mayhem-firmware/firmware/baseband/proc_siggen.cpp
Brumi-2021 be7b402c95
Adding raw data stream BPSK - QPSK (#1534)
* Adding raw data stream BPSK - QPSK
* minor code compact
2023-10-30 11:32:34 +01:00

179 lines
7.8 KiB
C++

/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
* Copyright (C) 2017 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_siggen.hpp"
#include "portapack_shared_memory.hpp"
#include "sine_table_int8.hpp"
#include "event_m4.hpp"
#include <cstdint>
void SigGenProcessor::execute(const buffer_c8_t& buffer) {
if (!configured) return;
for (size_t i = 0; i < buffer.count; i++) {
if (!sample_count && auto_off) {
configured = false;
txprogress_message.done = true;
shared_memory.application_queue.push(txprogress_message);
} else
sample_count--;
if (tone_shape == 0) {
// CW
re = 127; // max. signed 8 bits value . (-128 ...+127), max. amplitude , static phasor at 0º
im = 0;
} else {
if (tone_shape == 1) {
// Sine
sample = (sine_table_i8[(tone_phase & 0xFF000000) >> 24]);
} else if (tone_shape == 2) {
// Triangle
int8_t a = (tone_phase & 0xFF000000) >> 24;
sample = (a & 0x80) ? ((a << 1) ^ 0xFF) - 0x80 : (a << 1) + 0x80;
} else if (tone_shape == 3) {
// Saw up
sample = ((tone_phase & 0xFF000000) >> 24);
} else if (tone_shape == 4) {
// Saw down
sample = ((tone_phase & 0xFF000000) >> 24) ^ 0xFF;
} else if (tone_shape == 5) {
// Square
sample = (((tone_phase & 0xFF000000) >> 24) & 0x80) ? 127 : -128;
} else if (tone_shape == 6) {
// Noise generator, pseudo random noise generator, 16 bits linear-feedback shift register (LFSR) algorithm, variant Fibonacci.
// https://en.wikipedia.org/wiki/Linear-feedback_shift_register
// 16 bits LFSR .taps: 16, 15, 13, 4 ;feedback polynomial: x^16 + x^15 + x^13 + x^4 + 1
// Periode 65535= 2^n-1, quite continuous .
if (counter == 0) { // we slow down the shift register, because the pseudo random noise clock freq was too high for modulator.
bit_16 = ((lfsr_16 >> 0) ^ (lfsr_16 >> 1) ^ (lfsr_16 >> 3) ^ (lfsr_16 >> 4) ^ ((lfsr_16 >> 12) & 1));
lfsr_16 = (lfsr_16 >> 1) | (bit_16 << 15);
sample = (lfsr_16 & 0x00FF); // main pseudo random noise generator.
}
if (counter == 5) { // after many empiric test, that combination mix of >>4 and >>5, gives a reasonable trade off white noise / good rf power level .
sample = ((lfsr_16 & 0b0000111111110000) >> 4); // just changing the spectrum shape .
}
if (counter == 10) {
sample = ((lfsr_16 & 0b0001111111100000) >> 5); // just changing the spectrum shape .
}
counter++;
if (counter == 15) {
counter = 0;
}
} else if (tone_shape == 7) {
// Digital BPSK consecutive 0,1,0,...continuous cycle, 1 bit/symbol, at rate of 2 symbols / Freq Tone Periode... without any Pulse shape at the moment .
re = (((tone_phase & 0xFF000000) >> 24) & 0x80) ? 127 : -128; // Sending 2 bits by Periode T of the GUI tone, alternative static phasor to 0, -180º , 0º
im = 0;
} else if (tone_shape == 8) {
// Digital QPSK consecutive 00, 01, 10, 11,00, ...continuous cycle ,2 bits/symbol, at rate of 4 symbols / Freq Tone Periode. not random., without any Pulse shape at the moment .
switch (((tone_phase & 0xFF000000) >> 24)) {
case 0 ... 63: // equivalent to 1/4 of total 360º degrees.
/* "00" */
re = (sine_table_i8[32]); // we are sending symbol-phasor 45º during 1/4 of the total periode
im = (sine_table_i8[32 + 64]); // 32 index = rounded (45º/360º * 255 total sin table steps)
break;
case 64 ... 127:
/* "01" */
re = (sine_table_i8[96]); // symbol-phasor 135º
im = (sine_table_i8[96 + 64]); // 96 index = 32 + 256/4
break;
break;
case 128 ... 191:
/* "10" */
re = (sine_table_i8[160]); // symbol-phasor 225º
im = (sine_table_i8[160 + 64]); // 160 index = 96 + 256/4
break;
case 192 ... 255:
/* "11" */
re = (sine_table_i8[224]); // symbol-phasor 315º , (315/360) * 255
im = (sine_table_i8[224 + 64]);
break;
default:
break;
}
}
if (tone_shape != 6) { //(all except Pseudo Random White Noise). We are in (1):periodic signals or (2):BPSK/QPSK , in both cases ,we need Tone updated acum sum phases to modulate in FM / or control phasor phase (BPSK & QPSK.)
tone_phase += tone_delta; // In periodic signals(Sine/triangle/square) we are using to FM mod. in BPSK-QSPK we are using to calculate each 1/4 of the periode.
}
if (tone_shape < 7) { // All Option shape signals except BPSK(7) & QPSK(8) we are modulating in FM. (Those two has phase shift modulation XPSK , not FM )
// Do FM modulation
delta = sample * fm_delta;
phase += delta;
sphase = phase + (64 << 24);
re = (sine_table_i8[(sphase & 0xFF000000) >> 24]); // sin LUT is not dealing with decimals , output range [-128 ,...127]
im = (sine_table_i8[(phase & 0xFF000000) >> 24]);
}
}
buffer.p[i] = {re, im};
}
};
void SigGenProcessor::on_message(const Message* const msg) {
const auto message = *reinterpret_cast<const SigGenConfigMessage*>(msg);
switch (msg->id) {
case Message::ID::SigGenConfig:
if (!message.bw) {
configured = false;
return;
}
if (message.duration) {
sample_count = message.duration;
auto_off = true;
} else
auto_off = false;
fm_delta = message.bw * (0xFFFFFFULL / 1536000);
tone_shape = message.shape;
// lfsr = seed_value ; // Finally not used , init lfsr 8 bits.
lfsr_16 = seed_value_16; // init lfsr 16 bits.
configured = true;
break;
case Message::ID::SigGenTone:
tone_delta = reinterpret_cast<const SigGenToneMessage*>(msg)->tone_delta;
break;
default:
break;
}
}
int main() {
EventDispatcher event_dispatcher{std::make_unique<SigGenProcessor>()};
event_dispatcher.run();
return 0;
}