NAME

     diffr - differentiate (integrate) trace data

SYNOPSIS

     diffr [ -Nntap ] [ -Ootap ] [ -rsirs ] [ -reire ]  [  -ityp-
     weighting  type  ] [ -fuupper frequency ] [ -dbaccuracy cri-
     teria ] [ -nordorder of the derivative ] [ -I ] [ -V ] [  -?
     ]

DESCRIPTION

     diffr in differentiation mode: designs an optimal  differen-
     tiation  operator  for a user defined upper frequency, accu-
     racy criteria and smoothing function type. The  operator  is
     convolved  with  input  data  traces  to acheive a specified
     derivative order. A 48 ms ramp is applied to the end of each
     trace  to  attenuate  edge  effects from the differentiation
     operator being convolved off the trace end. The differentia-
     tion  operator's  amplitude  spectrum will be accurate to an
     upper frequency  specified  by  the  user  which,  generally
     should  be  less  than  95 percent of the Nyquist frequency.
     Program diffr is based on K. L. Peacock's DIFI subroutine.

     diffr in integration mode: computes a simple running sum  of
     the trace.

     diffr gets both its data and  its  parameters  from  command
     line arguments.

  Command line arguments
     -Nntap
          Enter the input data set name or file immediately after
          typing  -N;  entering  nothing  specifies a stdin pipe.
          This input put 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 'vsp' stored on the 'b' disk.

     -Ootap
          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).

     -rs irs
          (integer) First record to process (default = 1)

     -re ire
          (integer) Last record to process (default = all)

     -itypweighting function type
          Differentiation option: enter  the  type  of  weighting
          fuction  to be used in smoothing the operator. Either a
          Ross (ROSS) or Bessel (BESS) function  can  be  chosen.
          (default=BESS)

     -fuupper frequency
          Differentiation option: enter the upper frequency  (hz)
          the   differential   operator   will  be  accurate  to.
          (default=60)

     -dbaccuracy criteria
          Differentiation option:  enter  the  accuracy  criteria
          (dB)  the  upper  frequency  will  be designed to meet.
          (default=40)

     -nordderivative order
          Differentiation option: enter the order of the  deriva-
          tive (default=1, set to -1 if I option invoked below)

     -I   Enter the command line  argument  '-I'  to  invoke  the
          integration option (this will override the -nord option
          above).

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

     -?   Enter this (or '-?' if you are running in  c-shell)  to
          get  online  help.   The  program  will terminate after
          printing this.

COPYRIGHT

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