bfil

NAME
SYNOPSIS
DESCRIPTION
FILES
SEE ALSO
BUGS
COPYRIGHT
AUTHOR

NAME

bfil - BSU program which applies an ARMA filter in the time domain

SYNOPSIS

bfil [ -h | infile | itype | npoles | fcenter | bwidth | ifaz ]

DESCRIPTION

Basic Seismic Utilities (BSU) filters seismic traces in the time domain with an ARMA operator. Either minimum-phase or zero-phase filters may be realized, the latter by the usual time reversal trick. Filters are designed in the Laplace Transform domain and then converted to Z-transform with a Bilinear Transform. While the basic design is for 2-poles, the algorithm achieves higher order filters by simply cascading the sampe filter (stacking poles on top of each other, but the pole locations are adjusted to maintain the desired cut-off frequencies). Filter design details (both in the S-plane and Z-plane) as well as frequency response and impulse response plots are provided in the listing file. Code is Fortran 77.

Options

-h

Online help giving details on command line arguments

infile

Input file name

itype

Switch to select filter type.

0=low-pass

1=band-pass

2=high-pass

npoles

Number of poles in the filter (even number)

fcenter

Center frequency of filter.

bwidth

Band width of filter (cut-off frequencies= fcenter +/- bwidth/2)

WARNING: Only include bandwidth for BANDPASS filter, itype=1 (or else will abort)

ifaz

Switch to select filter phase property.

0=zero-phase (forward-reverse trick)

1=minimum phase

NOTE:
If invoked with no options, will prompt user for input parameters.

EXAMPLE:
bfil twave.seg 0 12 200. 1

Data are filtered by a 200 Hz low-pass filter, minimum phase. Note that the bandwidth SHOULD NOT be specified on the command line unless a band-pass filter is selected (itype=1).

FILES

bfilxxxx.seg

Named according to convention (first 4char bfil, the next 4char are the first 4char of the input file name, suffix .seg)

standard output

produces a progress bar

bfilxxxx.lst

echo check of input parameters

SEE ALSO

bhelp(1)

BUGS

No known bugs

COPYRIGHT

Copyright © 2024 by Paul Michaels

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

AUTHOR

P. Michaels, PE. <paulmichaels@.boisestate.edu>