mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
synced 2026-09-09 00:09:06 +00:00
Merge branch 'next' of https://github.com/Brumi-2021/portapack-mayhem into next
This commit is contained in:
Brumi-2021
@@ -32,115 +32,125 @@ using namespace adsb;
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void ADSBRXProcessor::execute(const buffer_c8_t& buffer) {
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int8_t re, im;
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float mag;
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uint32_t mag;
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uint32_t c;
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uint8_t level, bit, byte { };
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//bool confidence;
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bool first_in_window, last_in_window;
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uint8_t bit, byte{};
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// This is called at 2M/2048 = 977Hz
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// One pulse = 500ns = 2 samples
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// One bit = 2 pulses = 1us = 4 samples
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if (!configured) return;
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for (size_t i = 0; i < buffer.count; i++) {
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// Compute sample's magnitude
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re = buffer.p[i].real();
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im = buffer.p[i].imag();
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mag = __builtin_sqrtf((re * re) + (im * im)) * k;
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// Only used for preamble detection and visualisation
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level = (mag < 0.3) ? 0 : // Blank weak signals
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(mag > prev_mag) ? 1 : 0;
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re = (int32_t)buffer.p[i].real(); // make re float and scale it
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im = (int32_t)buffer.p[i].imag(); // make re float and scale it
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mag = ((uint32_t)(re*re) + (uint32_t)(im*im));
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if (decoding) {
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// Decode
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// 1 bit lasts 2 samples
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if (sample_count & 1) {
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if ((prev_mag < threshold_low) && (mag < threshold_low)) {
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// Both under window, silence.
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if (null_count > 3) {
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const ADSBFrameMessage message(frame);
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shared_memory.application_queue.push(message);
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decoding = false;
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} else
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null_count++;
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//confidence = false;
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if (prev_mag > mag)
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bit = 1;
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else
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bit = 0;
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} else {
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null_count = 0;
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first_in_window = ((prev_mag >= threshold_low) && (prev_mag <= threshold_high));
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last_in_window = ((mag >= threshold_low) && (mag <= threshold_high));
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if ((first_in_window && !last_in_window) || (!first_in_window && last_in_window)) {
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//confidence = true;
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if (prev_mag > mag)
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bit = 1;
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else
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bit = 0;
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} else {
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//confidence = false;
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if (prev_mag > mag)
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bit = 1;
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else
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bit = 0;
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}
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if (bit_count >= msgLen)
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{
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const ADSBFrameMessage message(frame, amp);
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shared_memory.application_queue.push(message);
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decoding = false;
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bit = (prev_mag > mag) ? 1 : 0;
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}
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else
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{
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//confidence = true;
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bit = (prev_mag > mag) ? 1 : 0;
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}
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byte = bit | (byte << 1);
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bit_count++;
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// Perform checks at the end of the first byte
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if (!(bit_count & 7)) {
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// Got one byte
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// Store the byte
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frame.push_byte(byte);
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}
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}
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// Check at the end of the first byte of the message
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uint8_t df = (byte >> 3);
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if ( (bit_count == 8) && !(df & 0x10) ) {
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msgLen = 56; // DFs 16 or greater are long 112. DFs 15 or less are short 56.
