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/* -*- c++ -*- */
/*
* Copyright 2007,2010,2013,2018 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 "peak_detector_impl.h"
#include <gnuradio/io_signature.h>
#include <string.h>
#include <limits>
namespace gr {
namespace blocks {
template <class T>
typename peak_detector<T>::sptr
peak_detector<T>::make(float threshold_factor_rise,
float threshold_factor_fall,
int look_ahead, float alpha)
{
return gnuradio::get_initial_sptr
(new peak_detector_impl<T>(threshold_factor_rise,
threshold_factor_fall,
look_ahead, alpha));
}
template <class T>
peak_detector_impl<T>::peak_detector_impl(float threshold_factor_rise,
float threshold_factor_fall,
int look_ahead, float alpha)
: sync_block("peak_detector",
io_signature::make(1, 1, sizeof(T)),
io_signature::make(1, 1, sizeof(char))),
d_threshold_factor_rise(threshold_factor_rise),
d_threshold_factor_fall(threshold_factor_fall),
d_look_ahead(look_ahead), d_avg_alpha(alpha), d_avg(0)
{
}
template <class T>
peak_detector_impl<T>::~peak_detector_impl()
{
}
template <class T>
int
peak_detector_impl<T>::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
T *iptr = (T*)input_items[0];
char *optr = (char*)output_items[0];
memset(optr, 0, noutput_items*sizeof(char));
T peak_val = std::numeric_limits<T>::min();
int peak_ind = 0;
unsigned char state = 0;
int i = 0;
//printf("noutput_items %d\n",noutput_items);
while(i < noutput_items) {
if(state == 0) { // below threshold
if(iptr[i] > d_avg*d_threshold_factor_rise) {
state = 1;
}
else {
d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;
i++;
}
}
else if(state == 1) { // above threshold, have not found peak
//printf("Entered State 1: %f i: %d noutput_items: %d\n", iptr[i], i, noutput_items);
if(iptr[i] > peak_val) {
peak_val = iptr[i];
peak_ind = i;
d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;
i++;
}
else if(iptr[i] > d_avg*d_threshold_factor_fall) {
d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;
i++;
}
else {
optr[peak_ind] = 1;
state = 0;
peak_val = -(T)INFINITY;
//printf("Leaving State 1: Peak: %f Peak Ind: %d i: %d noutput_items: %d\n",
//peak_val, peak_ind, i, noutput_items);
}
}
}
if(state == 0) {
//printf("Leave in State 0, produced %d\n",noutput_items);
return noutput_items;
}
else { // only return up to passing the threshold
//printf("Leave in State 1, only produced %d of %d\n",peak_ind,noutput_items);
return peak_ind+1;
}
}
template class peak_detector<float>;
template class peak_detector<std::int16_t>;
template class peak_detector<std::int32_t>;
} /* namespace blocks */
} /* namespace gr */
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