xcor

NAME
SYNOPSIS
DESCRIPTION
SEE ALSO
BUGS
COPYRIGHT
AUTHOR

NAME

xcor - subroutine to perform cross correlation.

SYNOPSIS

call xcor(npts,t1,t2,tlagmx,tzero,dt,c,v,cc)

DESCRIPTION

Basic Seismic Utilities (BSU) subroutine which cross correlates input traces "c" and "v", producing output trace, "cc". With the exception of an autocorrelation, this is not a commutative process. The sense of it is that trace "c" is the moving trace, sliding past the stationary trace, "v", from left to right. This might be useful to those planning to take an FFT of the cross correlation who might make some use of the phase. It is also relevant if one is looking for relative shifts (like a static shift) between two traces. It is assumed that "c" and v" are of the same length, npts. Zero lag position is when the two signals are aligned together (complete overlap). See subroutines xcor1 (one-sided auto correlation) or cross, E.A.Robinson’s correlation subroutine for alternative codes.
Fortran Version
.

Arguments
npts (int)

Number of samples in a trace

t1 (float)

Start time for the correlation aperture (or gate). Same for both "c" and "v".

t2 (float)

End time for the correlation aperture. Same for both "c" and "v".

tlagmx (int)

Maximum relative shift from zero lag (in units of time).

tzero (float)

Time at which zero lag occurs in the output signal, "cc".

dt (float)

Sample interval in seconds.

SEE ALSO

xcor1(3), cross(3)

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>