Goniometer
The goniometer (from Greek γωνία Gonia, " angle" and μέτρον métron, " measure ( measuring tool, then the Measured ), also verse ") is an instrument for measuring angles, as well as the electrical phase angle at the Stereophonic sound.
Embodiments for the measurement of angles,
There are different versions, adapted to the particular application.
The simplest goniometer is a protractor with two movable arms, between which a scale is attached to Winkelablesen. In order to measure, for example, in medicine joint angle or the position of the cranial bones, in crystallography the angle between crystal faces by applying the two legs.
The Anlegegoniometer has already been used in 1780 by the French crystallographer Jean -Baptiste Romé de L'Isle and his assistant Carangeot. 1809 developed the Wollaston Reflexionsgoniometer that allows using a reflected at the crystal faces light beam angle measurements with very high accuracy.
In geodesy, often more sophisticated devices are used, among other things with which one can measure other optical instruments. A simple device for the mapping of points is measured, the carrier, wherein a goniometer is provided with a scale for the application scale of the points. Similar devices are available for navigation.
The goniometer to measure the phase angle at the stereophonic
In the sound recording technology in the stereophonic has the goniometer, which is also called stereo vision device or correlation meter, its importance as an indicator of the phase position of the audio signals or the similarity between the two channels L and R. Thus, a prevalence of partial anti-phase and reverse-polarity signals is avoided, would otherwise be wiped out when mono- Listen. The goniometer is essentially a oscilloscope tube, the axes of which are in this case rotated through 45 ° mechanically, that an L R signal, which is a sum signal or center, vertical display from the top down. A sole left signal shows a 45 ° angle to the left and a right signal to the right as well.
Assuming a normal oscilloscope and includes the L signal to the X input and the R signal to the vertical input, then results in a mono signal L = R and phase 0 ° a 45 ° inclined to the right line. The display tube then needs to be mechanically rotated by 45 °. An often proposed to in textbooks matrix for M- and S- transformation of the L and R signals is therefore not necessary for an oscilloscope as a goniometer.