Geopsy: Phase shift - Revision history

Clotaire Michel at 13:44, 12 March 2010

2010-03-12T13:44:17Z

Pierre-Yves Bard at 16:24, 11 March 2010

2010-03-11T16:24:33Z

Pierre-Yves Bard at 16:24, 11 March 2010

2010-03-11T16:24:18Z

Clotaire Michel at 15:50, 10 March 2010

2010-03-10T15:50:02Z

Clotaire Michel: New page: '''Phase shift''', reached from the Waveform menu, delays the signals in the active signal viewer for a given time length. By clicking ...

2010-03-09T13:05:30Z

New page: '''Phase shift''', reached from the Waveform menu, delays the signals in the active signal viewer for a given time length. By clicking ...

New page

'''Phase shift''', reached from the [[Geopsy: Waveform Menu|Waveform menu]], delays the signals in the active [[Geopsy: Signal Viewer|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 interpolation. 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: Edit menu#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.

← Older revision		Revision as of 13:44, 12 March 2010
Line 12:		Line 12:
	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'' create new [[Geopsy: Temporary Signal\|temporary signals]] in the active viewer.

@@ Line 8: / Line 8: @@
 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.
 ''Phase shift'' modifies the [[Geopsy: Temporary Signal|temporary signals]] in the active viewer.

@@ 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.
-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 interpolation. 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.
+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 :
 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.

@@ Line 1: / Line 1: @@
 '''Phase shift''', reached from the [[Geopsy: Waveform Menu|Waveform menu]], delays the signals in the active [[Geopsy: Signal Viewer|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.
+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 interpolation. 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: Edit menu#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.