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}
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// Abondon all frames that arent DF17 or DF18 extended squitters
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if ( (bit_count == 8) && !((df == 17)||(df == 18)) ) {
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decoding = false;
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bit = (prev_mag > mag) ? 1 : 0;
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frame.clear();
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}
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} // last bit of a byte
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} // Second sample of each bit
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sample_count++;
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} else {
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// Look for preamble
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// Shift
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for (c = 0; c < (ADSB_PREAMBLE_LENGTH - 1); c++)
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shifter[c] = shifter[c + 1];
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shifter[15] = std::make_pair(mag, level);
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// Compare
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for (c = 0; c < ADSB_PREAMBLE_LENGTH; c++) {
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if (shifter[c].second != adsb_preamble[c])
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break;
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}
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if (c == ADSB_PREAMBLE_LENGTH) {
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decoding = true;
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sample_count = 0;
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null_count = 0;
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bit_count = 0;
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frame.clear();
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// Compute preamble pulses power to set thresholds
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threshold = (shifter[0].first + shifter[2].first + shifter[7].first + shifter[9].first) / 4;
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threshold_high = threshold * 1.414; // +3dB
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threshold_low = threshold * 0.707; // -3dB
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}
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}
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// Continue looking for preamble even if in a packet
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// switch is new preamble id higher magnitude
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// Shift the preamble
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for (c = 0; c < (ADSB_PREAMBLE_LENGTH ); c++) { shifter[c] = shifter[c + 1]; }
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shifter[ADSB_PREAMBLE_LENGTH] = mag;
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// First check of relations between the first 10 samples
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// representing a valid preamble. We don't even investigate further
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// if this simple test is not passed
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if (shifter[0] < shifter[1] &&
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shifter[1] > shifter[2] &&
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shifter[2] < shifter[3] &&
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shifter[3] > shifter[4] &&
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shifter[4] < shifter[1] &&
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shifter[5] < shifter[1] &&
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shifter[6] < shifter[1] &&
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shifter[7] < shifter[1] &&
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shifter[8] > shifter[9] &&
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shifter[9] < shifter[10] &&
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shifter[10]> shifter[11] )
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{
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// The samples between the two spikes must be < than the average
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// of the high spikes level. We don't test bits too near to
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// the high levels as signals can be out of phase so part of the
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// energy can be in the near samples
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int32_t thisAmp = (shifter[1] + shifter[3] + shifter[8] + shifter[10]);
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int32_t high = thisAmp / 9;
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if (
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shifter[5] < high &&
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shifter[6] < high &&
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// Similarly samples in the range 11-13 must be low, as it is the
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// space between the preamble and real data. Again we don't test
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// bits too near to high levels, see above
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shifter[12] < high &&
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shifter[13] < high &&
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shifter[14] < high )
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{
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if ((decoding == false) || // New preamble
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((decoding == true) && (thisAmp > amp))) // Higher power than existing packet
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{
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decoding = true;
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msgLen = 112;
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amp = thisAmp;
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sample_count = 0;
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bit_count = 0;
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frame.clear();
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}
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} // 4 & 5 low and 11-14 low
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} // Check for preamble pattern
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// Store mag for next time
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prev_mag = mag;
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}
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}
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void ADSBRXProcessor::on_message(const Message* const message) {
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if (message->id == Message::ID::ADSBConfigure) {
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null_count = 0;
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bit_count = 0;
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sample_count = 0;
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decoding = false;
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@@ -148,8 +158,10 @@ void ADSBRXProcessor::on_message(const Message* const message) {
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}
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}
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#ifndef _WIN32
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int main() {
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EventDispatcher event_dispatcher { std::make_unique<ADSBRXProcessor>() };
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event_dispatcher.run();
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return 0;
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}
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#endif
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@@ -40,8 +40,6 @@ public:
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void on_message(const Message* const message) override;
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private:
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static constexpr float k = 1.0f / 128.0f;
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static constexpr size_t baseband_fs = 2000000;
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BasebandThread baseband_thread { baseband_fs, this, NORMALPRIO + 20, baseband::Direction::Receive };
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@@ -49,16 +47,17 @@ private:
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ADSBFrame frame { };
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bool configured { false };
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float prev_mag { 0 };
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float threshold { }, threshold_low { }, threshold_high { };
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size_t null_count { 0 }, bit_count { 0 }, sample_count { 0 };
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std::pair<float, uint8_t> shifter[ADSB_PREAMBLE_LENGTH];
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uint32_t prev_mag { 0 };
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size_t bit_count { 0 }, sample_count { 0 };
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size_t msgLen{ 112 };
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uint32_t shifter[ADSB_PREAMBLE_LENGTH+1];
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bool decoding { };
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bool preamble { }, active { };
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uint16_t bit_pos { 0 };
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uint8_t cur_bit { 0 };
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uint32_t sample { 0 };
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int8_t re { }, im { };
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int32_t re { }, im { };
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int32_t amp {0};
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};
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#endif
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+464
-106
@@ -28,6 +28,9 @@
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#include <cstdint>
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#include <cstddef>
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#include <algorithm> // std::max
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#include <cmath>
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void POCSAGProcessor::execute(const buffer_c8_t& buffer) {
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// This is called at 1500Hz
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@@ -39,114 +42,45 @@ void POCSAGProcessor::execute(const buffer_c8_t& buffer) {
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const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
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const auto channel_out = channel_filter.execute(decim_1_out, dst_buffer);
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auto audio = demod.execute(channel_out, audio_buffer);
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//audio_output.write(audio);
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smooth.Process(audio.p, audio.count); // Smooth the data to make decoding more accurate
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audio_output.write(audio);
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for (uint32_t c = 0; c < 16; c++) {
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const int32_t sample_int = audio.p[c] * 32768.0f;
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const int32_t audio_sample = __SSAT(sample_int, 16);
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slicer_sr <<= 1;
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if (phase == 0)
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slicer_sr |= (audio_sample < 0); // Do we need hysteresis ?
