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A correlator performs the function of cross-correlation for the precise determination of the time offset between two signals. Possible forms are special computers, analog circuits , brain structures or computer programs . The signals can be technically coded radio signals , radar , sonar or optical echoes or signals of natural origin.

The principle is explained using three different applications as an example,

In the correlation, two signals are shifted against each other by calculation until the characteristics of the two signals match. The shift found is then the time difference

  • either between the transit times from a radiation source (quasar) to two ground stations
  • or the signals of the two sensors that move one after the other over a structure
  • or between the code received from a satellite and the code calculated in the receiver.

As long as the radiolocation receiver after switching (position-dependent!) The orbits of satellites and knows his own movement in space only very roughly, his correlators have because of the Doppler shift signals not only time- shifting , but also different stretch . This two-dimensional search is considerably more complex.

Correlators in comparison

See also

Individual evidence

  1. Powerful Supercomputer Makes ALMA a Telescope .
  2. ↑ The highest supercomputer in the world compares astronomy data . Heise online.
  3. a b Cross-Correlators & New Correlators - Implementation & choice of architecture . (PDF; 9.4 MB) National Radio Astronomy Observatory, p. 27.
  4. ^ The Expanded Very Large Array Project - The 'WIDAR' Correlator . (PDF; 13.2 MB) National Radio Astronomy Observatory, p. 10.