n. (Abbr. RF)
- The frequency of the waves transmitted by a specific radio station.
- A frequency in the range within which radio waves may be transmitted, from about 3 kilohertz to about 300,000 megahertz.
| Dictionary: radio frequency |
| 5min Related Video: radio frequency |
| Columbia Encyclopedia: radio frequency |
| Medical Dictionary: ra·di·o frequency |
| WordNet: radio frequency |
The noun has one meaning:
Meaning #1:
an electromagnetic wave frequency between audio and infrared
| Wikipedia: Radio frequency |
|
|
This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (May 2009) |
Radio frequency (RF) radiation is a subset of electromagnetic radiation with a wavelength of 100km to 1mm, which is a frequency of 300 Hz to 3000 GHz,[1] respectively. This range of electromagnetic radiation constitutes the radio spectrum and corresponds to the frequency of alternating current electrical signals used to produce and detect radio waves. RF can refer to electromagnetic oscillations in either electrical circuits or radiation through air and space. Like other subsets of electromagnetic radiation, RF travels at the speed of light.
Contents |
In order to receive radio signals, for instance from AM/FM radio stations, a radio antenna must be used. However, since the antenna will pick up thousands of radio signals at a time, a radio tuner is necessary to tune in to a particular frequency (or frequency range).[2] This is typically done via a resonator (in its simplest form, a circuit with a capacitor and an inductor). The resonator is configured to resonate at a particular frequency (or frequency band), thus amplifying sine waves at that radio frequency, while ignoring other sine waves. Usually, either the inductor or the capacitor of the resonator is adjustable, allowing the user to change the frequency at which it resonates.[3]
Electrical currents that oscillate at RF have special properties not shared by direct current signals. One such property is the ease with which they can ionize air to create a conductive path through air. This property is exploited by 'high frequency' units used in electric arc welding, although strictly speaking these machines do not typically employ frequencies within the HF band. Another special property is an electromagnetic force that drives the RF current to the surface of conductors, known as the skin effect. Another property is the ability to appear to flow through paths that contain insulating material, like the dielectric insulator of a capacitor. The degree of effect of these properties depends on the frequency of the signals.
Radio frequency (RF) energy has been used in medical treatments for over 75 years[4] generally for minimally invasive surgeries and coagulation, including the treatment of sleep apnea.[5]
|
|||||
|
|||||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
| Shopping: radio frequency |
| antenna power (electromagnetism) | |
| electromagnetic environment (communications) | |
| Q band (electromagnetism) |
| What is the FM radio frequency for 702? Read answer... | |
| What is the radio frequency range of FM? Read answer... | |
| What is the frequency of fm radio waves? Read answer... |
| What is the range of radio frequency? | |
| How do you control radio frequency interference? | |
| What is the EAS radio system frequency? |
Copyrights:
![]() | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more | |
![]() | Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/. Read more | |
![]() | Medical Dictionary. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Read more | |
![]() | WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. Read more | |
![]() | Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Radio frequency". Read more |
Mentioned in