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else
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slicer_sr |= !(audio_sample < 0);
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// Detect transitions to adjust clock
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if ((slicer_sr ^ (slicer_sr >> 1)) & 1) {
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if (sphase < (0x8000u - sphase_delta_half))
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sphase += sphase_delta_eighth;
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else
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sphase -= sphase_delta_eighth;
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}
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sphase += sphase_delta;
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// Symbol time elapsed
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if (sphase >= 0x10000u) {
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sphase &= 0xFFFFu;
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rx_data <<= 1;
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rx_data |= (slicer_sr & 1);
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switch (rx_state) {
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case WAITING:
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if (rx_data == 0xAAAAAAAA) {
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rx_state = PREAMBLE;
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sync_timeout = 0;
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}
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break;
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case PREAMBLE:
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if (sync_timeout < POCSAG_TIMEOUT) {
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sync_timeout++;
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processDemodulatedSamples(audio.p, 16);
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extractFrames();
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if (rx_data == POCSAG_SYNCWORD) {
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packet.clear();
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codeword_count = 0;
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rx_bit = 0;
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msg_timeout = 0;
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rx_state = SYNC;
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}
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} else {
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// Timeout here is normal (end of message)
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rx_state = WAITING;
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//push_packet(pocsag::PacketFlag::TIMED_OUT);
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}
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break;
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case SYNC:
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if (msg_timeout < POCSAG_BATCH_LENGTH) {
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msg_timeout++;
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rx_bit++;
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if (rx_bit >= 32) {
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rx_bit = 0;
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// Got a complete codeword
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//pocsag_brute_repair(&s->l2.pocsag, &rx_data);
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packet.set(codeword_count, rx_data);
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if (codeword_count < 15) {
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codeword_count++;
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} else {
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push_packet(pocsag::PacketFlag::NORMAL);
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rx_state = PREAMBLE;
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sync_timeout = 0;
