kopia lustrzana https://github.com/jr3xnw/pico
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//2023_5_11 JR3XNW
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//pico RX uSDX Filters for each mode + AGC.
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const int speakerPin = 14; //Audio output GP14 pico 19-pin
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const int inputPinI = 26; //I Signal ADC0 pico31 pin
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const int inputPinQ = 27; //Q signal ADC1 pico332 pin
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const int sampleRate = 8000; //sample rate
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const int pwmFrequency = 30000; //PWM20000
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const int pushSwitchPin = 15; //Reception mode change push switch (LSB→USB→CW→AM)
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const float targetAmplitude = 0.5;//0.5-0.8
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const int numTaps = 31; //Number of filter taps
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const float hilbertCoeffs[numTaps] = {
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-0.001328193331496, 0.000000000000000, -0.002284533986424,
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0.000000000000000, -0.003313586555888, 0.000000000000000,
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-0.004387527896369, 0.000000000000000, -0.005470862958678,
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0.000000000000000, -0.006500296593254, 0.000000000000000,
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-0.007388063473212, 0.000000000000000, -0.008023180743934,
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0.000000000000000, -0.008266448739536, 0.000000000000000,
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-0.007942155320414, 0.000000000000000, -0.006729329308188,
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0.000000000000000, -0.004233803027843, 0.000000000000000,
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0.000000000000000, -0.005656339687371, 0.000000000000000,
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-0.016018448245468, 0.000000000000000, -0.031105779790221,
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0.000000000000000
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};
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const float lsbFilterCoeffs[numTaps] = {
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-1.57196597e-03, -1.45104171e-03, 1.12478657e-03, 4.46246491e-03,
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2.57714059e-03, -6.99319701e-03, -1.30293770e-02, 7.20713963e-18,
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2.47619628e-02, 2.56472800e-02, -1.88013680e-02, -6.76180323e-02,
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-3.71204042e-02, 1.08307805e-01, 2.91780827e-01, 3.75846238e-01,
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2.91780827e-01, 1.08307805e-01, -3.71204042e-02, -6.76180323e-02,
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-1.88013680e-02, 2.56472800e-02, 2.47619628e-02, 7.20713963e-18,
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-1.30293770e-02, -6.99319701e-03, 2.57714059e-03, 4.46246491e-03,
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1.12478657e-03, -1.45104171e-03, -1.57196597e-03
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};
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const float usbFilterCoeffs[numTaps] = {
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-1.57196597e-03, -1.45104171e-03, 1.12478657e-03, 4.46246491e-03,
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2.57714059e-03, -6.99319701e-03, -1.30293770e-02, 7.20713963e-18,
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2.47619628e-02, 2.56472800e-02, -1.88013680e-02, -6.76180323e-02,
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-3.71204042e-02, 1.08307805e-01, 2.91780827e-01, 3.75846238e-01,
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2.91780827e-01, 1.08307805e-01, -3.71204042e-02, -6.76180323e-02,
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-1.88013680e-02, 2.56472800e-02, 2.47619628e-02, 7.20713963e-18,
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-1.30293770e-02, -6.99319701e-03, 2.57714059e-03, 4.46246491e-03,
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1.12478657e-03, -1.45104171e-03, -1.57196597e-03
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};
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const float cwFilterCoeffs[numTaps] = {
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-6.47960382e-04, -1.44397905e-03, -2.70225797e-03, -4.44074475e-03,
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-6.19148454e-03, -6.95915901e-03, -5.37067609e-03, 2.39068677e-18,
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1.02068182e-02, 2.55224470e-02, 4.51695882e-02, 6.72889150e-02,
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8.91803923e-02, 1.07780639e-01, 1.20271316e-01, 1.24672294e-01,
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1.20271316e-01, 1.07780639e-01, 8.91803923e-02, 6.72889150e-02,
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4.51695882e-02, 2.55224470e-02, 1.02068182e-02, 2.39068677e-18,
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-5.37067609e-03, -6.95915901e-03, -6.19148454e-03, -4.44074475e-03,
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-2.70225797e-03, -1.44397905e-03, -6.47960382e-04
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};
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const float amFilterCoeffs[numTaps] = {
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-1.20126129e-03, 2.04889442e-03, -2.07510535e-03, 4.91080693e-18,
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4.75453597e-03, -9.87450755e-03, 9.95675888e-03, -1.43918829e-17,
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-1.89225390e-02, 3.62143751e-02, -3.46864198e-02, 2.48038628e-17,
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6.84829915e-02, -1.52932377e-01, 2.22972391e-01, 7.50524525e-01,
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2.22972391e-01, -1.52932377e-01, 6.84829915e-02, 2.48038628e-17,
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-3.46864198e-02, 3.62143751e-02, -1.89225390e-02, -1.43918829e-17,
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9.95675888e-03, -9.87450755e-03, 4.75453597e-03, 4.91080693e-18,
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-2.07510535e-03, 2.04889442e-03, -1.20126129e-03
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};
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float applyFilter(float input, const float *coeffs, float *buffer) {
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// Shift elements in the buffer
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for (int i = numTaps - 1; i > 0; i--) {
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buffer[i] = buffer[i - 1];
