# frequency

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Related to frequency: frequency modulation, Sound frequency

## frequency:

see harmonic motionharmonic motion,
regular vibration in which the acceleration of the vibrating object is directly proportional to the displacement of the object from its equilibrium position but oppositely directed.
; wavewave,
in physics, the transfer of energy by the regular vibration, or oscillatory motion, either of some material medium or by the variation in magnitude of the field vectors of an electromagnetic field (see electromagnetic radiation).
.

## Frequency (wave motion)

The number of times which sound pressure, electrical intensity, or other quantities specifying a wave vary from their equilibrium value through a complete cycle in unit time. The most common unit of frequency is the hertz (Hz), which is equal to 1 cycle per second. In one cycle there is a positive variation from equilibrium, a return to equilibrium, then a negative variation, and return to equilibrium. This relationship is often described in terms of the sine wave, and the frequency referred to is that of an equivalent sine-wave variation in the parameter under discussion. See Frequency measurement, Sine wave, Wave motion

## frequency

Symbol: f , ν. The number of oscillations per unit time of a vibrating system. Frequency is measured in hertz. The frequency of a wave is the number of wave crests passing a point per unit time. For light and other electromagnetic radiation, it is related to wavelength λ by ν = c /λ, where c is the speed of light.

## Frequency

The frequency of an event A is the ratio m/n of the number m of occurrences of A in a given series of trials to the total number n of trials. If the trials are independent and there is a definite probability p of the occurrence of A in an individual trial, then, for arbitrarily small ∊ > 0, at sufficiently large m it is practically certain that the frequency m/n satisfies the inequality

(seeLARGE NUMBERS, LAW OF and PROBABILITY).

The term “frequency” is used in mathematical statistics to designate the number of elements of a set that have a specified attribute.

## frequency

[′frē·kwən·sē]
(physics)
The number of cycles completed by a periodic quantity in a unit time.
(statistics)
The number of times an event or item falls into or is expected to fall into a certain class or category.

## frequency

The number of oscillations per second (a) of the current or voltage in an alternating-current electric circuit, or (b) of a sound wave, or (c) of a vibrating solid object; expressed in hertz (abbr. Hz) or in cycles per second (abbr. cps).

## frequency

i. The number of recurrences of a periodic phenomenon in a unit of time.
ii. The number of cycles completed in one second. One cycle per second is the basic unit of measurement of frequency and is called a hertz.
iii. The number of services operated by an airline per day or per week over a particular route.

## frequency

1. Physics the number of times that a periodic function or vibration repeats itself in a specified time, often 1 second. It is usually measured in hertz.
2. Ecology
a. the number of individuals of a species within a given area
b. the percentage of quadrats that contains individuals of a species

## frequency

The number of oscillations (vibrations) in one second. Frequency is measured in Hertz (Hz), which is the same as "oscillations per second" or "cycles per second." For example, the alternating current in a wall outlet in the U.S. and Canada is 60Hz. Electromagnetic radiation is measured in kiloHertz (kHz), megahertz (MHz) and gigahertz (GHz). See wavelength, frequency response, audio, carrier and space/time.

Frequency The frequency is the number of oscillations per second. The higher the frequency (the closer the ripples would be in this diagram) and the shorter the wavelength.
References in periodicals archive ?
Running with automatic frequency steps, the duration, deflection, starting and final frequency, as well as the amount of steps, can be set.
As a set, the defective components have a lower average frequency and a broader distribution because they represent an out-of-control process state.
It is the square root of the power spectral density of magnetic field fluctuations at the magnetometer frequency.
AAF is a frequency-boosting scheme using a first-order zero (s) up to the maximum frequency of the digital information, attenuating higher frequencies that do not carry information to reduce noise.
Distortion-product otoacoustic emissions in humans with high frequency sensorineural hearing loss.
If each device needs a different frequency, there may not be enough frequencies to go around.
Typical a-c frequency drives are limited to point-to-point movement and are not capable of complex motions, says AEC's Schmitz.
The emissions comparisons estimates showed highly favorable CO2 results for flywheel-based frequency regulation.
The measurement system has been optimized so that parasitic instrument resonances occur above the maximum measurement frequency of 1,000 Hz.
The value of a standard capacitor may vary slightly with frequency because the imperfect medium between its electrodes has varying degrees of dielectric relaxation over the frequency range and the leads and electrodes of the capacitor have residual inductance.
In 1994, the company was the first to commercialize the SIEGET 25 family of ultra-high-frequency transistors with a cut-off frequency (fT) of 25 GHz.
Frequency Method - With the introduction of the solid state power supply, an inductor could be designed to operate at a frequency other than 60 Hertz (Hz).

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