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}
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}
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} else {
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packet.set(0, codeword_count); // Replace first codeword with count, for debug
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push_packet(pocsag::PacketFlag::TIMED_OUT);
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rx_state = WAITING;
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}
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break;
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default:
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break;
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}
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}
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}
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}
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void POCSAGProcessor::push_packet(pocsag::PacketFlag flag) {
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packet.set_bitrate(bitrate);
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packet.set_flag(flag);
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packet.set_timestamp(Timestamp::now());
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const POCSAGPacketMessage message(packet);
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shared_memory.application_queue.push(message);
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// ====================================================================
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//
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// ====================================================================
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int POCSAGProcessor::OnDataWord(uint32_t word, int pos)
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{
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packet.set(pos, word);
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return 0;
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}
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// ====================================================================
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//
|
||||
// ====================================================================
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int POCSAGProcessor::OnDataFrame(int len, int baud)
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{
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if (len > 0)
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{
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packet.set_bitrate(baud);
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packet.set_flag(pocsag::PacketFlag::NORMAL);
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packet.set_timestamp(Timestamp::now());
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const POCSAGPacketMessage message(packet);
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shared_memory.application_queue.push(message);
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}
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return 0;
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}
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void POCSAGProcessor::on_message(const Message* const message) {
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if (message->id == Message::ID::POCSAGConfigure)
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configure(*reinterpret_cast<const POCSAGConfigureMessage*>(message));
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configure();
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||||
}
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||||
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void POCSAGProcessor::configure(const POCSAGConfigureMessage& message) {
|
||||
void POCSAGProcessor::configure() {
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constexpr size_t decim_0_input_fs = baseband_fs;
