timedomain_filt_vector.c 2.14 KB
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/*-----------------------------------------------------------------------------------------
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 * Copyright (C) 2016  For the list of authors, see file AUTHORS.
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 *
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 * This file is part of IFOS.
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 * 
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 * IFOS is free software: you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 2.0 of the License only.
 * 
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 * IFOS is distributed in the hope that it will be useful,
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 * 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
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 * along with IFOS. See file COPYING and/or <http://www.gnu.org/licenses/gpl-2.0.html>.
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-----------------------------------------------------------------------------------------*/

/*------------------------------------------------------------------------
 *   Filter seismograms in time domain with a Butterworth filter
 *   Lowpass or highpass filtering can be applied                                  
 *  ----------------------------------------------------------------------*/
#include "fd.h"
#include "segy.h"
#include "cseife.h"

void  timedomain_filt_vector(float * data, float fc, int order, int ntr, int ns, int method){

	/* 
	data	: 	2-dimensional array containing seismograms (
	fc	:	corner frequency in Hz
	order	:	order of filter
	ntr	:	number of traces
	ns	:	number of samples
	method	:	definition of filter
			1: lowpass filter
			2: highpass filter
	*/
			

	/* declaration of extern variables */
	extern float DT;
	
	/* declaration of local variables */
	int itr, j;
	double *seismogram, T0;
	
	
	
	seismogram=dvector(1,ns);
	
	T0=1.0/fc;
	
	if ((order%2)!=0){
		err("Order of timedomain filter must be an even number!");}
		
			
	
		for (j=1;j<=ns;j++){
			seismogram[j]=(double)data[j];}
		
		if (method==1){		/*lowpass filter*/
			seife_lpb(seismogram,ns,DT,T0,order);}
		
		
		if (method==2){		/*highpass filter*/
			seife_hpb(seismogram,ns,DT,T0,order);}
		
		for (j=1;j<=ns;j++){
			data[j]=(float)seismogram[j];}
	
	
	free_dvector(seismogram,1,ns);
}