NAME

     rwdft  - Spectral decomposition of a single or multiple fre-
     quencies via running window discrete Fourier transform.

SYNOPSIS

     rwdft [ -Nntap ] [ -Ootap ] [ -sstart ] [ -eend ] [ -fminmin
     freq  ] [ -fmaxmax freq ] [ -fintfreq increment ] [ -winwin-
     dow length ] [ -tapercosine taper ] [  -nstrace  start  ]  [
     -netrace  end ] [ -rsrecord start ] [ -rerecord end ] [ -G ]
     [ -V ] [ -? ]

DESCRIPTION

     rwdft Performs a spectral decomposition on seismic data  for
     a  single  or multiple user defined frequency with the  user
     defined sliding window which can have  a Gaussian or  cosine
     taper  on  a range of samples defined by start and end times
     of selected traces or ranges of traces with a user specified
     value.   Output  is  an  sis format file of the user defined
     spectral decomposition. Output is both amplitude then  phase
     spectra,  with  N  records  for  each input record where N =
     number of frequencies.

     rwdft gets both its data and  its  parameters  from  command
     line  arguments.  These arguments specify the input, output,
     the operator window, the percent of cosine taper,  and  ver-
     bose printout, if desired.

  Command line arguments
     -N ntap
          Enter the input data set name or file immediately after
          typing -N unless the input is from a pipe in which case
          the -N entry must be omitted.  This input  file  should
          include the complete path name if the file resides in a
          different directory.  Example -N/b/vsp/dummy tells  the
          program to look for file 'dummy' in directory '/b/vsp'.

     -O otap
          Enter the output data  set  name  or  file  immediately
          after typing -O.  This output file is not required when
          piping the output to another process.  The output  data
          set also requires the full path name (see above).

     -s start time
          Enter the global start time  of the spectral decomposi-
          tion.  Default = trace start.

     -e end time
          Enter the global end time of  the  spectral  decomposi-
          tion.  Default = trace end.

     -win window
          Enter the window operator length.  Default = 32

     -fmin min frequency
          Enter the minimum frequency (hz) value of  the  desired
          analysis.  Default=0

     -fmax max frequency
          Enter the maximum frequency (hz) value of  the  desired
          analysis. Default = nyquist.

     -fint frequency interval
          Enter the frequency interval for the analysis.  Default
          = 1 hz.

     -taper percent taper
          Enter the percent of cosine taper .  Default = 0.0

     -ns trace start
          Enter the first record number for analysis   Default  =
          1.0

     -ne trace end
          Enter the last trace number for analysis  Default = end
          of data

     -rs recored start
          Enter the first record number for analysis   Default  =
          1.0

     -re record end
          Enter the last record number for  analysis   Default  =
          end of data

     -G   Enter the command line argument '-G' to get a  Gaussian
          taper.

     -V   Enter the command line argument '-V' to get  additional
          printout.

     -?   Enter the command line  argument  '-?'  to  get  online
          help.   The program terminates after the help screen is
          printed.

BUGS

     unknown

AUTHOR

     James M. Gridley, Greg Partyka and Joe 'Da Man'  Wade  (he's
     still a putz).

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.