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constexpr size_t decim_0_output_fs = decim_0_input_fs / decim_0.decimation_factor;
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||||
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||||
@@ -162,18 +96,442 @@ void POCSAGProcessor::configure(const POCSAGConfigureMessage& message) {
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||||
decim_1.configure(taps_11k0_decim_1.taps, 131072);
|
||||
channel_filter.configure(taps_11k0_channel.taps, 2);
|
||||
demod.configure(demod_input_fs, 4500);
|
||||
//audio_output.configure(false);
|
||||
// Smoothing should be roughly sample rate over max baud
|
||||
// 24k / 3.2k is 7.5
|
||||
smooth.SetSize(8);
|
||||
audio_output.configure(false);
|
||||
|
||||
bitrate = message.bitrate;
|
||||
phase = message.phase;
|
||||
sphase_delta = 0x10000u * bitrate / POCSAG_AUDIO_RATE;
|
||||
sphase_delta_half = sphase_delta / 2; // Just for speed
|
||||
sphase_delta_eighth = sphase_delta / 8;
|
||||
|
||||
rx_state = WAITING;
|
||||
// Set up the frame extraction, limits of baud
|
||||
setFrameExtractParams(demod_input_fs, 4000, 300, 32);
|
||||
|
||||
// Mark the class as ready to accept data
|
||||
configured = true;
|
||||
}
|
||||
|
||||
|
||||
|
||||
// -----------------------------
|
||||
// Frame extractraction methods
|
||||
// -----------------------------
|
||||
#define BAUD_STABLE (104)
|
||||
#define MAX_CONSEC_SAME (32)
|
||||
#define MAX_WITHOUT_SINGLE (64)
|
||||
#define MAX_BAD_TRANS (10)
|
||||
|
||||
#define M_SYNC (0x7cd215d8)
|
||||
#define M_NOTSYNC (0x832dea27)
|
||||
|
||||
#define M_IDLE (0x7a89c197)
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
inline int bitsDiff(unsigned long left, unsigned long right)
|
||||
{
|
||||
unsigned long xord = left ^ right;
|
||||
int count = 0;
|
||||
for (int i = 0; i < 32; i++)
|
||||
{
|
||||
if ((xord & 0x01) != 0) ++count;
|
||||
xord = xord >> 1;
|
||||
}
|
||||
return(count);
|
||||
|
||||
}
|
||||
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
void POCSAGProcessor::initFrameExtraction()
|
||||
{
|
||||
m_averageSymbolLen_1024 = m_maxSymSamples_1024;
|
||||
m_lastStableSymbolLen_1024 = m_minSymSamples_1024;
|
||||
|
||||
m_badTransitions = 0;
|
||||
m_bitsStart = 0;
|
||||
m_bitsEnd = 0;
|
||||
m_inverted = false;
|
||||
|
||||
resetVals();
|
||||
}
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
void POCSAGProcessor::resetVals()
|
||||
{
|
||||
// Reset the parameters
|
||||
// --------------------
|
||||
m_goodTransitions = 0;
|
||||
m_badTransitions = 0;
|
||||
m_averageSymbolLen_1024 = m_maxSymSamples_1024;
|
||||
m_shortestGoodTrans_1024 = m_maxSymSamples_1024;
|
||||
m_valMid = 0;
|
||||
|
||||
// And reset the counts
|
||||
// --------------------
|
||||
m_lastTransPos_1024 = 0;
|
||||
m_lastBitPos_1024 = 0;
|
||||
m_lastSample = 0;
|
||||
m_sampleNo = 0;
|
||||
m_nextBitPos_1024 = m_maxSymSamples_1024;
|
||||
m_nextBitPosInt = (long)m_nextBitPos_1024;
|
||||
|
||||
// Extraction
|
||||
m_fifo.numBits = 0;
|
||||
m_gotSync = false;
|
||||
m_numCode = 0;
|
||||
}
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
void POCSAGProcessor::setFrameExtractParams(long a_samplesPerSec, long a_maxBaud, long a_minBaud, long maxRunOfSameValue)
|
||||
{
|
||||
m_samplesPerSec = a_samplesPerSec;
|
||||
m_minSymSamples_1024 = (uint32_t)(1024.0f * (float)a_samplesPerSec / (float)a_maxBaud);
|
||||
m_maxSymSamples_1024 = (uint32_t)(1024.0f*(float)a_samplesPerSec / (float)a_minBaud);
|
||||
m_maxRunOfSameValue = maxRunOfSameValue;
|
||||
|
||||
m_shortestGoodTrans_1024 = m_maxSymSamples_1024;
|
||||
m_averageSymbolLen_1024 = m_maxSymSamples_1024;
|
||||
m_lastStableSymbolLen_1024 = m_minSymSamples_1024;
|
||||
|
||||
m_nextBitPos_1024 = m_averageSymbolLen_1024 / 2;
|
||||
m_nextBitPosInt = m_nextBitPos_1024 >> 10;
|
||||
|
||||
initFrameExtraction();
|
||||
}
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
int POCSAGProcessor::processDemodulatedSamples(float * sampleBuff, int noOfSamples)
|
||||
{
|
||||
bool transition = false;
|
||||
uint32_t samplePos_1024 = 0;
|
||||
uint32_t len_1024 = 0;
