mirror of
https://github.com/eried/portapack-mayhem.git
synced 2024-10-01 01:26:06 -04:00
4aae77f565
Use single set of taps for positive and negative filters. Reverse taps (since new samples are pushed into buffer from the high end). Make complex multiply explicit to avoid fancy but irrelevant arithmetic checks. Compute negative filter from conjugation of positive filter taps. Move filter power and difference calculations into MatchedFilter.
114 lines
3.3 KiB
C++
114 lines
3.3 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_fsk.hpp"
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#include "portapack_shared_memory.hpp"
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#include "i2s.hpp"
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using namespace lpc43xx;
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FSKProcessor::FSKProcessor(
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MessageHandlerMap& message_handlers
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) : message_handlers(message_handlers)
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{
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message_handlers.register_handler(Message::ID::FSKConfiguration,
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[this](const Message* const p) {
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auto m = reinterpret_cast<const FSKConfigurationMessage*>(p);
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this->configure(m->configuration);
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}
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);
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}
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FSKProcessor::~FSKProcessor() {
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message_handlers.unregister_handler(Message::ID::FSKConfiguration);
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}
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void FSKProcessor::configure(const FSKConfiguration new_configuration) {
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// TODO: Matched filter characteristics are hard-coded for the moment. YUCK!
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clock_recovery.configure(sampling_rate / 4, new_configuration.symbol_rate);
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packet_builder.configure(
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{ new_configuration.access_code, new_configuration.access_code_length, new_configuration.access_code_tolerance },
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{ new_configuration.unstuffing_pattern, new_configuration.unstuffing_length }
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);
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}
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void FSKProcessor::execute(buffer_c8_t buffer) {
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/* 2.4576MHz, 2048 samples */
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auto decimator_out = decimator.execute(buffer);
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/* 153.6kHz, 128 samples */
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const buffer_c16_t work_baseband_buffer {
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(complex16_t*)decimator_out.p,
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decimator_out.count
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};
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/* 153.6kHz complex<int16_t>[128]
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* -> FIR filter, <?kHz (?fs) pass, gain 1.0
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* -> 76.8kHz int16_t[64] */
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auto channel = channel_filter.execute(decimator_out, work_baseband_buffer);
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/* 76.8kHz, 64 samples */
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feed_channel_stats(channel);
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feed_channel_spectrum(
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channel,
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decimator_out.sampling_rate * channel_filter_taps.pass_frequency_normalized,
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decimator_out.sampling_rate * channel_filter_taps.stop_frequency_normalized
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);
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// 76.8k
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// TODO: Factor out this hidden decimation magic.
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for(size_t i=0; i<channel.count; i+=4) {
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// TODO: No idea why implicit cast int16_t->float is not allowed.
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const std::complex<float> sample {
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static_cast<float>(channel.p[i].real()),
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static_cast<float>(channel.p[i].imag())
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};
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if( mf.execute_once(sample) ) {
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clock_recovery(mf.get_output());
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}
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}
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i2s::i2s0::tx_mute();
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}
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void FSKProcessor::consume_symbol(
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const float raw_symbol
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) {
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const uint_fast8_t sliced_symbol = (raw_symbol >= 0.0f) ? 1 : 0;
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const auto decoded_symbol = nrzi_decode(sliced_symbol);
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packet_builder.execute(decoded_symbol);
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}
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void FSKProcessor::payload_handler(
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const std::bitset<1024>& payload,
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const size_t bits_received
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) {
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FSKPacketMessage message;
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message.packet.payload = payload;
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message.packet.bits_received = bits_received;
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shared_memory.application_queue.push(message);
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}
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