diff options
| author | Bogdan Diaconescu <b_diaconescu@yahoo.com> | 2015-09-05 16:35:12 -0700 |
|---|---|---|
| committer | Ron Economos <w6rz@comcast.net> | 2015-09-05 16:35:12 -0700 |
| commit | 0b05c304f420196874f2a13bb21420a7609eb778 (patch) | |
| tree | 0247726280e3967bae9853062f721125ab58dd7a /gr-dtv/lib/dvbt/dvbt_demod_reference_signals_impl.cc | |
| parent | 80d52551db67b2e80955eaadbbc63a54d4d4abbc (diff) | |
Add DVB-T receiver.
Diffstat (limited to 'gr-dtv/lib/dvbt/dvbt_demod_reference_signals_impl.cc')
| -rw-r--r-- | gr-dtv/lib/dvbt/dvbt_demod_reference_signals_impl.cc | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/gr-dtv/lib/dvbt/dvbt_demod_reference_signals_impl.cc b/gr-dtv/lib/dvbt/dvbt_demod_reference_signals_impl.cc new file mode 100644 index 0000000000..e9ee86436b --- /dev/null +++ b/gr-dtv/lib/dvbt/dvbt_demod_reference_signals_impl.cc @@ -0,0 +1,152 @@ +/* -*- c++ -*- */ +/* + * Copyright 2015 Free Software Foundation, Inc. + * + * 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 <gnuradio/io_signature.h> +#include "dvbt_demod_reference_signals_impl.h" + +namespace gr { + namespace dtv { + + dvbt_demod_reference_signals::sptr + dvbt_demod_reference_signals::make(int itemsize, int ninput, int noutput, \ + dvb_constellation_t constellation, dvbt_hierarchy_t hierarchy, \ + dvb_code_rate_t code_rate_HP, dvb_code_rate_t code_rate_LP, \ + dvb_guardinterval_t guard_interval, dvbt_transmission_mode_t transmission_mode, \ + int include_cell_id, int cell_id) + { + return gnuradio::get_initial_sptr + (new dvbt_demod_reference_signals_impl(itemsize, ninput, \ + noutput, constellation, hierarchy, code_rate_HP, code_rate_LP, \ + guard_interval, transmission_mode, include_cell_id, cell_id)); + } + + /* + * The private constructor + */ + dvbt_demod_reference_signals_impl::dvbt_demod_reference_signals_impl(int itemsize, int ninput, int noutput, \ + dvb_constellation_t constellation, dvbt_hierarchy_t hierarchy, dvb_code_rate_t code_rate_HP,\ + dvb_code_rate_t code_rate_LP, dvb_guardinterval_t guard_interval,\ + dvbt_transmission_mode_t transmission_mode, int include_cell_id, int cell_id) + : block("dvbt_demod_reference_signals", + io_signature::make(1, 1, itemsize * ninput), + io_signature::make(1, 1, itemsize * noutput)), + config(constellation, hierarchy, code_rate_HP, code_rate_LP, \ + guard_interval, transmission_mode, include_cell_id, cell_id), + d_pg(config), + d_init(0), + d_fi_start(0) + { + d_ninput = ninput; + d_noutput = noutput; + + // TODO - investigate why this is happening + if ((config.d_constellation == MOD_64QAM) && (config.d_transmission_mode == T8k)) + d_fi_start = 2; + else + d_fi_start = 3; + } + + /* + * Our virtual destructor. + */ + dvbt_demod_reference_signals_impl::~dvbt_demod_reference_signals_impl() + { + } + + void + dvbt_demod_reference_signals_impl::forecast (int noutput_items, gr_vector_int &ninput_items_required) + { + int ninputs = ninput_items_required.size(); + + for (int i = 0; i < ninputs; i++) + ninput_items_required[i] = 2 * noutput_items; + } + + int + dvbt_demod_reference_signals_impl::is_sync_start(int nitems) + { + std::vector<tag_t> tags; + const uint64_t nread = this->nitems_read(0); //number of items read on port 0 + this->get_tags_in_range(tags, 0, nread, nread + nitems, pmt::string_to_symbol("sync_start")); + + return tags.size() ? 1 : 0; + } + + int + dvbt_demod_reference_signals_impl::general_work (int noutput_items, + gr_vector_int &ninput_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]; + + int symbol_index, frame_index; + int to_out = 0; + + for (int i = 0; i < noutput_items; i++) { + to_out += d_pg.parse_input(&in[i * d_ninput], &out[i * d_noutput], &symbol_index, &frame_index); + } + + /* + * Wait for a sync_start tag from upstream that signals when to start. + * Allways consume until to a superframe start. + */ + if (is_sync_start(noutput_items)) { + d_init = 0; + } + + if (d_init == 0) { + // This is super-frame start + if (((symbol_index % 68) == 0) && ((frame_index % 4) == d_fi_start)) { + d_init = 1; + + const uint64_t offset = this->nitems_written(0); + pmt::pmt_t key = pmt::string_to_symbol("superframe_start"); + pmt::pmt_t value = pmt::from_long(0xaa); + this->add_item_tag(0, offset, key, value); + } + else { + consume_each(1); + return (0); + } + } + + // Send a tag for each OFDM symbol informing about + // symbol index. + const uint64_t offset = this->nitems_written(0); + pmt::pmt_t key = pmt::string_to_symbol("symbol_index"); + pmt::pmt_t value = pmt::from_long(symbol_index); + this->add_item_tag(0, offset, key, value); + + // Consume from input stream + consume_each (noutput_items); + + // Tell runtime system how many output items we produced. + return to_out; + } + + } /* namespace dtv */ +} /* namespace gr */ + |