HackRF-Treasure-Chest/Software/portapack-mayhem/firmware/baseband/dsp_squelch.cpp

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2022-09-22 18:26:57 +02:00
/*
* 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(const buffer_f32_t& audio) {
if( threshold_squared == 0.0f ) {
return true;
}
// TODO: No hard-coded array size.
std::array<float, N> squelch_energy_buffer;
const buffer_f32_t squelch_energy {
squelch_energy_buffer.data(),
squelch_energy_buffer.size()
};
non_audio_hpf.execute(audio, squelch_energy);
float non_audio_max_squared = 0;
for(const auto sample : squelch_energy_buffer) {
const float sample_squared = sample * sample;
if( sample_squared > non_audio_max_squared ) {
non_audio_max_squared = sample_squared;
}
}
return (non_audio_max_squared < threshold_squared);
}
void FMSquelch::set_threshold(const float new_value) {
threshold_squared = new_value * new_value;
}