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Merge pull request #946 from Brumi-2021/noise_Signal_Generator_LFSR_polynomial_of_16_32_bits

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Leaving only 1 Noise signal generator GUI option , (the best one , using  LFSR polynomial of 16 bits)
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gullradriel 2023-05-03 13:57:06 +02:00 committed by GitHub
commit f7a5f2c437
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3 changed files with 46 additions and 41 deletions
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34
firmware/application/apps/ui_siggen.hpp
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@ -48,29 +48,27 @@ private:
void update_tone();
void on_tx_progress(const uint32_t progress, const bool done);
const std::string shape_strings[9] = {
"CW ",
"Sine ",
"Triangle ",
"Saw up ",
"Saw down ",
"Square ",
"Noise n20Khz",
"Noise n10khz",
"Noise n5khz "
const std::string shape_strings[7] = {
"CW-just carrier",
"Sine signal ",
"Triangle signal",
"Saw up signal ",
"Saw down signal",
"Square signal ",
"Noise signal " // using 16 bits LFSR register, 16 order polynomial feedback.
};
bool auto_update { false };
Labels labels {
{ { 6 * 8, 4 + 10 }, "Shape:", Color::light_grey() },
{ { 7 * 8, 7 * 8 }, "Tone: Hz", Color::light_grey() },
{ { 3 * 8, 4 + 10 }, "Shape:", Color::light_grey() },
{ { 6 * 8, 7 * 8 }, "Tone: Hz", Color::light_grey() },
{ { 22 * 8, 15 * 8 + 4 }, "s.", Color::light_grey() },
{ { 8 * 8, 20 * 8 }, "Modulation: FM", Color::light_grey() }
};
ImageOptionsField options_shape {
{ 13 * 8, 4, 32, 32 },
{ 10 * 8, 4, 32, 32 },
Color::white(),
Color::black(),
{
@ -80,14 +78,12 @@ private:
{ &bitmap_sig_saw_up, 3 },
{ &bitmap_sig_saw_down, 4 },
{ &bitmap_sig_square, 5 },
{ &bitmap_sig_noise, 6 },
{ &bitmap_sig_noise, 7 },
{ &bitmap_sig_noise, 8 }
{ &bitmap_sig_noise, 6 }
}
};
Text text_shape {
{ 18 * 8, 4 + 10, 8 * 8, 16 },
{ 15 * 8, 4 + 10, 8 * 8, 16 },
""
};
@ -98,12 +94,12 @@ private:
};
Button button_update {
{ 6 * 8, 10 * 8, 8 * 8, 3 * 8 },
{ 5 * 8, 10 * 8, 8 * 8, 3 * 8 },
"Update"
};
Checkbox checkbox_auto {
{ 16 * 8, 10 * 8 },
{ 15 * 8, 10 * 8 },
4,
"Auto"
};

38
firmware/baseband/proc_siggen.cpp
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@ -61,23 +61,29 @@ void SigGenProcessor::execute(const buffer_c8_t& buffer) {
} else if (tone_shape == 5) {
// Square
sample = (((tone_phase & 0xFF000000) >> 24) & 0x80) ? 127 : -128;
} else if (tone_shape == 6) { // taps: 6 5; feedback polynomial: x^6 + x^5 + 1 , Periode 63 = 2^n-1,it generates armonincs n x 20Khz
// White Noise generator, pseudo random noise generator, 8 bits linear-feedback shift register (LFSR) algorithm, variant Fibonacci.
} 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
bit = ((lfsr >> 2) ^ (lfsr >> 3)) & 1;
lfsr = (lfsr >> 1) | (bit << 7);
sample = lfsr;
} else if (tone_shape == 7) { // taps: 7 6; feedback polynomial: x^7 + x^6 + 1 , Periode 127 = 2^n-1,it generates armonincs n x 10Khz
bit = ((lfsr >> 1) ^ (lfsr >> 2)) & 1;
lfsr = (lfsr >> 1) | (bit << 7);
sample = lfsr;
} else if (tone_shape == 8) { //taps:8,6,5,4;feedback polynomial: x^8 + x^6 + x^5 + x^4 + 1,Periode 255= 2^n-1, armonics n x 5khz
bit = ((lfsr >> 0) ^ (lfsr >> 2) ^ (lfsr >> 3) ^ (lfsr >> 4)) & 1;
lfsr = (lfsr >> 1) | (bit << 7);
sample = lfsr;
// 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;
}
}
if (tone_shape < 6) {
if (tone_shape < 6) { // we are in periodic signals, we need tone phases update.
tone_phase += tone_delta;
}
@ -114,8 +120,8 @@ void SigGenProcessor::on_message(const Message* const msg) {
fm_delta = message.bw * (0xFFFFFFULL / 1536000);
tone_shape = message.shape;
// lfsr = 0x54DF0119;
lfsr = seed_value ;
// lfsr = seed_value ; // Finally not used , init lfsr 8 bits.
lfsr_16 = seed_value_16; // init lfsr 16 bits.
configured = true;
break;

11
firmware/baseband/proc_siggen.hpp
View File

@ -42,10 +42,13 @@ private:
uint8_t tone_shape { };
uint32_t sample_count { 0 };
bool auto_off { };
int32_t phase { 0 }, sphase { 0 }, delta { 0 }; // they may have sign .
int8_t sample { 0 }, re { 0 }, im { 0 }; // they may have sign .
uint8_t seed_value = {0x56}; // seed : any nonzero start state will work.
uint8_t lfsr { }, bit { }; // bit must be 8-bit to allow bit<<7 later in the code */
int32_t phase { 0 }, sphase { 0 }, delta { 0 }; // they may have sign in the pseudo random sample generation.
int8_t sample { 0 }, re { 0 }, im { 0 }; // they have sign + and -.
uint16_t seed_value_16 = {0xACE1}; // seed 16 bits lfsr : any nonzero start state will work.
uint16_t lfsr_16 { }, bit_16 { }; // bit must be 16-bit to allow bit<<15 later in the code */
uint8_t counter {0};
// uint8_t seed_value = {0x56}; // Finally not used lfsr of 8 bits , seed 8blfsr : any nonzero start state will work.
// uint8_t lfsr { }, bit { }; // Finally not used lfsr of 8 bits , bit must be 8-bit to allow bit<<7 later in the code */
TXProgressMessage txprogress_message { };
};