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/* -*- c++ -*- */
/*
* Copyright 2005,2010,2012 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 "simple_squelch_cc_impl.h"
#include <gr_io_signature.h>
#include <cmath>
namespace gr {
namespace analog {
simple_squelch_cc::sptr
simple_squelch_cc::make(double threshold_db, double alpha)
{
return gnuradio::get_initial_sptr
(new simple_squelch_cc_impl(threshold_db, alpha));
}
simple_squelch_cc_impl::simple_squelch_cc_impl(double threshold_db, double alpha)
: gr_sync_block("simple_squelch_cc",
gr_make_io_signature(1, 1, sizeof(gr_complex)),
gr_make_io_signature(1, 1, sizeof(gr_complex))),
d_unmuted(false), d_iir(alpha)
{
set_threshold(threshold_db);
}
simple_squelch_cc_impl::~simple_squelch_cc_impl()
{
}
void
simple_squelch_cc_impl::set_threshold(double decibels)
{
// convert to absolute threshold (mag squared)
d_threshold = std::pow(10.0, decibels/10);
}
double
simple_squelch_cc_impl::threshold() const
{
return 10 * log10(d_threshold);
}
void
simple_squelch_cc_impl::set_alpha(double alpha)
{
d_iir.set_taps(alpha);
}
std::vector<float>
simple_squelch_cc_impl::squelch_range() const
{
std::vector<float> r(3);
r[0] = -50.0; // min FIXME
r[1] = +50.0; // max FIXME
r[2] = (r[1] - r[0]) / 100; // step size
return r;
}
int
simple_squelch_cc_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const gr_complex *in = (const gr_complex*)input_items[0];
gr_complex *out = (gr_complex*)output_items[0];
for(int i = 0; i < noutput_items; i++) {
double mag_sqrd = in[i].real()*in[i].real() + in[i].imag()*in[i].imag();
double f = d_iir.filter(mag_sqrd);
if(f >= d_threshold)
out[i] = in[i];
else
out[i] = 0;
}
d_unmuted = d_iir.prev_output() >= d_threshold;
return noutput_items;
}
} /* namespace analog */
} /* namespace gr */
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