Geopsy: Correlations
Revision as of 13:39, 11 March 2010 by Clotaire Michel (talk | contribs) (New page: thumb|right|200px|Correlations pop-up window '''Correlations''', reached from the Waveform menu, computes the correlations of the sign...)
Correlations, reached from the Waveform menu, computes the correlations of the signals in the active signal viewer with the requested signals.
Parameters
By clicking on Correlations, a pop-up window appears with the following options:
- Maximum time delay controls the size of the output window. The value m is in seconds. The correlations are displayed between -m and +m.
- Choice of the signal to correlate with the active signals. The possibilities are:
- Between all pairs of signals will compute all the parts of the correlation matrix, i.e. the correlation of each signal of the active signal viewer with each other.
- With a reference signal will compute the correlation of each signal of the active signal viewer with the selected signal in the combo box (one line of the correlation matrix). It is only possible to correlate the signals with one of them.
Correlations modifies the temporary signal.
Warning: The correlation of signals with a different starting and ending times cannot be computed. First cut the signals.
Use of correlation
Correlation between 2 signals (c.f. Cross-Correlation) is able to give many different informations. First, the maximum in time gives the time delay between two signals. The spectra of the cross-correlations is the cross-power spectra. It enhances the frequencies common to the two signals.
