373 lines
10 KiB
C++
373 lines
10 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) 2016-2018
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* 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 "cw_to_symbol_impl.h"
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#include <limits>
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#include <gnuradio/io_signature.h>
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#include <satnogs/log.h>
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#include <satnogs/utils.h>
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#include <boost/version.hpp>
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#if BOOST_VERSION >= 106500
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#include <boost/integer/common_factor.hpp>
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#else
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#include <boost/math/common_factor.hpp>
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#endif
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#include <volk/volk.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, float conf_level,
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size_t wpm, size_t hysteresis)
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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, conf_level, wpm,
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hysteresis));
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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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float conf_level, size_t wpm,
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size_t hysteresis) :
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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 (conf_level),
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d_dot_samples ((1.2 / wpm) * sampling_rate),
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d_window_size (0),
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d_window_cnt (0),
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d_idle_cnt (0),
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d_dot_windows_num (0),
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d_dec_state (NO_SYNC),
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d_prev_space_symbol (true)
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{
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if (wpm < MIN_WPM) {
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throw std::invalid_argument ("Decoder can not handle such low WPM setting");
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}
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if (wpm > MAX_WPM) {
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throw std::invalid_argument (
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"Decoder can not handle such high WPM setting");
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}
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if (conf_level > 1.0 || conf_level < 0.5) {
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throw std::invalid_argument (
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"Confidence level should be in the range [0.5, 1.0]");
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}
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if(hysteresis > d_dot_samples / 4) {
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throw std::invalid_argument ("Too large hysteresis value");
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}
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message_port_register_in (pmt::mp ("act_threshold"));
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message_port_register_out (pmt::mp ("out"));
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/* Register the message handlers */
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set_msg_handler (
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pmt::mp ("act_threshold"),
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boost::bind (&cw_to_symbol_impl::set_act_threshold_msg_handler, this,
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_1));
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/*
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* Reconsider the dot oulse duration based on the confidence level
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* and hysteresis
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*/
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d_dot_samples = d_dot_samples - 2 * (hysteresis * conf_level);
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/*
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* Try to split the CW pulses in smaller windows for detecting faster
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* a false alarm. As we use the window size for setting the history
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* it should have a reasonably size.
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*/
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size_t i = 1;
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d_window_size = d_dot_samples / i;
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while (d_window_size > 64) {
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i++;
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d_window_size = d_dot_samples / i;
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}
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/* NOTE: The dot duration should be a perfect multiple of the window */
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while (d_dot_samples % d_window_size != 0) {
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d_window_size++;
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}
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LOG_DEBUG("Dot symbol samples: %lu", d_dot_samples);
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LOG_DEBUG("Window size: %lu", d_window_size);
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/* Set the duration of each symbol in multiples of the window size */
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d_dot_windows_num = d_dot_samples / d_window_size;
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d_dash_windows_num = 3 * d_dot_windows_num;
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d_short_pause_windows_num = d_dash_windows_num;
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d_long_pause_windows_num = 7 * d_dot_windows_num;
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const int alignment_multiple = volk_get_alignment ()
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/ (d_window_size * sizeof(float));
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set_alignment (std::max (1, alignment_multiple));
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d_const_val = (float *) volk_malloc (d_window_size * sizeof(float),
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volk_get_alignment ());
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d_tmp = (float *) volk_malloc (d_window_size * sizeof(float),
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volk_get_alignment ());
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d_out = (int32_t *) volk_malloc (d_window_size * sizeof(int32_t),
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volk_get_alignment ());
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if (!d_const_val || !d_tmp || !d_out) {
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throw std::runtime_error ("cw_to_symbol: Could not allocate memory");
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}
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for (i = 0; i < d_window_size; i++) {
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d_const_val[i] = threshold;
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}
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set_history (d_window_size);
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}
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inline void
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cw_to_symbol_impl::send_symbol_msg (morse_symbol_t s)
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{
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if (s == MORSE_S_SPACE || s == MORSE_L_SPACE) {
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d_prev_space_symbol = true;
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}
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else {
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d_prev_space_symbol = false;
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}
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message_port_pub (pmt::mp ("out"), pmt::from_long (s));
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}
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inline bool
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cw_to_symbol_impl::check_conf_level (size_t cnt, size_t target)
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{
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return ((float) cnt > target * d_confidence_level);
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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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volk_free (d_const_val);
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volk_free (d_tmp);
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volk_free (d_out);
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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_dec_state = NO_SYNC;
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d_window_cnt = 0;
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d_idle_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_dec_state = SEARCH_DOT;
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d_window_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_dec_state = SEARCH_DASH;
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}
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inline void
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cw_to_symbol_impl::set_search_space ()
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{
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d_dec_state = SEARCH_SPACE;
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d_window_cnt = 1;
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}
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void
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cw_to_symbol_impl::set_act_threshold_msg_handler (pmt::pmt_t msg)
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{
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if (pmt::is_pair (msg)) {
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set_act_threshold (pmt::to_double (pmt::cdr (msg)));
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}
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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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bool triggered;
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size_t i;
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const float *in_old = (const float *) input_items[0];
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const float *in = in_old + history () - 1;
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if (noutput_items < 0) {
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return noutput_items;
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}
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/* During idle state search for a possible trigger */
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if (d_dec_state == NO_SYNC) {
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for (i = 0; i < (size_t) noutput_items; i++) {
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/*
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* Clamp the input so the window mean is not affected by strong spikes
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* Good luck understanding this black magic shit!
