portapack-mayhem/firmware/baseband/proc_subghzd.cpp

94 lines
3.8 KiB
C++

/*
* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2016 Furrtek
*
* 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_subghzd.hpp"
#include "portapack_shared_memory.hpp"
#include "event_m4.hpp"
void SubGhzDProcessor::execute(const buffer_c8_t& buffer) {
if (!configured) return;
// SR = 4Mhz , and we are decimating by /8 in total , decim1_out clock 4Mhz /8= 500khz samples/sec.
// buffer has 2048 complex i8 I,Q signed samples
// decim0 out: 2048/4 = 512 complex i16 I,Q signed samples
// decim1 out: 512/2 = 256 complex i16 I,Q signed samples
// Regarding Filters, we are re-using existing FIR filters, @4Mhz, FIR decim1 ilter, BW =+-220Khz (at -3dB's). BW = 440kHZ.
const auto decim_0_out = decim_0.execute(buffer, dst_buffer); // Input:2048 complex/4 (decim factor) = 512_output complex (1024 I/Q samples)
const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer); // Input:512 complex/2 (decim factor) = 256_output complex ( 512 I/Q samples)
for (size_t i = 0; i < decim_1_out.count; i++) {
int16_t re = decim_1_out.p[i].real();
int16_t im = decim_1_out.p[i].imag();
uint32_t mag = ((uint32_t)re * (uint32_t)re) + ((uint32_t)im * (uint32_t)im);
mag = (mag >> 12); // Decim samples are calculated with saturated gain . (we could also reduce that sat. param at configure time)
bool meashl = (mag > threshold);
tm += mag;
if (meashl == currentHiLow && currentDuration < 30'000'000) // allow pass 'end' signal
{
currentDuration += nsPerDecSamp;
} else { // called on change, so send the last duration and dir.
if (protoList) protoList->feed(currentHiLow, currentDuration / 1000);
currentDuration = nsPerDecSamp;
currentHiLow = meashl;
}
}
cnt += decim_1_out.count; // TODO , check if it is necessary that xdecim factor.
if (cnt > 90'000) {
threshold = (tm / cnt) / 2;
cnt = 0;
tm = 0;
if (threshold < 50) threshold = 50;
if (threshold > 1700) threshold = 1700;
}
}
void SubGhzDProcessor::on_message(const Message* const message) {
if (message->id == Message::ID::SubGhzFPRxConfigure)
configure(*reinterpret_cast<const SubGhzFPRxConfigureMessage*>(message));
}
void SubGhzDProcessor::configure(const SubGhzFPRxConfigureMessage& message) {
// constexpr size_t decim_0_output_fs = baseband_fs / decim_0.decimation_factor; //unused
// constexpr size_t decim_1_output_fs = decim_0_output_fs / decim_1.decimation_factor; //unused
modulation = message.modulation; // TODO: add support for FM (currently AM only)
baseband_fs = message.sampling_rate;
baseband_thread.set_sampling_rate(baseband_fs);
nsPerDecSamp = 1'000'000'000 / baseband_fs * 8; // Scaled it due to less array buffer sampes due to /8 decimation. 250 nseg (4Mhz) * 8
decim_0.configure(taps_200k_wfm_decim_0.taps);
decim_1.configure(taps_200k_wfm_decim_1.taps);
configured = true;
}
int main() {
EventDispatcher event_dispatcher{std::make_unique<SubGhzDProcessor>()};
event_dispatcher.run();
return 0;
}