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Re: Fast Fourier Transforms

• To: mathgroup at smc.vnet.net
• Subject: [mg21635] Re: Fast Fourier Transforms
• From: cs106 at waii.com (Randy Winney)
• Date: Tue, 18 Jan 2000 02:35:20 -0500 (EST)
• Organization: Western Geophysical
• References: <85p7u3$6je@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

In article <85p7u3$6je at smc.vnet.net>, "Burton" <Ctheurer at ecs.umass.edu> writes:
|>     I am doing some analysis of acoustic data obtained from a pickup located
|> on a machine.  The data is in the form of ordered pairs i.e. Time and
|> voltage.  As far as I know fft in Mathematica only operates on a list of
|> single numbers.  I have imported the voltage data (since the time is simply
|> incremental) and performed an fft on that successfully.  My problem lays in
|> interpreting this data.  I don't understand how to scale the x-axis of the
|> fft plot to represent frequency.
|>     Any suggestions would be appreciated.

My guess would be DC (0 Hz) to Nyquist (1/(2 * temporal_sample_rate_in_seconds))

--
Randy Winney                                   randy.winney at westgeo.com
Seismic Processing Software Development        713.689.2487
Western Geophysical
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