iir_comb.h

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// 
// Copyright(c) 1993-1996 Tony Kirke
// author="Tony Kirke" *
/*
 * SPUC - Signal processing using C++ - A DSP library
 * 
 * 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, 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.
*/
#ifndef IIR_COMB
#define IIR_COMB
#include <delay.h>
namespace SPUC {
template <class Numeric> class iir_comb {
 protected:   
        double in_gain;                    
        double acc_gain;                    
        Numeric out;
        delay<Numeric> dly;
        long delay_size;
        Numeric previous_out;
        Numeric previous_in;
        
 public:
        iir_comb(double A=0, long delay=2) : acc_gain(A), in_gain(1-A),
                delay_size(delay) {
                dly.set_size(delay);
                previous_in = previous_out = out = 0 ; 
        }
        void init(double A, long delay) { 
                in_gain=1-A; acc_gain = A;
                delay_size = delay;
                dly.set_size(delay);
        }

        void set_coeff(double A) { in_gain=1-A; acc_gain = A;}
        Numeric clock(Numeric input) {
                // Shift previous outputs and calculate new output
                out = acc_gain*previous_out + in_gain*input;
                previous_out = dly.input(out);
                return(out);
        }
        void reset() {
                previous_in = previous_out = out = 0;
                dly.reset();
        }
};                                               
} // namespace SPUC 
#endif

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