gr-satnogs/lib/cw_encoder_impl.cc

149 lines
3.9 KiB
C++

/* -*- c++ -*- */
/*
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
*
* Copyright (C) 2017
* Libre Space Foundation <http://librespacefoundation.org/>
*
* This program 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 of the License, or
* (at your option) any later version.
*
* This program 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 program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gnuradio/io_signature.h>
#include <satnogs/log.h>
#include "cw_encoder_impl.h"
namespace gr {
namespace satnogs {
cw_encoder::sptr
cw_encoder::make(double samp_rate, double cw_freq, size_t wpm)
{
return gnuradio::get_initial_sptr
(new cw_encoder_impl(samp_rate, cw_freq, wpm));
}
/*
* The private constructor
*/
cw_encoder_impl::cw_encoder_impl(double samp_rate, double cw_freq,
size_t wpm)
: gr::sync_block("cw_encoder",
gr::io_signature::make(0, 0, 0),
gr::io_signature::make(1, 1, sizeof(gr_complex))),
d_samp_rate(samp_rate),
d_cw_freq(cw_freq),
d_wpm(wpm),
d_dot_samples((1.2 / wpm) / (1.0 / samp_rate)),
d_window_size(0),
d_windows_remaining(0),
d_cw_symbol(MORSE_L_SPACE),
d_nco()
{
message_port_register_in(pmt::mp("symbol"));
/*
* Try to split the CW pulses in smaller windows for dealing efficiently
* with the available buffer size
*/
size_t i = 10;
d_window_size = d_dot_samples / i;
while (d_window_size > 200) {
i += 10;
d_window_size = d_dot_samples / i;
}
/* NOTE: The dot duration should be a perfect multiple of the window */
while (d_dot_samples % d_window_size != 0) {
d_window_size++;
}
set_output_multiple(d_window_size);
d_nco.set_freq((2 * M_PI * cw_freq) / samp_rate);
}
/*
* Our virtual destructor.
*/
cw_encoder_impl::~cw_encoder_impl()
{
}
int
cw_encoder_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
size_t available;
size_t i;
gr_complex *out = (gr_complex *) output_items[0];
if (noutput_items < 0) {
return noutput_items;
}
if (d_windows_remaining == 0) {
pmt::pmt_t symbol = delete_head_nowait(pmt::mp("symbol"));
if (symbol.get() == nullptr) {
return 0;
}
d_cw_symbol = (morse_symbol_t) pmt::to_long(symbol);
/* Reset NCO so the amplitude starts from zero */
d_nco.set_freq((2 * M_PI * d_cw_freq) / d_samp_rate);
switch (d_cw_symbol) {
case MORSE_DOT:
case MORSE_INTRA_SPACE:
d_windows_remaining = d_dot_samples / d_window_size;
break;
case MORSE_DASH:
case MORSE_S_SPACE:
d_windows_remaining = (d_dot_samples / d_window_size) * 3;
break;
case MORSE_L_SPACE:
d_windows_remaining = (d_dot_samples / d_window_size) * 7;
break;
default:
LOG_WARN("Unrecognized CW symbol");
return 0;
}
}
for (i = 0; i < (size_t)noutput_items / d_window_size; i++) {
switch (d_cw_symbol) {
case MORSE_S_SPACE:
case MORSE_L_SPACE:
case MORSE_INTRA_SPACE:
memset(out + i * d_window_size, 0,
d_window_size * sizeof(gr_complex));
break;
case MORSE_DOT:
case MORSE_DASH:
d_nco.sincos(out + i * d_window_size, d_window_size, 1.0);
break;
}
d_windows_remaining--;
if (d_windows_remaining == 0) {
return (i + 1) * d_window_size;
}
}
return i * d_window_size;
}
} /* namespace satnogs */
} /* namespace gr */