212 lines
5.1 KiB
C++
212 lines
5.1 KiB
C++
/* -*- c++ -*- */
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/*
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* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
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*
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* Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <gnuradio/io_signature.h>
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#include <satnogs/log.h>
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#include <satnogs/morse.h>
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#include "cw_to_symbol_impl.h"
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namespace gr
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{
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namespace satnogs
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{
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cw_to_symbol::sptr
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cw_to_symbol::make (double sampling_rate, float threshold, size_t wpm)
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{
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return gnuradio::get_initial_sptr (
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new cw_to_symbol_impl (sampling_rate, threshold, wpm));
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}
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/*
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* The private constructor
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*/
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cw_to_symbol_impl::cw_to_symbol_impl (double sampling_rate, float threshold,
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size_t wpm) :
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gr::sync_block ("cw_to_symbol",
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gr::io_signature::make (1, 1, sizeof(float)),
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gr::io_signature::make (0, 0, 0)),
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d_sampling_rate(sampling_rate),
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d_act_thrshld(threshold),
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d_confidence_level(0.90),
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d_dot_samples((1.2/wpm) / (1.0 / sampling_rate)),
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d_dash_samples(3 * d_dot_samples),
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d_short_pause_samples(3 * d_dot_samples),
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d_long_pause_samples(7 * d_dot_samples),
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d_state(IDLE),
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d_state_cnt(0),
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d_pause_cnt(0)
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{
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message_port_register_out(pmt::mp("out"));
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}
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/*
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* Our virtual destructor.
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*/
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cw_to_symbol_impl::~cw_to_symbol_impl ()
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{
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}
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inline void
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cw_to_symbol_impl::set_idle ()
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{
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d_state = IDLE;
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d_state_cnt = 0;
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d_pause_cnt = 0;
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}
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inline void
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cw_to_symbol_impl::set_short_on ()
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{
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d_state = SHORT_ON_PERIOD;
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d_state_cnt = 1;
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}
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inline void
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cw_to_symbol_impl::set_long_on ()
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{
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d_state = LONG_ON_PERIOD;
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d_pause_cnt = 0;
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}
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inline void
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cw_to_symbol_impl::set_short_off (size_t borrow_cnt)
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{
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d_state = SHORT_OFF_PERIOD;
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d_state_cnt = 0;
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d_pause_cnt += borrow_cnt;
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/* Due to time-slots borrowing we may be already at the Long pause */
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if(d_pause_cnt > d_short_pause_samples) {
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d_state = LONG_OFF_PERIOD;
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}
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}
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inline void
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cw_to_symbol_impl::set_long_off ()
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{
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d_state = LONG_OFF_PERIOD;
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}
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int
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cw_to_symbol_impl::work (int noutput_items,
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gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items)
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{
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int i;
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float conf_lvl;
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const float *in = (const float *) input_items[0];
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for(i = 0; i < noutput_items; i++) {
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switch(d_state){
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case IDLE:
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if(in[i] > d_act_thrshld) {
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set_short_on();
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}
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// TODO Avoid unnecessary pause messages
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break;
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case SHORT_ON_PERIOD:
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if( in[i] > d_act_thrshld ) {
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d_state_cnt++;
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if(d_state_cnt > d_dot_samples){
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set_long_on();
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}
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}
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else{
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/*
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* Before going to short pause, check the confidence level.
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* Perhaps a short symbol should be produced.
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*
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* Otherwise, it was a false alarm. So the time-slots counted
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* so far should be assigned as pause time-slots.
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*/
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conf_lvl = ((float) d_state_cnt) / d_dot_samples;
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if(conf_lvl > d_confidence_level){
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message_port_pub(pmt::mp("out"), pmt::from_long(MORSE_DOT));
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set_short_off(0);
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}
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else{
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set_short_off(d_state_cnt);
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}
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}
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break;
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case LONG_ON_PERIOD:
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if( in[i] > d_act_thrshld ) {
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d_state_cnt++;
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}
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else{
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/*
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* In this case the FSM should continue at the SHORT_OFF state.
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* Before this depending the confidence for a long pulse, produce
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* a short or long pulse message
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*/
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conf_lvl = ((float) d_state_cnt) / d_dash_samples;
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if(conf_lvl > d_confidence_level){
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message_port_pub(pmt::mp("out"), pmt::from_long(MORSE_DASH));
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}
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else{
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message_port_pub(pmt::mp("out"), pmt::from_long(MORSE_DOT));
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}
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set_short_off(0);
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}
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break;
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case SHORT_OFF_PERIOD:
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if(in[i] > d_act_thrshld) {
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set_short_on();
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}
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else {
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d_pause_cnt++;
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if(d_pause_cnt > d_short_pause_samples) {
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set_long_off();
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}
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}
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break;
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case LONG_OFF_PERIOD:
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if(in[i] > d_act_thrshld) {
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set_short_on();
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}
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else {
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d_pause_cnt++;
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if(d_pause_cnt > d_long_pause_samples) {
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message_port_pub(pmt::mp("out"), pmt::from_long(MORSE_L_SPACE));
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set_idle();
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}
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}
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break;
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default:
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LOG_ERROR("Invalid State.");
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d_state = IDLE;
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}
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}
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return noutput_items;
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}
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} /* namespace satnogs */
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} /* namespace gr */
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