/* * 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) = 31,875 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[159]); // symbol-phasor 225º im = (sine_table_i8[159 + 64]); // 159 rounded index = 96 + 256/4 = 159.3 break; case 192 ... 255: /* "11" */ re = (sine_table_i8[223]); // symbol-phasor 315º ; 223 rounded index = (315/360) * 255 =223.125 im = (sine_table_i8[((223 + 64) & 0xFF)]); // Max index 255, circular periodic conversion. 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; }