Geopsy: Fast Fourier Transform - Revision history

Marc at 13:31, 12 March 2010

2010-03-12T13:31:12Z

Marc at 08:54, 11 March 2010

2010-03-11T08:54:35Z

Marc: Fast Fourier Transform in Geopsy moved to Geopsy: Fast Fourier Transform

2010-03-10T14:19:54Z

Fast Fourier Transform in Geopsy moved to Geopsy: Fast Fourier Transform

Marc at 14:07, 10 March 2010

2010-03-10T14:07:06Z

Marc at 13:35, 9 March 2010

2010-03-09T13:35:02Z

Salomon Hailemikael at 12:59, 9 March 2010

2010-03-09T12:59:04Z

Salomon Hailemikael: New page: All Fourier Transforms in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FF...

2010-03-09T12:45:15Z

New page: All Fourier Transforms in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FF...

New page

All Fourier Transforms in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FFTW library. Contrary to the classical Fast Fourier Transform that requires the size to be a power of 2, FFTW alghorithm accepts arbitrary input size for signals. References about FFTW are given at [http://www.fftw.org FFTW]
== References ==
[[Wikipedia:Fast_Fourier_Transform|Fast Fourier Transform]]

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 A Fourier transform does not alter the signal, i.e. an inverse transform reproduces the complete original signal without any loss. Hence, in ''geopsy'' graphical interface, a Fourier transform is not considered as a [[Geopsy: Waveform Menu|waveform processing]]. The switch from time to frequency domain and vice-versa is located in [[Geopsy: View menu|View menu]].
-When [[Geopsy: File Menu#Export|exporting]] to an [[Geopsy: Supported file formats#ASCII Multi column (rw)|ASCII Multi-column file]] (and only for that format), the current domain is taken into account. The Fourier spectrum is exported with two columns per channel (real and imaginary). The total number of lines of the produced file is approximately half of the number of samples (difference between odd and even number of samples).
+When [[Geopsy: File menu#Export|exporting]] to an [[Geopsy: Supported file formats#ASCII Multi column (rw)|ASCII Multi-column file]] (and only for that format), the current domain is taken into account. The Fourier spectrum is exported with two columns per channel (real and imaginary). The total number of lines of the produced file is approximately half of the number of samples (difference between odd and even number of samples).
 == External references ==
 [http://www.fftw.org FFTW]

← Older revision		Revision as of 08:54, 11 March 2010
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−	All [[Wikipedia: ~~fast_Fourier_Transform~~\|Fourier Transforms]] in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FFTW library. This is a highly optimized library able to handle any number of samples (not only a power of 2)	+	All [[Wikipedia: Fourier_Transform\|Fourier Transforms]] in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FFTW library. This is a highly optimized library able to handle any number of samples (not only a power of 2)

	A Fourier transform does not alter the signal, i.e. an inverse transform reproduces the complete original signal without any loss. Hence, in ''geopsy'' graphical interface, a Fourier transform is not considered as a [[Geopsy: Waveform Menu\|waveform processing]]. The switch from time to frequency domain and vice-versa is located in [[Geopsy: View menu\|View menu]].		A Fourier transform does not alter the signal, i.e. an inverse transform reproduces the complete original signal without any loss. Hence, in ''geopsy'' graphical interface, a Fourier transform is not considered as a [[Geopsy: Waveform Menu\|waveform processing]]. The switch from time to frequency domain and vice-versa is located in [[Geopsy: View menu\|View menu]].

@@ Line 1: / Line 1: @@
 All [[Wikipedia: fast_Fourier_Transform|Fourier Transforms]] in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FFTW library. This is a highly optimized library able to handle any number of samples (not only a power of 2)
-A Fourier transform does not alter the signal, i.e. an inverse transform reproduces the complete original signal without any loss. In ''geopsy'' graphical interface
+A Fourier transform does not alter the signal, i.e. an inverse transform reproduces the complete original signal without any loss. Hence, in ''geopsy'' graphical interface, a Fourier transform is not considered as a [[Geopsy: Waveform Menu|waveform processing]]. The switch from time to frequency domain and vice-versa is located in [[Geopsy: View menu|View menu]].
 == External references ==
 [http://www.fftw.org FFTW]

@@ Line 1: / Line 1: @@
-All Fourier Transforms in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FFTW library. Contrary to the classical [[Wikipedia: fast_Fourier_Transform|Fast Fourier Transform]] that requires the size to be a power of 2, FFTW alghorithm accepts arbitrary input size for signals.
+All [[Wikipedia: fast_Fourier_Transform|Fourier Transforms]] in geopsy are based on the algorithms developed by Matteo Frigo and Steven G. Johnson (MIT) called the "Fastest Fourier Transform in the West" and encapsulated in FFTW library. This is a highly optimized library able to handle any number of samples (not only a power of 2)
 == External references ==
 [http://www.fftw.org FFTW]

← Older revision	Revision as of 14:19, 10 March 2010
(No difference)