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/* -*- c++ -*- */
/*
* Copyright 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 "cma_equalizer_cc_impl.h"
#include <gnuradio/io_signature.h>
namespace gr {
namespace digital {
using namespace filter::kernel;
cma_equalizer_cc::sptr
cma_equalizer_cc::make(int num_taps, float modulus, float mu, int sps)
{
return gnuradio::get_initial_sptr
(new cma_equalizer_cc_impl(num_taps, modulus, mu, sps));
}
cma_equalizer_cc_impl::cma_equalizer_cc_impl(int num_taps, float modulus,
float mu, int sps)
: sync_decimator("cma_equalizer_cc",
io_signature::make(1, 1, sizeof(gr_complex)),
io_signature::make(1, 1, sizeof(gr_complex)),
sps),
fir_filter_ccc(sps, std::vector<gr_complex>(num_taps, gr_complex(0,0))),
d_new_taps(num_taps, gr_complex(0,0)),
d_updated(false), d_error(gr_complex(0,0))
{
set_modulus(modulus);
set_gain(mu);
if(num_taps > 0)
d_new_taps[0] = 1.0;
fir_filter_ccc::set_taps(d_new_taps);
set_history(num_taps);
}
cma_equalizer_cc_impl::~cma_equalizer_cc_impl()
{
}
void
cma_equalizer_cc_impl::set_taps(const std::vector<gr_complex> &taps)
{
d_new_taps = taps;
d_updated = true;
}
std::vector<gr_complex>
cma_equalizer_cc_impl::taps() const
{
return d_taps;
}
gr_complex
cma_equalizer_cc_impl::error(const gr_complex &out)
{
gr_complex error = out*(norm(out) - d_modulus);
float re = gr::clip(error.real(), 1.0);
float im = gr::clip(error.imag(), 1.0);
return gr_complex(re, im);
}
void
cma_equalizer_cc_impl::update_tap(gr_complex &tap, const gr_complex &in)
{
// Hn+1 = Hn - mu*conj(Xn)*zn*(|zn|^2 - 1)
tap -= d_mu*conj(in)*d_error;
}
int
cma_equalizer_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];
if(d_updated) {
d_taps = d_new_taps;
set_history(d_taps.size());
d_updated = false;
return 0; // history requirements may have changed.
}
int j = 0;
size_t k, l = d_taps.size();
for(int i = 0; i < noutput_items; i++) {
out[i] = filter(&in[j]);
// Adjust taps
d_error = error(out[i]);
for(k = 0; k < l; k++) {
// Update tap locally from error.
update_tap(d_taps[k], in[j+k]);
// Update aligned taps in filter object.
fir_filter_ccc::update_tap(d_taps[k], k);
}
j += decimation();
}
return noutput_items;
}
} /* namespace digital */
} /* namespace gr */
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