fir_interp.h

Go to the documentation of this file.

#ifndef FIRI
#define FIRI
#include <fir.h>
// 
// 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.
*/
namespace SPUC {


template <class Numeric> class fir_interp : public fir<Numeric>
{
        public: 
        long num_low;
    long rate;    
    long phase;   
        long auto_mode; 
    
    public: 
    void skip() { phase++; phase = phase%rate; }; 
        void set_rate(long r) { rate = r; num_low = (fir<Numeric>::num_taps/r - 1);}
        void set_automatic(void) { auto_mode = 1;};
        void set_manual(int def_phase=0) { auto_mode = 0; phase=def_phase;};


    fir_interp<Numeric>(const char* i) : phase(0), auto_mode(1), fir<Numeric>(i) {      };
    fir_interp<Numeric>(void) : phase(0), auto_mode(1) {        };
        fir_interp<Numeric>(long n) : phase(0), auto_mode(1),
                fir<Numeric>(n) {       };
        void reset() {
                fir<Numeric>::reset();
                phase = 0;
        }
        Numeric coeff_sum() { return(fir<Numeric>::coeff_sum()); }
    void input(Numeric in) {
                int i;                                           
                // Update history of inputs
                for (i=num_low;i>0;i--) fir<Numeric>::z[i] = fir<Numeric>::z[i-1];  
                // Add new input
                fir<Numeric>::z[0] = in;   
        }
        Numeric clock(long set_phase) {
                phase = set_phase;
                return(clock());
        }
        Numeric clock(void) {
                // Perform FIR
                Numeric output;
                int i;
                for (output=0,i=0;i<num_low;i++) {
                        output += fir<Numeric>::coeff[(i+1)*rate+phase]*fir<Numeric>::z[i];
                }
                // Increment to next polyphase filter
                if (auto_mode) phase++;                                       
                phase = phase%rate;
                return(output); 
        }

};      
} // namespace SPUC 
#endif

---