mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
synced 2024-12-15 20:50:28 +00:00
98 lines
3.8 KiB
C++
98 lines
3.8 KiB
C++
/*
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* Copyright (C) 2014 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 "proc_am_audio.hpp"
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// DSB AM 6K00A3E emission type ///////////////////////////////////////////
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// IFIR image-reject filter: fs=3072000, pass=3000, stop=339000, decim=8, fout=384000
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static constexpr std::array<int16_t, 24> taps_6k0_decim_0 { {
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39, 104, 224, 412, 674, 1008, 1400, 1821,
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2234, 2594, 2863, 3006, 3006, 2863, 2594, 2234,
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1821, 1400, 1008, 674, 412, 224, 104, 39,
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} };
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// IFIR prototype filter: fs=384000, pass=3000, stop=45000, decim=8, fout=48000
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static constexpr std::array<int16_t, 32> taps_6k0_decim_1 { {
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-26, -63, -123, -195, -263, -295, -253, -99,
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199, 651, 1242, 1927, 2633, 3273, 3760, 4023,
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4023, 3760, 3273, 2633, 1927, 1242, 651, 199,
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-99, -253, -295, -263, -195, -123, -63, -26,
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} };
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// Channel filter: fs=48000, pass=3000, stop=6700, decim=1, fout=48000
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static constexpr std::array<int16_t, 32> taps_6k0_channel { {
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95, 178, 247, 208, -21, -474, -1080, -1640,
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-1857, -1411, -83, 2134, 4978, 7946, 10413, 11815,
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11815, 10413, 7946, 4978, 2134, -83, -1411, -1857,
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-1640, -1080, -474, -21, 208, 247, 178, 95,
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} };
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NarrowbandAMAudio::NarrowbandAMAudio() {
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constexpr size_t baseband_fs = 3072000;
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constexpr size_t decim_0_input_fs = baseband_fs;
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constexpr size_t decim_0_decimation_factor = 8;
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constexpr size_t decim_0_output_fs = decim_0_input_fs / decim_0_decimation_factor;
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constexpr size_t decim_1_input_fs = decim_0_output_fs;
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constexpr size_t decim_1_decimation_factor = 8;
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constexpr size_t decim_1_output_fs = decim_1_input_fs / decim_1_decimation_factor;
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constexpr size_t channel_filter_input_fs = decim_1_output_fs;
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constexpr size_t channel_filter_decimation_factor = 1;
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constexpr size_t channel_filter_output_fs = channel_filter_input_fs / channel_filter_decimation_factor;
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decim_0.configure(taps_6k0_decim_0, 33554432);
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decim_1.configure(taps_6k0_decim_1, 131072);
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channel_filter.configure(taps_6k0_channel, 1);
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channel_filter_pass_f = 3000;
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channel_filter_stop_f = 6700;
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channel_spectrum.set_decimation_factor(std::floor((channel_filter_output_fs / 2) / ((channel_filter_pass_f + channel_filter_stop_f) / 2)));
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}
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void NarrowbandAMAudio::execute(const buffer_c8_t& buffer) {
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const buffer_c16_t dst_buffer {
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dst.data(),
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dst.size()
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};
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const auto decim_0_out = decim_0.execute(buffer, dst_buffer);
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const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
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const auto channel_out = channel_filter.execute(decim_1_out, dst_buffer);
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// TODO: Feed channel_stats post-decimation data?
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feed_channel_stats(channel_out);
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channel_spectrum.feed(channel_out, channel_filter_pass_f, channel_filter_stop_f);
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const buffer_s16_t work_audio_buffer {
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(int16_t*)dst.data(),
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sizeof(*dst.data()) * dst.size()
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};
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auto audio = demod.execute(channel_out, work_audio_buffer);
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audio_hpf.execute_in_place(audio);
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fill_audio_buffer(audio);
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}
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