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https://github.com/portapack-mayhem/mayhem-firmware.git
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7de80edcd3
They will likely be shared with multiple decimators/demodulators. Also added normalized filter pass/stop values to each set of taps.
118 lines
4.3 KiB
C++
118 lines
4.3 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_nfm_audio.hpp"
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#include <cstdint>
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#include <cstddef>
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NarrowbandFMAudio::NarrowbandFMAudio() {
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set_mode(Mode::Deviation2K5Narrow);
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}
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void NarrowbandFMAudio::set_mode(const Mode mode) {
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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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constexpr size_t demod_input_fs = channel_filter_output_fs;
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switch(mode) {
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default:
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case Mode::Deviation5K:
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decim_0.configure(taps_16k0_decim_0.taps, 33554432);
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decim_1.configure(taps_16k0_decim_1.taps, 131072);
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channel_filter.configure(taps_16k0_channel.taps, channel_filter_decimation_factor);
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demod.configure(demod_input_fs, 5000);
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channel_filter_pass_f = taps_16k0_channel.pass_frequency_normalized * channel_filter_input_fs;
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channel_filter_stop_f = taps_16k0_channel.stop_frequency_normalized * channel_filter_input_fs;
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break;
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case Mode::Deviation2K5Wide:
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decim_0.configure(taps_11k0_decim_0.taps, 33554432);
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decim_1.configure(taps_11k0_decim_1.taps, 131072);
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channel_filter.configure(taps_11k0_channel.taps, channel_filter_decimation_factor);
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demod.configure(demod_input_fs, 2500);
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channel_filter_pass_f = taps_11k0_channel.pass_frequency_normalized * channel_filter_input_fs;
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channel_filter_stop_f = taps_11k0_channel.stop_frequency_normalized * channel_filter_input_fs;
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break;
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case Mode::Deviation2K5Narrow:
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decim_0.configure(taps_4k25_decim_0.taps, 33554432);
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decim_1.configure(taps_4k25_decim_1.taps, 131072);
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channel_filter.configure(taps_4k25_channel.taps, channel_filter_decimation_factor);
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demod.configure(demod_input_fs, 2500);
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channel_filter_pass_f = taps_4k25_channel.pass_frequency_normalized * channel_filter_input_fs;
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channel_filter_stop_f = taps_4k25_channel.stop_frequency_normalized * channel_filter_input_fs;
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break;
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}
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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 NarrowbandFMAudio::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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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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static uint64_t audio_present_history = 0;
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const auto audio_present_now = squelch.execute(audio);
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audio_present_history = (audio_present_history << 1) | (audio_present_now ? 1 : 0);
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const bool audio_present = (audio_present_history != 0);
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audio_hpf.execute_in_place(audio);
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audio_deemph.execute_in_place(audio);
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if( !audio_present ) {
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// Zero audio buffer.
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for(size_t i=0; i<audio.count; i++) {
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audio.p[i] = 0;
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}
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}
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fill_audio_buffer(audio);
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}
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