Goniometer

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The goniometer (from Greek  γωνία Goniá , "angle" and μέτρον métron , "degree (measuring tool, then the measured) even meter ") is a measuring instrument for the determination of angles , and the electrical phase angle at the stereophony .

Versions for measuring angles

Simple medical goniometer
Mineralogical goniometer, around 1800
A two-circle goniometer as used in crystallography. The reading accuracy on the partial circles is better than a minute of arc .

There are different versions, adapted to the respective purpose.

The simplest goniometer is a protractor with two movable arms between which a scale is attached for reading angles. This measures z. B. in medicine joint angles or the position of the skull bones, in crystallography the angle between crystal surfaces by placing the two legs.

The fitting goniometer was used by the French crystallographer Jean-Baptiste Romé de L'Isle and his assistant Carangeot as early as 1780 . In 1809 Wollaston developed the reflection goniometer which, with the help of a light beam reflected on the crystal surfaces, enables angle measurements with very high accuracy.

In geodesy , more complex devices are often used, with which u. a. can measure other optical instruments. A simple device for mapping measured points is the conveyor , in which a protractor is provided with a scale for plotting the points. There are similar devices for navigation .

Version for measuring the phase position in stereophony

In sound recording technology in stereophony , the goniometer is important as a display of the phase position of the audio signals or the similarity between the two channels L and R. This avoids the prevalence of partially out of phase and reverse polarity signals, which would otherwise be canceled out when listening in mono.

Individual evidence

  1. ↑ Will. Hyde Wollaston: A reflection goniometer invented and described by. In: Annals of Physics . NF Vol. 7 = Vol. 37, No. 4, 1811, pp. 357-364, doi : 10.1002 / andp.18110370402 .

literature

  • Thomas Görne: Sound engineering. Fachbuchverlag Leipzig in Carl Hanser Verlag, Munich et al. 2006, ISBN 3-446-40198-9 .

See also

Web links

Commons : Goniometer  - collection of images, videos and audio files
Wiktionary: Goniometer  - explanations of meanings, word origins, synonyms, translations