Frequency is the number of occurrences of a repeating event per unit time.〔http://www.merriam-webster.com/dictionary/frequency〕 It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency. The period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency.〔http://www.merriam-webster.com/dictionary/period〕 For example, if a newborn baby's heart beats at a frequency of 120 times a minute, its period – the interval between beats – is half a second (60 seconds (i.e., a minute) divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio (sound) signals, radio waves, and light.
== Definitions ==
For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics, acoustics, and radio, frequency is usually denoted by a Latin letter ''f'' or by the Greek letter '''' or ''ν'' (nu) (see e.g. Planck's formula).
The period, usually denoted by ''T'', is the duration of one cycle, and is the reciprocal of the frequency ''f'':
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
| 翻訳と辞書 : 翻訳のためのインターネットリソース|
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.