal Communications Commission. Similar regulations have been promulgated by other governments. Reference is usually made in regulations to technical standards established by organizations such as ANSI, IEC and ITU.
Example unintentional and incidental radiating devices
A computer is a typical example of an unintentional radiator. Radio frequency signals used within the computer circuitry may be unintentionally coupled to the power cord or to an interconnecting cable, which then acts as an antenna.
A radio receiver will often use an intermediate frequency which is detectable outside the radio—the concept behind at least one audience measurement
Audience measurement measures how many people are in an audience, usually in relation to radio listenership and television viewership, but also in relation to newspaper and magazine readership and, increasingly, web traffic on websites. Sometim ...
concept for roadside detection of radio station
Radio broadcasting is transmission of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radi ...
s which passing motorist
Driving is the controlled operation and movement of a vehicle, including cars, motorcycles, trucks, buses, and bicycles. Permission to drive on public highways is granted based on a set of conditions being met and drivers are required to fol ...
s are listening to.
Examples of incidental radiators include electric motors
An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate forc ...
, transformers
''Transformers'' is a media franchise produced by American toy company Hasbro and Japanese toy company Tomy, Takara Tomy. It primarily follows the Autobots and the Decepticons, two alien robot factions at war that can transform into other forms ...
, dimmers, and corona
Corona (from the Latin for 'crown') most commonly refers to:
* Stellar corona, the outer atmosphere of the Sun or another star
* Corona (beer), a Mexican beer
* Corona, informal term for the coronavirus SARS-CoV-2, which causes the COVID-19 di ...
from electrical powerlines. Radiated emissions from these commonly create interference
Interference is the act of interfering, invading, or poaching. Interference may also refer to:
Communications
* Interference (communication), anything which alters, modifies, or disrupts a message
* Adjacent-channel interference, caused by extr ...
on AM radio receivers and on television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
receivers.
Regulatory overview
In North America, active devices that are characterized as unintentional radiators are governed by Part 15
Code of Federal Regulations, 'Title 47, Part 15(47 CFR 15) is an oft-quoted part of Federal Communications Commission (FCC) rules and regulations regarding unlicensed transmissions. It is a part of Title 47 of the Code of Federal Regulations ( ...
of the FCC
The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdictio ...
regulations. In Canada, Innovation, Science and Economic Development considers them as interference-causin
Equipment
Globally, most domestic regulation of unintentional radiators are based on ITU
The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
recommendations.
Generally, this means the device leaks a signal at some level. Microprocessor-controlled appliances, anything with a clock signal, and switching voltage regulators all make some kind of noise, at the repetition frequency and at harmonics. In most countries, government agencies regulate how much leakage is tolerated. This prevents leakage from cable television
Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with bro ...
systems, for example, from interfering with radio communications between aircraft and control tower
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airs ...
s.
Because it costs money to filter out noise, there is always a balance struck between regulatory compliance and perfect filtering in these devices. Microwave oven
A microwave oven (commonly referred to as a microwave) is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce ...
s or devices with microprocessors may leak within allowable limits but may generate an undesired signal that interferes with a licensed communications device. It also generally means that users who intentionally radiate signals (TV stations
A television channel is a terrestrial frequency or virtual number over which a television station or television network is distributed. For example, in North America, "channel 2" refers to the terrestrial or cable band of 54 to 60 MHz, with ...
and cell phone companies) can order the device turned off if it interferes with their licensed operations.
There is an entire industry based on regulatory compliance: manufacturers shipping a product to a foreign country must comply with each country's limitations on leakage of interfering signals. For example, in Germany the TÜV issues regulatory rules for unintentional radiators. The big cylindrical bumps on the cable to monitors and laptop chargers are ferrite cores Ferrite may refer to:
* Ferrite (iron), one of the allotropes of iron that is stable at room temperature and pressure, α-Fe
* Ferrite (magnet), a ferrimagnetic ceramic material
Ferrite family, a Spanish family that has members all over the world.
...
which reduce undesired signals.
See also
* Intentional radiator
* Product certification
Product certification or product qualification is the process of certifying that a certain product has passed performance tests and quality assurance tests, and meets qualification criteria stipulated in contracts, regulations, or specifications ...
References
{{reflisthttps://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/h_sf06127.html
Radio electronics
Electromagnetic compatibility