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}
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buffer[0] = input;
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float output = 0;
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for (int i = 0; i < numTaps; i++) {
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output += buffer[i] * coeffs[i];
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}
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return output;
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}
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float buffer[numTaps] = {0};
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float agcGain = 1.0;
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enum DemodulationMode { LSB, USB, CW, AM };
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DemodulationMode currentMode = LSB;
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void setup() {
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pinMode(25, OUTPUT); // pico built-in LED
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pinMode(speakerPin, OUTPUT);
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pinMode(inputPinI, INPUT);
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pinMode(inputPinQ, INPUT);
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pinMode(pushSwitchPin, INPUT_PULLUP);
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analogReadResolution(12);
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analogWriteResolution(8);
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analogWriteFreq(pwmFrequency);
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}
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float applyHilbertTransform(float input, const float *coeffs, float *buffer) {
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memmove(&buffer[1], &buffer[0], (numTaps - 1) * sizeof(float));
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buffer[0] = input;
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float output = 0;
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for (int i = 0; i < numTaps; i++) {
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output += buffer[i] * coeffs[i];
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}
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return output;
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}
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float applyAGC(float input) {
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float error = targetAmplitude - abs(input);
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agcGain += 0.001 * error;
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if (agcGain < 0.1) {
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agcGain = 0.1;
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}
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return input * agcGain;
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}
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float applyLowPassFilter(float input, const float *coeffs, float *buffer) {
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memmove(&buffer[1], &buffer[0], (numTaps - 1) * sizeof(float));
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buffer[0] = input;
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float output = 0;
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for (int i = 0; i < numTaps; i++) {
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output += buffer[i] * coeffs[i];
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}
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return output;
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}
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void loop() {
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digitalWrite(25, HIGH); // Built-in LED lights up during sampling
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float inputI, inputQ;
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float output = 0.0; // initialize output
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inputI = analogRead(inputPinI);
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inputQ = analogRead(inputPinQ);
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inputI = (inputI / 2047.5) - 1.0;
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inputQ = (inputQ / 2047.5) - 1.0;
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if (digitalRead(pushSwitchPin) == LOW) {
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delay(50); // Debounce delay
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currentMode = static_cast<DemodulationMode>((currentMode + 1) % 4);
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while (digitalRead(pushSwitchPin) == LOW); // Wait for switch release
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delay(50); // Debounce delay
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}
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// Apply the Hilbert Transform
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float hilbertOutput = applyFilter(output, hilbertCoeffs, buffer);
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switch (currentMode) {
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case LSB:
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output = inputI - inputQ;
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applyFilter(output, lsbFilterCoeffs, buffer);
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break;
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case USB:
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output = inputI + inputQ;
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applyFilter(output, usbFilterCoeffs, buffer);
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break;
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case CW:
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output = inputI * inputQ;
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applyFilter(output, cwFilterCoeffs, buffer);
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break;
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case AM:
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output = sqrt(inputI * inputI + inputQ * inputQ);
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applyFilter(output, amFilterCoeffs, buffer);
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break;
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}
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// Apply AGC
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float agcOutput = applyAGC(hilbertOutput);
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uint8_t pwmOutput = (uint8_t)((agcOutput + 1.0) * 127.5);
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analogWrite(speakerPin, pwmOutput);
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delayMicroseconds(1000000 / sampleRate);
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}
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