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/* -*- c++ -*- */
/*
* Copyright 2014 Sylvain Munaut <tnt@246tNt.com>
*
* This 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.
*
* This software 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 software; 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 <stdio.h>
#include <gnuradio/io_signature.h>
#include <gnuradio/fft/window.h>
#include <volk/volk.h>
#include "rach_detect_fft_impl.h"
namespace gr {
namespace gmr1 {
rach_detect_fft::sptr
rach_detect_fft::make()
{
return gnuradio::get_initial_sptr(
new rach_detect_fft_impl()
);
}
rach_detect_fft_impl::rach_detect_fft_impl()
: gr::block("rach_detect_fft",
io_signature::make(1, 1, sizeof(gr_complex)),
io_signature::make(1, 1, sizeof(gr_complex)))
{
this->d_threshold = 8.5f; // 7.5f;
this->d_overlap_ratio = 2;
this->d_fft_size = 512;
this->d_fft = new gr::fft::fft_complex(this->d_fft_size, true, 1);
this->d_buf = (gr_complex *) volk_malloc(this->d_fft_size * sizeof(gr_complex), 128);
this->d_win = (float *) volk_malloc(this->d_fft_size * sizeof(float), 128);
this->d_pwr = (float *) volk_malloc(this->d_fft_size * sizeof(float), 128);
this->d_pos = 0;
std::vector<float> win = gr::fft::window::blackmanharris(this->d_fft_size);
memcpy(this->d_win, &win[0], this->d_fft_size * sizeof(float));
}
rach_detect_fft_impl::~rach_detect_fft_impl()
{
volk_free(this->d_pwr);
volk_free(this->d_win);
volk_free(this->d_buf);
delete this->d_fft;
}
void
rach_detect_fft_impl::peak_detect(uint64_t position)
{
const int avg_hwin = 15;
const int avg_win = (avg_hwin * 2) + 1;
float sum;
int i;
/* Prime the moving average */
sum = 0.0f;
for (i=0; i<avg_win; i++)
sum += this->d_pwr[i];
/* Do a scan and compare with avg with peak */
for (i=avg_hwin; i<this->d_fft_size-avg_hwin; i++)
{
if (this->d_pwr[i] > (this->d_threshold * sum / (float)avg_win))
printf("(%lld, %d)\n", (long long)position, i);
sum += this->d_pwr[i+avg_hwin+1] - this->d_pwr[i-avg_hwin];
}
}
int
rach_detect_fft_impl::general_work(
int noutput_items,
gr_vector_int& ninput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
int read;
/* Buffers pointer */
const gr_complex *sig_in = reinterpret_cast<const gr_complex *>(input_items[0]);
gr_complex *burst_out = reinterpret_cast<gr_complex *>(output_items[0]);
gr_complex *fft_in = this->d_fft->get_inbuf();
gr_complex *fft_out = this->d_fft->get_outbuf();
/* Process as much as we can */
for (read=0; read<noutput_items;)
{
int n_adv = this->d_fft_size / this->d_overlap_ratio;
int n_reuse = this->d_fft_size - n_adv;
int n_fill;
/* Fill our internal buffer */
n_fill = this->d_fft_size - this->d_pos;
if (n_fill > noutput_items - read)
n_fill = noutput_items - read;
memcpy(this->d_buf + this->d_pos,
sig_in + read,
n_fill * sizeof(gr_complex));
read += n_fill;
this->d_pos += n_fill;
if (this->d_pos != this->d_fft_size)
break;
/* Apply window */
volk_32fc_32f_multiply_32fc(
fft_in,
this->d_buf,
this->d_win,
this->d_fft_size
);
/* Compute FFT */
this->d_fft->execute();
/* Compute the squared power */
volk_32fc_magnitude_squared_32f(this->d_pwr, fft_out, this->d_fft_size);
/* Run the peak detection */
this->peak_detect(
this->nitems_read(0) + read - (this->d_fft_size / 2)
);
/* Handle overlap */
if (this->d_overlap_ratio > 1) {
memmove(this->d_buf, this->d_buf + n_adv, n_reuse * sizeof(gr_complex));
this->d_pos = n_reuse;
} else {
this->d_pos = 0;
}
}
/* We read some stuff */
this->consume_each(read);
return 0;
}
} // namespace gmr1
} // namespace gr
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