portapack-mayhem/firmware/baseband/dsp_squelch.cpp

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2015-08-27 16:59:03 +00:00
/*
* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
*
* This file is part of PortaPack.
*
* 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 2, 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; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "dsp_squelch.hpp"
#include <cstdint>
#include <array>
bool FMSquelch::execute(buffer_s16_t audio) {
// TODO: No hard-coded array size.
std::array<int16_t, N> squelch_energy_buffer;
const buffer_s16_t squelch_energy {
squelch_energy_buffer.data(),
squelch_energy_buffer.size()
};
non_audio_hpf.execute(audio, squelch_energy);
uint64_t max_squared = 0;
for(const auto sample : squelch_energy_buffer) {
const uint64_t sample_squared = sample * sample;
if( sample_squared > max_squared ) {
max_squared = sample_squared;
}
}
return (max_squared < (threshold * threshold));
}