“frequency”的概念、定义、翻译、参考文献-科学参考

frequency

Physics

Symbol f or ν‎. The rate of repetition of a regular event. The number of cycles of a wave, or some other oscillation or vibration, per second is expressed in hertz (cycles per second). The frequency (f) of a wave motion is given by f=c/λ‎, where c is the velocity of propagation and λ‎ is the wavelength. The frequency associated with a quantum of electromagnetic energy is given by f=E/h, where E is the quantum’s energy and h is the Planck constant.

Astronomy

The number of waves (or some other regularly repeating event) per second. Frequency is expressed in hertz (Hz). For electromagnetic radiation it is equal to the speed of the waves (c) divided by their wavelength, λ‎. See also Electromagnetic Spectrum.

Space Exploration

The number of periodic oscillations, vibrations, or waves occurring per unit of time. The SI unit of frequency is the hertz (Hz), one hertz being equivalent to one cycle per second. Frequency is related to wavelength and velocity by the equation: f = v/λ where f is frequency, v is velocity, and λ is wavelength. Frequency is the reciprocal of the period T: f = 1/T.
At one end of the electromagnetic spectrum are long radio waves with a frequency in the range 10⁴−10⁵ Hz, and at the other extreme are gamma-rays with a frequency in the range 10¹⁹−10²² Hz.
Frequency modulation (FM) is a method of transmitting radio signals in which the frequency of the carrier wave is changed and then decoded.
One kilohertz (kHz) equals 1 000 hertz; one megahertz (MHz) equals 1 000 000 hertz.

Statistics

1. The number of times that a particular data value is obtained in a sample. For example, the frequency of 5 in the sample 4, 6, 5, 7, 4, 5, 2, 5 is 3. The sum of the frequencies is the sample size. The term is also used in connection with a set of values. For example, the number of people aged between 20 and 30, or the number of people with blue or green eyes. The term relative frequency is used for the ratio (frequency) ÷ (sample size). In the context of a goodness-of-fit test, a frequency is referred to as an observed frequency and usually denoted by O, or f_O.
2. In the context of a time series, the number of cycles per unit time.

Science and Technology

The number of times that a regularly-repeating event occurs during a specified time. The unit of frequency is the hertz (Hz), 1 Hz being a frequency of one repeat per second. The frequency of rotational motion, e.g. of an engine, is often measured as revolutions per minute (rpm), thus 60 rpm = 1 Hz.
Mike Allaby

Chemical Engineering

A statistical number of occurrences within a defined interval. Used in a risk analysis, it is the number of occurrences of an event happening per unit time.

Computer

The number of complete cycles of a periodically variable quantity, such as a pulse or wave, that occurs in unit time. It is measured in hertz.

Internet

The number of oscillations per second made by an electromagnetic wave. It is measured in hertz.

Geology and Earth Sciences

The number of complete wavelengths which pass a given point in a specified time; units are hertz (Hz; one hertz is one cycle per second). The frequency of a periodic wave-form is given by f = 1/T, where T is the period; and by f = v/λ‎, where v is the velocity and λ‎ the wavelength.

单词	frequency
释义	frequency Physics Symbol f or ν‎. The rate of repetition of a regular event. The number of cycles of a wave, or some other oscillation or vibration, per second is expressed in hertz (cycles per second). The frequency (f) of a wave motion is given by f=c/λ‎, where c is the velocity of propagation and λ‎ is the wavelength. The frequency associated with a quantum of electromagnetic energy is given by f=E/h, where E is the quantum’s energy and h is the Planck constant. Astronomy The number of waves (or some other regularly repeating event) per second. Frequency is expressed in hertz (Hz). For electromagnetic radiation it is equal to the speed of the waves (c) divided by their wavelength, λ‎. See also Electromagnetic Spectrum. Space Exploration The number of periodic oscillations, vibrations, or waves occurring per unit of time. The SI unit of frequency is the hertz (Hz), one hertz being equivalent to one cycle per second. Frequency is related to wavelength and velocity by the equation: f = v/λ where f is frequency, v is velocity, and λ is wavelength. Frequency is the reciprocal of the period T: f = 1/T. At one end of the electromagnetic spectrum are long radio waves with a frequency in the range 10⁴−10⁵ Hz, and at the other extreme are gamma-rays with a frequency in the range 10¹⁹−10²² Hz. Frequency modulation (FM) is a method of transmitting radio signals in which the frequency of the carrier wave is changed and then decoded. One kilohertz (kHz) equals 1 000 hertz; one megahertz (MHz) equals 1 000 000 hertz. Statistics 1. The number of times that a particular data value is obtained in a sample. For example, the frequency of 5 in the sample 4, 6, 5, 7, 4, 5, 2, 5 is 3. The sum of the frequencies is the sample size. The term is also used in connection with a set of values. For example, the number of people aged between 20 and 30, or the number of people with blue or green eyes. The term relative frequency is used for the ratio (frequency) ÷ (sample size). In the context of a goodness-of-fit test, a frequency is referred to as an observed frequency and usually denoted by O, or f_O. 2. In the context of a time series, the number of cycles per unit time. Science and Technology The number of times that a regularly-repeating event occurs during a specified time. The unit of frequency is the hertz (Hz), 1 Hz being a frequency of one repeat per second. The frequency of rotational motion, e.g. of an engine, is often measured as revolutions per minute (rpm), thus 60 rpm = 1 Hz. Mike Allaby Chemical Engineering A statistical number of occurrences within a defined interval. Used in a risk analysis, it is the number of occurrences of an event happening per unit time. Computer The number of complete cycles of a periodically variable quantity, such as a pulse or wave, that occurs in unit time. It is measured in hertz. Internet The number of oscillations per second made by an electromagnetic wave. It is measured in hertz. Geology and Earth Sciences The number of complete wavelengths which pass a given point in a specified time; units are hertz (Hz; one hertz is one cycle per second). The frequency of a periodic wave-form is given by f = 1/T, where T is the period; and by f = v/λ‎, where v is the velocity and λ‎ the wavelength.
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