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Solving Noise generation in Signal gen App
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cb93f2636e
commit
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@ -48,14 +48,16 @@ private:
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void update_tone();
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void update_tone();
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void on_tx_progress(const uint32_t progress, const bool done);
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void on_tx_progress(const uint32_t progress, const bool done);
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const std::string shape_strings[7] = {
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const std::string shape_strings[9] = {
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"CW",
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"CW ",
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"Sine",
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"Sine ",
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"Triangle",
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"Triangle ",
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"Saw up",
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"Saw up ",
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"Saw down",
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"Saw down ",
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"Square",
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"Square ",
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"Noise"
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"Noise n20Khz",
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"Noise n10khz",
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"Noise n5khz "
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};
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};
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bool auto_update { false };
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bool auto_update { false };
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@ -78,7 +80,9 @@ private:
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{ &bitmap_sig_saw_up, 3 },
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{ &bitmap_sig_saw_up, 3 },
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{ &bitmap_sig_saw_down, 4 },
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{ &bitmap_sig_saw_down, 4 },
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{ &bitmap_sig_square, 5 },
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{ &bitmap_sig_square, 5 },
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{ &bitmap_sig_noise, 6 }
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{ &bitmap_sig_noise, 6 },
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{ &bitmap_sig_noise, 7 },
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{ &bitmap_sig_noise, 8 }
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}
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}
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};
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};
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@ -49,7 +49,7 @@ void SigGenProcessor::execute(const buffer_c8_t& buffer) {
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// Sine
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// Sine
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sample = (sine_table_i8[(tone_phase & 0xFF000000) >> 24]);
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sample = (sine_table_i8[(tone_phase & 0xFF000000) >> 24]);
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} else if (tone_shape == 2) {
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} else if (tone_shape == 2) {
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// Tri
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// Triangle
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int8_t a = (tone_phase & 0xFF000000) >> 24;
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int8_t a = (tone_phase & 0xFF000000) >> 24;
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sample = (a & 0x80) ? ((a << 1) ^ 0xFF) - 0x80 : (a << 1) + 0x80;
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sample = (a & 0x80) ? ((a << 1) ^ 0xFF) - 0x80 : (a << 1) + 0x80;
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} else if (tone_shape == 3) {
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} else if (tone_shape == 3) {
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@ -61,24 +61,34 @@ void SigGenProcessor::execute(const buffer_c8_t& buffer) {
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} else if (tone_shape == 5) {
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} else if (tone_shape == 5) {
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// Square
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// Square
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sample = (((tone_phase & 0xFF000000) >> 24) & 0x80) ? 127 : -128;
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sample = (((tone_phase & 0xFF000000) >> 24) & 0x80) ? 127 : -128;
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} else if (tone_shape == 6) {
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} 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
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// Noise
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// White Noise generator, pseudo random noise generator, 8 bits linear-feedback shift register (LFSR) algorithm, variant Fibonacci.
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sample = (lfsr & 0xFF000000) >> 24;
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// https://en.wikipedia.org/wiki/Linear-feedback_shift_register
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feedback = ((lfsr >> 31) ^ (lfsr >> 29) ^ (lfsr >> 15) ^ (lfsr >> 11)) & 1;
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bit = ((lfsr >> 2) ^ (lfsr >> 3)) & 1;
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lfsr = (lfsr << 1) | feedback;
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lfsr = (lfsr >> 1) | (bit << 7);
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if (!lfsr) lfsr = 0x1337; // Shouldn't do this :(
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sample = lfsr;
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} 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
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bit = ((lfsr >> 1) ^ (lfsr >> 2)) & 1;
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lfsr = (lfsr >> 1) | (bit << 7);
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sample = lfsr;
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} 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
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bit = ((lfsr >> 0) ^ (lfsr >> 2) ^ (lfsr >> 3) ^ (lfsr >> 4)) & 1;
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lfsr = (lfsr >> 1) | (bit << 7);
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sample = lfsr;
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}
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}
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tone_phase += tone_delta;
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if (tone_shape < 6) {
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tone_phase += tone_delta;
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}
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// Do FM
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// Do FM modulation
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delta = sample * fm_delta;
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delta = sample * fm_delta;
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phase += delta;
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phase += delta;
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sphase = phase + (64 << 24);
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sphase = phase + (64 << 24);
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re = (sine_table_i8[(sphase & 0xFF000000) >> 24]);
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re = (sine_table_i8[(sphase & 0xFF000000) >> 24]);
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im = (sine_table_i8[(phase & 0xFF000000) >> 24]);
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im = (sine_table_i8[( phase & 0xFF000000) >> 24]);
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}
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}
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buffer.p[i] = {re, im};
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buffer.p[i] = {re, im};
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@ -104,7 +114,8 @@ void SigGenProcessor::on_message(const Message* const msg) {
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fm_delta = message.bw * (0xFFFFFFULL / 1536000);
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fm_delta = message.bw * (0xFFFFFFULL / 1536000);
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tone_shape = message.shape;
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tone_shape = message.shape;
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lfsr = 0x54DF0119;
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// lfsr = 0x54DF0119;
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lfsr = seed_value ;
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configured = true;
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configured = true;
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break;
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break;
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@ -38,13 +38,14 @@ private:
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BasebandThread baseband_thread { 1536000, this, NORMALPRIO + 20, baseband::Direction::Transmit };
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BasebandThread baseband_thread { 1536000, this, NORMALPRIO + 20, baseband::Direction::Transmit };
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uint32_t tone_delta { 0 }, fm_delta { };
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uint32_t tone_delta { 0 }, fm_delta { },tone_phase { 0 };
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uint32_t lfsr { }, feedback { }, tone_shape { };
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uint8_t tone_shape { };
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uint32_t sample_count { 0 };
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uint32_t sample_count { 0 };
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bool auto_off { };
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bool auto_off { };
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uint32_t tone_phase { 0 }, phase { 0 }, delta { 0 }, sphase { 0 };
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int32_t phase { 0 }, sphase { 0 }, delta { 0 }; // they may have sign .
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int8_t sample { 0 };
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int8_t sample { 0 }, re { 0 }, im { 0 }; // they may have sign .
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int8_t re { 0 }, im { 0 };
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uint8_t seed_value = {0x56}; // seed : any nonzero start state will work.
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uint8_t lfsr { }, bit { }; // bit must be 8-bit to allow bit<<7 later in the code */
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TXProgressMessage txprogress_message { };
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TXProgressMessage txprogress_message { };
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};
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};
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