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 ?
Under the draft, returning the assigned radio frequencies is 'voluntary' on the part of the new market player.
State Administration of Radio Frequencies exercises control over registration and operation of radio electronic equipment in the territory of Azerbaijan.
International spectrum governance involves the allocation of radio frequency bands for specific purposes and assigns radio frequencies for individual, commercial and government use.
Sistema (LSE:SSA), a public diversified corporation in Russia and the CIS, has confirmed it has received radio frequencies in two further circles in India.
These would be distinct from the set of unassigned 3G, 4G and potential 5G radio frequencies the DICT hopes to award to a new major telco player by May or June this year.
Natural resources such as oil, coal and precious metals are limited or finite and are in high demand; similarly, radio frequencies from the electromagnetic spectrum are also in high demand.
But ensuring interoperable communications is a complex process that involves a number of factors, including communications control and coordination of radio frequencies.
Research on the chemistry of vision has led to the identification of a set of compounds that absorb electromagnetic waves at radio frequencies. These compounds, called Schiff base salts, when applied to the surface of a military aircraft, may significantly lower the aircraft's tendency to reflect radar signals.
Where are radio frequencies in the electromagnetic spectrum?

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