An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 3 Search : beat
beat
  زنش   
zaneš (#)

Fr.: battement   

The periodic and alternatively strengthening and weakening of two waves of similar frequencies when they interfere with one another. In particular, the soft and loud sounds created by the interference of two sound waves of similar frequencies.

M.E. beten, from O.E. beaten, from P.Gmc. *bautan; IER *bhau- "to strike."

Zaneš, noun from zan- present tense stem of zadan "to beat, strike" + verbal noun suffix. Zadan from Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- "to strike, hit, smite, kill" (jantar- "smiter"); cf. Skt. han- "to strike, beat" (hantar- "smiter, killer"); Gk. theinein "to strike;" L. fendere "to strike, push;" Gmc. *gundjo "war, battle;" PIE *gwhen- "to strike, kill."

beat Cepheid
  کِفِیءوسی ِ زنشی   
kefeusi-ye zaneši

Fr.: céphéide à battement   

A Cepheid variable in which two or more almost identical periods of variability pass into and out of phase with each other, producing periodic amplitude fluctuations in their light curves. Beat periods are typically about 2 hours.

beat; → Cepheid.

beat frequency
  بسامد ِ زنش   
basâmad-e zaneš

Fr.: fréquence de battement   

One of the frequencies that results from the combination of two waves of slightly different frquencies. A beat frequency is equal to the absolute value of the difference between the two frequencies. An unknown frequency can be determined by beating it with a reference frequency. More specifically, when the two frequencies are superimposed, the phase difference will change with time and wave interference alternate between constructive and destructive. The alterations of intensity brings about a beat frequency.

beat; → frequency.