mirror of
https://github.com/eried/portapack-mayhem.git
synced 2024-12-25 15:29:37 -05:00
120 lines
3.8 KiB
C++
120 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_wfm_audio.hpp"
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#include <cstdint>
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void WidebandFMAudio::execute(const buffer_c8_t& buffer) {
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if( !configured ) {
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return;
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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 decimator_out = decim_1_out;
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auto channel = decimator_out;
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// TODO: Feed channel_stats post-decimation data?
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feed_channel_stats(channel);
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spectrum_samples += channel.count;
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if( spectrum_samples >= spectrum_interval_samples ) {
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spectrum_samples -= spectrum_interval_samples;
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channel_spectrum.feed(channel, channel_filter_pass_f, channel_filter_stop_f);
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}
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/* 384kHz complex<int16_t>[256]
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* -> FM demodulation
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* -> 384kHz int16_t[256] */
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/* TODO: To improve adjacent channel rejection, implement complex channel filter:
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* pass < +/- 100kHz, stop > +/- 200kHz
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*/
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auto audio_oversampled = demod.execute(decimator_out, work_audio_buffer);
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/* 384kHz int16_t[256]
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* -> 4th order CIC decimation by 2, gain of 1
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* -> 192kHz int16_t[128] */
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auto audio_4fs = audio_dec_1.execute(audio_oversampled, work_audio_buffer);
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/* 192kHz int16_t[128]
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* -> 4th order CIC decimation by 2, gain of 1
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* -> 96kHz int16_t[64] */
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auto audio_2fs = audio_dec_2.execute(audio_4fs, work_audio_buffer);
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/* 96kHz int16_t[64]
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* -> FIR filter, <15kHz (0.156fs) pass, >19kHz (0.198fs) stop, gain of 1
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* -> 48kHz int16_t[32] */
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auto audio = audio_filter.execute(audio_2fs, work_audio_buffer);
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/* -> 48kHz int16_t[32] */
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audio_hpf.execute_in_place(audio);
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audio_deemph.execute_in_place(audio);
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fill_audio_buffer(audio);
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}
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void WidebandFMAudio::on_message(const Message* const message) {
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switch(message->id) {
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case Message::ID::UpdateSpectrum:
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channel_spectrum.update();
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break;
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case Message::ID::WFMConfigure:
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configure(*reinterpret_cast<const WFMConfigureMessage*>(message));
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break;
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default:
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break;
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}
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}
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void WidebandFMAudio::configure(const WFMConfigureMessage& message) {
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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 = 4;
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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 = 2;
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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 demod_input_fs = decim_1_output_fs;
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constexpr auto spectrum_rate_hz = 50.0f;
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spectrum_interval_samples = decim_1_output_fs / spectrum_rate_hz;
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spectrum_samples = 0;
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decim_0.configure(message.decim_0_filter.taps, 33554432);
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decim_1.configure(message.decim_1_filter.taps, 131072);
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channel_filter_pass_f = message.decim_1_filter.pass_frequency_normalized * decim_1_input_fs;
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channel_filter_stop_f = message.decim_1_filter.stop_frequency_normalized * decim_1_input_fs;
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demod.configure(demod_input_fs, message.deviation);
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audio_filter.configure(message.audio_filter.taps);
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channel_spectrum.set_decimation_factor(1);
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configured = true;
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}
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