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/* -*- c++ -*- */
/*
* Copyright 2002,2011,2012 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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 3, or (at your option)
* any later version.
*
* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <cmath>
#include <fft/goertzel.h>
namespace gr {
namespace fft {
goertzel::goertzel(int rate, int len, float freq)
{
set_params(rate, len, freq);
}
void
goertzel::set_params(int rate, int len, float freq)
{
d_d1 = 0.0;
d_d2 = 0.0;
float w = 2.0*M_PI*freq/rate;
d_wr = 2.0*std::cos(w);
d_wi = std::sin(w);
d_len = len;
d_processed = 0;
}
gr_complex
goertzel::batch(float *in)
{
d_d1 = 0.0;
d_d2 = 0.0;
for(int i = 0; i < d_len; i++)
input(in[i]);
return output();
}
void
goertzel::input(const float &input)
{
float y = input + d_wr*d_d1 - d_d2;
d_d2 = d_d1;
d_d1 = y;
d_processed++;
}
gr_complex
goertzel::output()
{
gr_complex out((0.5*d_wr*d_d1-d_d2)/d_len, (d_wi*d_d1)/d_len);
d_d1 = 0.0;
d_d2 = 0.0;
d_processed = 0;
return out;
}
} /* namespace fft */
}/* namespace gr */
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