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Re: Need some help -- plot fast fourier transform

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On Saturday, November 21, 2015 at 5:43:09 AM UTC-5, Karl-Friedrich Ratzsch wrote:
> Am 21.11.2015 um 05:56 schrieb dakupoto@gmail.com:
> > Could some Gnuplot guru please provide any simple 
> > example script for plotting FFT(fast fourier 
> > transform). Currently I am just able to create 
> > scatter plots of FFT output, but I would much
> > rather have the simple line graphs. All hints/
> > suggestions would be greatly appreciated - thans 
> > in advance for your help.
> 
> This doesn't explain your problem, just the direction from where it
> landed on your feet.
> 
> I'd say you don't want a guru, you want a nanny. Sorry.

The problem is self-explanatory. 
I have generated a set of Fast 
Fourier Transform values(amplitude,
phase) using a simple C language 
program, and the implementation is 
based on the steps described in 
Numerical Recipes in C. The C 
language program is compiled with 
GCC, running on a Fedora 18 machine. 
If I start gnuplot, and use use 
the command line 
plot 'testout' using 1:2 with lines; 
I get a beautiful symmetrical flower 
like pattern in the plot window NOT 
the set of symmetrical spikes 
associated with a spectrum.
I have used Gnuplot for years, with 
no complaints. I tried other commamds
as:
plot 'testout' using 1:2 pt 5 ps 7
and now I get a set of symmetrical 
little squares in the plot window,
where each square represents the 
peak of each spike, but I DO NOT 
see the spikes. So, obviously 
there must be some other commands
that I need to use, which I do not
know. May I know what these other
commands are ?
I am sure I have explained the problem
clearly. I expect  meaningful response.
   

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Thread

Need some help -- plot fast fourier transform dakupoto@gmail.com - 2015-11-20 20:56 -0800
  Re: Need some help -- plot fast fourier transform Karl-Friedrich Ratzsch <mail.kfr@gmx.net> - 2015-11-21 11:43 +0100
    Re: Need some help -- plot fast fourier transform dakupoto@gmail.com - 2015-11-21 19:13 -0800
      Re: Need some help -- plot fast fourier transform Richard Owlett <rowlett@cloud85.net> - 2015-11-22 04:58 -0600
      Re: Need some help -- plot fast fourier transform Thomas Wagner <thomas.wagner.marl@freenet.de> - 2015-11-25 00:51 +0100
      Re: Need some help -- plot fast fourier transform Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2015-11-25 01:25 +0100
      Re: Need some help -- plot fast fourier transform drmcnelson@gmail.com - 2017-01-28 17:47 -0800
        Re: Need some help -- plot fast fourier transform John Edwards <johned0@gmail.com> - 2017-01-31 04:18 -0800
  Re: Need some help -- plot fast fourier transform Richard Owlett <rowlett@cloud85.net> - 2015-11-21 10:07 -0600
  Re: Need some help -- plot fast fourier transform drmcnelson@gmail.com - 2017-01-28 17:08 -0800

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