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graphing frequency & amplitude?

• To: mathgroup at smc.vnet.net
• Subject: [mg79153] graphing frequency & amplitude?
• From: efifer at fas.harvard.edu
• Date: Fri, 20 Jul 2007 03:16:20 -0400 (EDT)

Hi,

I am trying to create a graph that graphs frequency versus amplitude of a sound
made by the sum of two sine waves. I tried fourier transforming them and
graphing it, yet it looks to me like the graph is plotting time rather than
frequency. How do I change this?

Plot[10*Sin[200t] + 10*Sin[100t], {t, 0, 1}]

data = Table[10*Sin[200t] + 10*Sin[100t], {t, 0, 100}]

ListPlot[Abs[Fourier[data]], PlotJoined -> True, PlotRange -> All]

Thank you for the help!
Emily

• Follow-Ups:
  • Re: graphing frequency & amplitude?
    • From: Sseziwa Mukasa <mukasa@jeol.com>