radio frequency

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frequency

 [fre´kwen-se]
1. the number of occurrences of a periodic or recurrent process in a unit of time, such as the number of electrical cycles per second measured in hertz. In cardiac pacing terminology, frequency is expressed by the formula: frequency = ½ × pulse width.
2. the number of occurrences of a particular event or the number of members of a population or statistical sample falling in a particular class.
radio frequency the range of frequencies of electromagnetic radiation between 10 kilohertz and 100 gigahertz, used for radio communication.
relative frequency the ratio of the number of occurrences of a specified phenomenon in a population to the total size of the population.
urinary frequency urination at short intervals without increase in daily volume of urinary output, due to reduced bladder capacity or cystitis.

radio frequency

An MRI term for an electromagnetic wave with a frequency in the same range as that used for transmitting radio and television signals. The RF pulses used in MRI are usually in the 1–100 megahertz range, which cause heating of a structure or tissue due to RF pulse absorption.
References in periodicals archive ?
We measured the critical magnetic field strengths of superconducting Nb3Sn samples in both static and radio-frequency fields, says Sebastian Keckert, first author of the study, who is doing his doctorate as part of the Knobloch team.
Here [t.sub.1] is the neutron flight time through the coil, and the unit vector [n.sub.2] is determined by a phase [delta] of a radio-frequency field at the moment a neutron enters a coil.
Lesh says the radio-frequency technique appears safe and effective.
The emissions lasted for only a couple of minutes, but the astronomers kept the instrument on that frequency for a week while they set up a second receiver to monitor possibly misleading radio-frequency interference.
For skilled designers, researchers, and engineers as well as students, electrical engineers review recent developments in optimizing the performance of analog, mixed-signal, and radio-frequency circuits.
NIST researchers led efforts within the IEEE 802.15 Task Group on Coexistence to study, characterize, and quantify the radio-frequency interference between Bluetooth and the now widely deployed IEEE 802.11b WLAN devices.
telescope that had served for 26 years as a leading tool worldwide for studying cosmic sources of radio-frequency signals came crashing down in minutes last week.
The main topics of the conference were topical issues of regulation of the radio-frequency spectrum and the development of new technologies, in particular, the introduction in the Russian Federation of the standard for the fifth generation of mobile communication (5G).
Radio-Frequency Heating in Food Processing: Principles and Applications
Following the long established theory of synchrotron radiation emission, all synchrotron radiation is emitted in harmonics of the frequency of the accelerating radio-frequency field.
NASA has been studying debris hazards to (and caused by) spacecraft for a decade, and there is a host of international organizations involved with the dense thicket of regulations governing radio-frequency interference.
As a result of the works, communication and broadcasting services were provided in full, the final competitive days of the World Football Championship were held in conditions of proper use of the radio-frequency spectrum.

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