|
||||
|
||||
// Loop through the block of data
|
||||
// ------------------------------
|
||||
for (int pos = 0; pos < noOfSamples; ++pos)
|
||||
{
|
||||
m_sample = sampleBuff[pos];
|
||||
m_valMid += (m_sample - m_valMid) / 1024.0f;
|
||||
|
||||
++m_sampleNo;
|
||||
|
||||
// Detect Transition
|
||||
// -----------------
|
||||
transition = ! ((m_lastSample < m_valMid) ^ (m_sample >= m_valMid)); // use XOR for speed
|
||||
|
||||
// If this is a transition
|
||||
// -----------------------
|
||||
if (transition)
|
||||
{
|
||||
// Calculate samples since last trans
|
||||
// ----------------------------------
|
||||
int32_t fractional_1024 = (int32_t)(((m_sample - m_valMid)*1024) / (m_sample - m_lastSample));
|
||||
if (fractional_1024 < 0) { fractional_1024 = -fractional_1024; }
|
||||
|
||||
samplePos_1024 = (m_sampleNo<<10)-fractional_1024;
|
||||
len_1024 = samplePos_1024 - m_lastTransPos_1024;
|
||||
m_lastTransPos_1024 = samplePos_1024;
|
||||
|
||||
// If symbol is large enough to be valid
|
||||
// -------------------------------------
|
||||
if (len_1024 > m_minSymSamples_1024)
|
||||
{
|
||||
// Check for shortest good transition
|
||||
// ----------------------------------
|
||||
if ((len_1024 < m_shortestGoodTrans_1024) &&
|
||||
(m_goodTransitions < BAUD_STABLE)) // detect change of symbol size
|
||||
{
|
||||
int32_t fractionOfShortest_1024 = (len_1024<<10) / m_shortestGoodTrans_1024;
|
||||
|
||||
// If currently at half the baud rate
|
||||
// ----------------------------------
|
||||
if ((fractionOfShortest_1024 > 410) && (fractionOfShortest_1024 < 614)) // 0.4 and 0.6
|
||||
{
|
||||
m_averageSymbolLen_1024 /= 2;
|
||||
m_shortestGoodTrans_1024 = len_1024;
|
||||
}
|
||||
// If currently at the wrong baud rate
|
||||
// -----------------------------------
|
||||
else if (fractionOfShortest_1024 < 768) // 0.75
|
||||
{
|
||||
m_averageSymbolLen_1024 = len_1024;
|
||||
m_shortestGoodTrans_1024 = len_1024;
|
||||
m_goodTransitions = 0;
|
||||
m_lastSingleBitPos_1024 = samplePos_1024 - len_1024;
|
||||
}
|
||||
}
|
||||
|
||||
// Calc the number of bits since events
|
||||
// ------------------------------------
|
||||
int32_t halfSymbol_1024 = m_averageSymbolLen_1024 / 2;
|
||||
int bitsSinceLastTrans = max((uint32_t)1, (len_1024+halfSymbol_1024) / m_averageSymbolLen_1024 );
|
||||
int bitsSinceLastSingle = (((m_sampleNo<<10)-m_lastSingleBitPos_1024) + halfSymbol_1024) / m_averageSymbolLen_1024;
|
||||
|
||||
// Check for single bit
|
||||
// --------------------
|
||||
if (bitsSinceLastTrans == 1)
|
||||
{
|
||||
m_lastSingleBitPos_1024 = samplePos_1024;
|
||||
}
|
||||
|
||||
// If too long since last transition
|
||||
// ---------------------------------
|
||||
if (bitsSinceLastTrans > MAX_CONSEC_SAME)
|
||||
{
|
||||
resetVals();
|
||||
}
|
||||
// If too long sice last single bit
|
||||
// --------------------------------
|
||||
else if (bitsSinceLastSingle > MAX_WITHOUT_SINGLE)
|
||||
{
|
||||
resetVals();
|
||||
}
|
||||
else
|
||||
{
|
||||
// If this is a good transition
|
||||
// ----------------------------
|
||||
int32_t offsetFromExtectedTransition_1024 = len_1024 - (bitsSinceLastTrans*m_averageSymbolLen_1024);
|
||||
if (offsetFromExtectedTransition_1024 < 0) { offsetFromExtectedTransition_1024 = -offsetFromExtectedTransition_1024; }
|
||||
if (offsetFromExtectedTransition_1024 < ((int32_t)m_averageSymbolLen_1024 / 4)) // Has to be within 1/4 of symbol to be good
|
||||
{
|
||||
++m_goodTransitions;
|
||||
uint32_t bitsCount = min((uint32_t)BAUD_STABLE, m_goodTransitions);
|
||||
|
||||
uint32_t propFromPrevious = m_averageSymbolLen_1024*bitsCount;
|
||||
uint32_t propFromCurrent = (len_1024 / bitsSinceLastTrans);
|
||||
m_averageSymbolLen_1024 = (propFromPrevious + propFromCurrent) / (bitsCount + 1);
|
||||
m_badTransitions = 0;
|
||||
//if ( len < m_shortestGoodTrans ){m_shortestGoodTrans = len;}
|
||||
// Store the old symbol size
|
||||
if (m_goodTransitions >= BAUD_STABLE)
|
||||
{
|
||||
m_lastStableSymbolLen_1024 = m_averageSymbolLen_1024;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Set the point of the last bit if not yet stable
