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https://github.com/portapack-mayhem/mayhem-firmware.git
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7710b2d1fa
Separate channel spectrum config from spectrum data. This will permit sending config info only when necessary. Use type information of ChannelSpectrum to statically define number of FFT bins elsewhere. TODO: Posting configuration message way too often. Fixing that is the next step.
102 lines
3.1 KiB
C++
102 lines
3.1 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 "spectrum_collector.hpp"
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#include "dsp_fft.hpp"
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#include "utility.hpp"
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#include "event_m4.hpp"
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#include "portapack_shared_memory.hpp"
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#include <algorithm>
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void SpectrumCollector::set_decimation_factor(
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const size_t decimation_factor
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) {
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channel_spectrum_decimator.set_factor(decimation_factor);
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}
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/* TODO: Refactor to register task with idle thread?
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* It's sad that the idle thread has to call all the way back here just to
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* perform the deferred task on the buffer of data we prepared.
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*/
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void SpectrumCollector::feed(
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const buffer_c16_t& channel,
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const uint32_t filter_pass_frequency,
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const uint32_t filter_stop_frequency
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) {
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// Called from baseband processing thread.
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channel_filter_pass_frequency = filter_pass_frequency;
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channel_filter_stop_frequency = filter_stop_frequency;
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post_configuration_message();
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channel_spectrum_decimator.feed(
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channel,
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[this](const buffer_c16_t& data) {
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this->post_message(data);
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}
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);
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}
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void SpectrumCollector::post_message(const buffer_c16_t& data) {
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// Called from baseband processing thread.
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if( !channel_spectrum_request_update ) {
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fft_swap(data, channel_spectrum);
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channel_spectrum_sampling_rate = data.sampling_rate;
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channel_spectrum_request_update = true;
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events_flag(EVT_MASK_SPECTRUM);
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}
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}
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void SpectrumCollector::post_configuration_message() {
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ChannelSpectrumConfigMessage message {
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channel_spectrum_sampling_rate,
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channel_filter_pass_frequency,
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channel_filter_stop_frequency,
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&fifo
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};
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shared_memory.application_queue.push(message);
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}
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void SpectrumCollector::update() {
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// Called from idle thread (after EVT_MASK_SPECTRUM is flagged)
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if( channel_spectrum_request_update ) {
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/* Decimated buffer is full. Compute spectrum. */
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channel_spectrum_request_update = false;
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fft_c_preswapped(channel_spectrum);
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ChannelSpectrum spectrum;
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for(size_t i=0; i<spectrum.db.size(); i++) {
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// Three point Hamming window.
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const auto corrected_sample = channel_spectrum[i] * 0.54f
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+ (channel_spectrum[(i-1) & 0xff] + channel_spectrum[(i+1) & 0xff]) * -0.23f;
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const auto mag2 = magnitude_squared(corrected_sample);
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const float db = complex16_mag_squared_to_dbv_norm(mag2);
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constexpr float mag_scale = 5.0f;
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const unsigned int v = (db * mag_scale) + 255.0f;
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spectrum.db[i] = std::max(0U, std::min(255U, v));
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}
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fifo.in(spectrum);
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}
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}
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