Difference between revisions of "Geopsy: Phase shift"
Jump to navigation
Jump to search
| Line 4: | Line 4: | ||
By clicking on ''Phase shift'', a pop-up window appears asking for the time delay applied to the signals. The value is in seconds. | By clicking on ''Phase shift'', a pop-up window appears asking for the time delay applied to the signals. The value is in seconds. | ||
| − | This tool aims at delaying signals for values lower than the sampling period of the signal. The shift is done in the frequency domain by | + | This tool aims at delaying signals for values <math>\delta t</math> lower than the sampling period of the signal. The shift is done in the frequency domain by modifying the phase at each frequency according to the following formula : |
| + | <math> | ||
| + | F_{shift}(\omega) = F_{orig}(\omega).\exp(j.\omega . \delta t) | ||
| + | </math> | ||
| + | Therefore, the starting time and the number of samples are not changed. This assumes the signals are periodic, the first samples may therefore be shifted to the end of the signal. | ||
Delaying signals of higher time periods is achieved by [[Geopsy: Set header|modifying the starting time in the header information]] by the mean of generic formulas. | Delaying signals of higher time periods is achieved by [[Geopsy: Set header|modifying the starting time in the header information]] by the mean of generic formulas. | ||
''Phase shift'' modifies the [[Geopsy: Temporary Signal|temporary signals]] in the active viewer. | ''Phase shift'' modifies the [[Geopsy: Temporary Signal|temporary signals]] in the active viewer. | ||
Revision as of 16:24, 11 March 2010
Phase shift, reached from the Waveform menu, delays the signals in the active signal viewer for a given time length. By clicking on Phase shift, a pop-up window appears asking for the time delay applied to the signals. The value is in seconds.
This tool aims at delaying signals for values lower than the sampling period of the signal. The shift is done in the frequency domain by modifying the phase at each frequency according to the following formula :
Therefore, the starting time and the number of samples are not changed. This assumes the signals are periodic, the first samples may therefore be shifted to the end of the signal.
Delaying signals of higher time periods is achieved by modifying the starting time in the header information by the mean of generic formulas.
Phase shift modifies the temporary signals in the active viewer.
