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/* -*- c++ -*- */
/*
* Copyright 2011 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 <digital_lms_dd_equalizer_cc.h>
#include <gr_io_signature.h>
#include <gr_misc.h>
#include <iostream>
digital_lms_dd_equalizer_cc_sptr
digital_make_lms_dd_equalizer_cc (float mu, int ntaps,
digital_constellation_sptr cnst)
{
return gnuradio::get_initial_sptr(new digital_lms_dd_equalizer_cc (mu, ntaps, cnst));
}
digital_lms_dd_equalizer_cc::digital_lms_dd_equalizer_cc (float mu, int ntaps,
digital_constellation_sptr cnst)
: gr_sync_block ("lms_dd_equalizer_cc",
gr_make_io_signature (1, 1, sizeof (gr_complex)),
gr_make_io_signature (1, 1, sizeof (gr_complex))),
d_taps(ntaps), d_cnst(cnst)
{
set_mu(mu);
gr_zero_vector(d_taps);
d_taps [d_taps.size()/2] = 1;
set_history(ntaps+1);
}
float
digital_lms_dd_equalizer_cc::get_mu()
{
return d_mu;
}
void
digital_lms_dd_equalizer_cc::set_mu(float mu)
{
if(mu < 0.0f || mu > 1.0f) {
throw std::out_of_range("digital_lms_dd_equalizer::set_mu: Gain value must in [0, 1]");
}
else {
d_mu = mu;
}
}
int
digital_lms_dd_equalizer_cc::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];
gr_complex acc, decision, error;
for(int i = 0; i < noutput_items; i++) {
acc = 0;
// Compute output
for (size_t j=0; j < d_taps.size(); j++)
acc += in[i+j] * conj(d_taps[j]);
d_cnst->map_to_points(d_cnst->decision_maker(&acc), &decision);
error = decision - acc;
// Update taps
for (size_t j=0; j < d_taps.size(); j++)
d_taps[j] += d_mu * conj(error) * in[i+j];
out[i] = acc;
}
return noutput_items;
}
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