diff options
Diffstat (limited to 'gr-digital/lib/lms_dd_equalizer_cc_impl.cc')
| -rw-r--r-- | gr-digital/lib/lms_dd_equalizer_cc_impl.cc | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/gr-digital/lib/lms_dd_equalizer_cc_impl.cc b/gr-digital/lib/lms_dd_equalizer_cc_impl.cc new file mode 100644 index 0000000000..15008ca8e7 --- /dev/null +++ b/gr-digital/lib/lms_dd_equalizer_cc_impl.cc @@ -0,0 +1,137 @@ +/* -*- 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 "lms_dd_equalizer_cc_impl.h" +#include <gr_io_signature.h> +#include <gr_misc.h> +#include <volk/volk.h> + +namespace gr { + namespace digital { + + using namespace filter::kernel; + + lms_dd_equalizer_cc::sptr + lms_dd_equalizer_cc::make(int num_taps, float mu, int sps, + constellation_sptr cnst) + { + return gnuradio::get_initial_sptr + (new lms_dd_equalizer_cc_impl(num_taps, mu, sps, cnst)); + } + + lms_dd_equalizer_cc_impl::lms_dd_equalizer_cc_impl(int num_taps, float mu, + int sps, + constellation_sptr cnst) + : gr_sync_decimator("lms_dd_equalizer_cc", + gr_make_io_signature(1, 1, sizeof(gr_complex)), + gr_make_io_signature(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_cnst(cnst) + { + set_gain(mu); + if(num_taps > 0) + d_new_taps[0] = 1.0; + fir_filter_ccc::set_taps(d_new_taps); + + const int alignment_multiple = + volk_get_alignment() / sizeof(gr_complex); + set_alignment(std::max(1,alignment_multiple)); + + set_history(num_taps); + } + + lms_dd_equalizer_cc_impl::~lms_dd_equalizer_cc_impl() + { + } + + void + lms_dd_equalizer_cc_impl::set_taps(const std::vector<gr_complex> &taps) + { + d_new_taps = taps; + d_updated = true; + } + + std::vector<gr_complex> + lms_dd_equalizer_cc_impl::taps() const + { + return d_taps; + } + + gr_complex + lms_dd_equalizer_cc_impl::error(const gr_complex &out) + { + gr_complex decision, error; + d_cnst->map_to_points(d_cnst->decision_maker(&out), &decision); + error = decision - out; + return error; + } + + void + lms_dd_equalizer_cc_impl::update_tap(gr_complex &tap, const gr_complex &in) + { + tap += d_mu*conj(in)*d_error; + } + + int + lms_dd_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 */ |