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Expanded Description
Topic Description
Name
filter
Synopsis
/infobank/programs/filt/filter/filter.for
Description
  Program to filter single fields.  

   
  Assumes evenly spaced data.
  Driver for FILTERIT subroutines by Robert Walraven (U.C. Davis).
       
PROMPTS
  Enter input file name:

  no filtering --     lower = 0          upper = 1
  low pass     --     lower = 0      0 < upper 
  high pass    -- 0 < lower < 1          upp
  band pass    --       0 < lower < upp
  band stop    --       0 < upper < low
  Enter LOWER frequency of filter:
  Enter UPPER frequency of filter:
  Enter size of Gibbs phenomenon (50 is usually good):
  SHOWCOEF calculates number of points (order) in filter =
  Designate the REAL field you want filtered (a,f,a):
                                        ex:  (a36,f8.2,a32)
  XXXX = lower filter limit
  XXXX = upper filter limit
  XXXX = Gibbs value
  XXXX = # points (order) in filter
  Enter input  file name:
  Enter output file name:
    
SUBROUTINES
  vesc       (external include)

  openem     (external shareable)
  howlong    (external shareable)
  showcoef   (external)
  showlines  (external shareable)
  whatfmt    (external shareable)
  filterit   (external)
    
AUTHOR
  Clint Steele              .for             12/26/84

  Modified by Carolyn Degnan, 03/07/85
  to handle our new headers upon second pass thru input file.
  Modified by Carolyn Degnan, 09/05/86
  to use the # points (order) suggested by SHOWCOEF
  instead of prompting for it
    
SEE_ALSO
  besio

  filterit

    
Reads
      read (5,*) flow
      read (5,*) fhigh
      read (5,*) gibbs
      read (*, '(a)') fmt
          read (90, fmt, end = 99) ain, yin(icount), bin
          read (90, fmt) ain, garbage, bin
Writes
          write (91, fmt) ain, yin(jcount), bin
Opens
Calls
      call openem (1,0)
      call showcoef (flow, fhigh, gibbs, iorder, percent)
      call showlines (90,5)
      call showcoef (flow, fhigh, gibbs, iorder, percent)
      call filterit (yin, yin, icount,
     *               flow, fhigh, gibbs,
     *               nterms, iflag)
      call openem ( 1, 1 )
          call kaiser (coef, nterms, a)
      call const ( norder, fcut1, fcut2, itype, acheb )
          call pole ( ii, norder, itype, acheb )
          call trnsfm ( ii, norder )
          call nxttrm ( a, b, ii, norder )
      call rfltlw (n, f, ikind, y, z, npts)
      call rfltlw (n, fhigh, ikind, y, z, npts)
      call kaiser ( coef, nterms, a )
          call kaiser (coef, icount, gibbs)

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URL: http://walrus.wr.usgs.gov/infobank/programs/filt/filter/filter.doc.html
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Page Last Modified: Mon Sep 16 03:37:06 PDT 2013  (chd)