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https://github.com/portapack-mayhem/mayhem-firmware.git
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31e8019642
* WIP Refactoring * WordExtractor building * Fix buffer sizes and squelch execute * Move impls to cpp file * Baud indicator * WIP new bit extractor * New approach for bit extraction. * Code fit and finish * Fix case on button * Cleanup * Adjust rate miss threshold * Fix count bits error calculation.
58 lines
1.9 KiB
C++
58 lines
1.9 KiB
C++
/*
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* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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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 2, or (at your option)
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* 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; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#include "dsp_squelch.hpp"
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#include <cstdint>
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#include <array>
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bool FMSquelch::execute(const buffer_f32_t& audio) {
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if (threshold_squared == 0.0f) {
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return true;
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}
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// TODO: alloca temp buffer, assert audio.count
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std::array<float, 32> squelch_energy_buffer;
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const buffer_f32_t squelch_energy{squelch_energy_buffer.data(), audio.count};
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non_audio_hpf.execute(audio, squelch_energy);
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// "Non-audio" implies "noise" here. Find the loudest noise sample.
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float non_audio_max_squared = 0;
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for (size_t i = 0; i < squelch_energy.count; ++i) {
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auto sample = squelch_energy.p[i];
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float sample_squared = sample * sample;
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if (sample_squared > non_audio_max_squared)
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non_audio_max_squared = sample_squared;
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}
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// Is the noise less than the threshold?
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return (non_audio_max_squared < threshold_squared);
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}
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void FMSquelch::set_threshold(const float new_value) {
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threshold_squared = new_value * new_value;
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}
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bool FMSquelch::enabled() const {
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return threshold_squared > 0.0;
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}
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