portapack-mayhem/firmware/baseband-tx/proc_rds.cpp

91 lines
2.4 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_rds.hpp"
#include "portapack_shared_memory.hpp"
#include "sine_table.hpp"
#include <cstdint>
void RDSProcessor::execute(const buffer_c8_t& buffer) {
for (size_t i = 0; i<buffer.count; i++) {
//Sample generation 2.28M/10=228kHz
if(s >= 9) {
s = 0;
if(sample_count >= SAMPLES_PER_BIT) {
cur_bit = (shared_memory.rdsdata[(bit_pos / 26) & 15]>>(25-(bit_pos % 26))) & 1;
prev_output = cur_output;
cur_output = prev_output ^ cur_bit;
int32_t *src = waveform_biphase;
int idx = in_sample_index;
for(int j=0; j<FILTER_SIZE; j++) {
val = (*src++);
if (cur_output) val = -val;
sample_buffer[idx++] += val;
if (idx >= SAMPLE_BUFFER_SIZE) idx = 0;
}
in_sample_index += SAMPLES_PER_BIT;
if (in_sample_index >= SAMPLE_BUFFER_SIZE) in_sample_index -= SAMPLE_BUFFER_SIZE;
bit_pos++;
sample_count = 0;
}
sample = sample_buffer[out_sample_index];
sample_buffer[out_sample_index] = 0;
out_sample_index++;
if (out_sample_index >= SAMPLE_BUFFER_SIZE) out_sample_index = 0;
//AM @ 228k/4=57kHz
switch (mphase) {
case 0:
case 2: sample = 0; break;
case 1: break;
case 3: sample = -sample; break;
}
mphase++;
if (mphase >= 4) mphase = 0;
sample_count++;
} else {
s++;
}
//FM
frq = (sample>>16) * 386760;
phase = (phase + frq);
sphase = phase + (256<<16);
//re = sintab[(sphase & 0x03FF0000)>>16];
//im = sintab[(phase & 0x03FF0000)>>16];
buffer.p[i] = {(int8_t)re,(int8_t)im};
}
}