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*/
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triggered = is_triggered (in_old + i, d_window_size);
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if (triggered) {
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LOG_DEBUG("Triggered!");
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set_short_on ();
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return i + 1;
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}
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}
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d_idle_cnt += noutput_items / d_window_size;
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if(d_idle_cnt > 10 * d_long_pause_windows_num) {
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send_symbol_msg (MORSE_END_MSG_SPACE);
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d_idle_cnt = 0;
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}
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return noutput_items;
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}
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/* From now one, we handle the input in multiples of a window */
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for (i = 0; i < (size_t) noutput_items / d_window_size; i++) {
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triggered = is_triggered (in + i * d_window_size, d_window_size);
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switch (d_dec_state)
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{
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case SEARCH_DOT:
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if (triggered) {
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d_window_cnt++;
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if (d_window_cnt > d_dot_windows_num) {
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set_long_on ();
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LOG_DEBUG("Going to search for long sequence");
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}
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}
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else {
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if (check_conf_level (d_window_cnt, d_dot_windows_num)) {
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LOG_DEBUG("DOT");
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send_symbol_msg (MORSE_DOT);
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}
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LOG_DEBUG("Going to search for space: win cnt %lu", d_window_cnt);
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set_search_space ();
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}
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break;
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case SEARCH_DASH:
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if (triggered) {
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d_window_cnt++;
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}
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else {
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if (check_conf_level (d_window_cnt, d_dash_windows_num)) {
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LOG_DEBUG("DASH");
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send_symbol_msg (MORSE_DASH);
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}
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else {
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LOG_DEBUG("DOT");
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send_symbol_msg (MORSE_DOT);
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}
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set_search_space ();
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LOG_DEBUG("Going to search for space");
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}
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break;
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case SEARCH_SPACE:
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if (triggered) {
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if (check_conf_level (d_window_cnt, d_long_pause_windows_num)) {
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LOG_DEBUG("LONG SPACE");
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send_symbol_msg (MORSE_L_SPACE);
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}
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else if (check_conf_level (d_window_cnt, d_short_pause_windows_num)) {
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LOG_DEBUG("SHORT SPACE");
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send_symbol_msg (MORSE_S_SPACE);
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}
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set_short_on ();
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LOG_DEBUG("Going to search for dot");
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}
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else {
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d_window_cnt++;
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if (d_window_cnt > d_long_pause_windows_num) {
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LOG_DEBUG("LONG SPACE");
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send_symbol_msg (MORSE_L_SPACE);
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set_idle ();
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LOG_DEBUG("Going to idle");
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return (i + 1) * d_window_size;
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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 decoder state");
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}
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}
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return i * d_window_size;
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}
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/**
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* Sets a new activation threshold.
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* @param thrhld the new threshold.
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*/
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void
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cw_to_symbol_impl::set_act_threshold (float thrhld)
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{
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d_act_thrshld = thrhld;
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}
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/**
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* Clamps the input and performs at the same time binary slicing.
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* With this way, a decision based on moving average is not affected
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* by strong peaks.
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* @param out the output buffer with the binary sliced output
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* @param in the input signal
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* @param len number of samples to process
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*/
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inline void
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cw_to_symbol_impl::clamp_input (int32_t* out, const float* in, size_t len)
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{
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volk_32f_x2_subtract_32f (d_tmp, in, d_const_val, len);
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volk_32f_binary_slicer_32i (d_out, d_tmp, len);
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}
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static inline int32_t
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hadd (const int32_t* in, size_t len)
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{
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size_t i;
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int32_t cnt = 0;
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for (i = 0; i < len; i++) {
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cnt += in[i];
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}
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return cnt;
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}
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inline bool
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cw_to_symbol_impl::is_triggered (const float* in, size_t len)
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{
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int32_t cnt;
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clamp_input (d_out, in, len);
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cnt = hadd (d_out, len);
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return (cnt >= (int32_t) (d_window_size * d_confidence_level)) ? true : false;
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}
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} /* namespace satnogs */
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} /* namespace gr */
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