mayhem-firmware/firmware/baseband/proc_wideband_spectrum.cpp

70 lines
1.9 KiB
C++

/*
* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
*
* This file is part of PortaPack.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "proc_wideband_spectrum.hpp"
#include "event_m4.hpp"
#include "i2s.hpp"
using namespace lpc43xx;
#include "dsp_fft.hpp"
#include <cstdint>
#include <cstddef>
#include <array>
void WidebandSpectrum::execute(buffer_c8_t buffer) {
// 2048 complex8_t samples per buffer.
// 102.4us per buffer. 20480 instruction cycles per buffer.
static int phase = 0;
if( phase == 0 ) {
std::fill(spectrum.begin(), spectrum.end(), 0);
}
if( (phase & 7) == 0 ) {
// TODO: Removed window-presum windowing, due to lack of available code RAM.
// TODO: Apply window to improve spectrum bin sidelobes.
for(size_t i=0; i<channel_spectrum.size(); i++) {
spectrum[i] += std::complex<float> { buffer.p[i].real(), buffer.p[i].imag() };
}
}
if( phase == 23 ) {
if( channel_spectrum_request_update == false ) {
fft_swap(spectrum, channel_spectrum);
channel_spectrum_sampling_rate = buffer.sampling_rate;
channel_filter_pass_frequency = 0;
channel_filter_stop_frequency = 0;
channel_spectrum_request_update = true;
events_flag(EVT_MASK_SPECTRUM);
phase = 0;
}
} else {
phase++;
}
i2s::i2s0::tx_mute();
}