|
||||
// -----------------------------------------------
|
||||
if ((m_goodTransitions < BAUD_STABLE) || (m_badTransitions > 0))
|
||||
{
|
||||
m_lastBitPos_1024 = samplePos_1024 - (m_averageSymbolLen_1024 / 2);
|
||||
}
|
||||
|
||||
// Calculate the exact positiom of the next bit
|
||||
// --------------------------------------------
|
||||
int32_t thisPlusHalfsymbol_1024 = samplePos_1024 + (m_averageSymbolLen_1024/2);
|
||||
int32_t lastPlusSymbol = m_lastBitPos_1024 + m_averageSymbolLen_1024;
|
||||
m_nextBitPos_1024 = lastPlusSymbol + ((thisPlusHalfsymbol_1024 - lastPlusSymbol) / 16);
|
||||
|
||||
// Check for bad pos error
|
||||
// -----------------------
|
||||
if (m_nextBitPos_1024 < samplePos_1024) m_nextBitPos_1024 += m_averageSymbolLen_1024;
|
||||
|
||||
// Calculate integer sample after next bit
|
||||
// ---------------------------------------
|
||||
m_nextBitPosInt = (m_nextBitPos_1024>>10) + 1;
|
||||
|
||||
} // symbol is large enough to be valid
|
||||
else
|
||||
{
|
||||
// Bad transition, so reset the counts
|
||||
// -----------------------------------
|
||||
++m_badTransitions;
|
||||
if (m_badTransitions > MAX_BAD_TRANS)
|
||||
{
|
||||
resetVals();
|
||||
}
|
||||
}
|
||||
} // end of if transition
|
||||
|
||||
// Reached the point of the next bit
|
||||
// ---------------------------------
|
||||
if (m_sampleNo >= m_nextBitPosInt)
|
||||
{
|
||||
// Everything is good so extract a bit
|
||||
// -----------------------------------
|
||||
if (m_goodTransitions > 20)
|
||||
{
|
||||
// Store value at the center of bit
|
||||
// --------------------------------
|
||||
storeBit();
|
||||
}
|
||||
// Check for long 1 or zero
|
||||
// ------------------------
|
||||
uint32_t bitsSinceLastTrans = ((m_sampleNo<<10) - m_lastTransPos_1024) / m_averageSymbolLen_1024;
|
||||
if (bitsSinceLastTrans > m_maxRunOfSameValue)
|
||||
{
|
||||
resetVals();
|
||||
}
|
||||
|
||||
// Store the point of the last bit
|
||||
// -------------------------------
|
||||
m_lastBitPos_1024 = m_nextBitPos_1024;
|
||||
|
||||
// Calculate the exact point of the next bit
|
||||
// -----------------------------------------
|
||||
m_nextBitPos_1024 += m_averageSymbolLen_1024;
|
||||
|
||||
// Look for the bit after the next bit pos
|
||||
// ---------------------------------------
|
||||
m_nextBitPosInt = (m_nextBitPos_1024>>10) + 1;
|
||||
|
||||
} // Reached the point of the next bit
|
||||
|
||||
m_lastSample = m_sample;
|
||||
|
||||
} // Loop through the block of data
|
||||
|
||||
return getNoOfBits();
|
||||
}
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
void POCSAGProcessor::storeBit()
|
||||
{
|
||||
if (++m_bitsStart >= BIT_BUF_SIZE) { m_bitsStart = 0; }
|
||||
|
||||
// Calculate the bit value
|
||||
float sample = (m_sample + m_lastSample) / 2;
|
||||
//int32_t sample_1024 = m_sample_1024;
|
||||
bool bit = sample > m_valMid;
|
||||
|
||||
// If buffer not full
|
||||
if (m_bitsStart != m_bitsEnd)
|
||||
{
|
||||
// Decide on output val
|
||||
if (bit)
|
||||
{
|
||||
m_bits[m_bitsStart] = 0;
|
||||
}
|
||||
else
|
||||
{
|
||||
m_bits[m_bitsStart] = 1;
|
||||
}
|
||||
}
|
||||
// Throw away bits if the buffer is full
|
||||
else
|
||||
{
|
||||
if (--m_bitsStart <= -1)
|
||||
{
|
||||
m_bitsStart = BIT_BUF_SIZE - 1;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
int POCSAGProcessor::extractFrames()
|
||||
{
|
||||
int msgCnt = 0;
|
||||
// While there is unread data in the bits buffer
|
||||
//----------------------------------------------
|
||||
while (getNoOfBits() > 0)
|
||||
{
|
||||
m_fifo.codeword = (m_fifo.codeword << 1) + getBit();
|
||||
m_fifo.numBits++;
|
||||
|
||||
// If number of bits in fifo equals 32
|
||||
//------------------------------------
|
||||
if (m_fifo.numBits >= 32)
|
||||
{
|
||||
// Not got sync
|
||||
// ------------
|
||||
if (!m_gotSync)
|
||||
{
|
||||
if (bitsDiff(m_fifo.codeword, M_SYNC) <= 2)
|
||||
{
|
||||
m_inverted = false;
|
||||
m_gotSync = true;
|
||||
m_numCode = -1;
|
||||
m_fifo.numBits = 0;
|
||||
}
|
||||
else if (bitsDiff(m_fifo.codeword, M_NOTSYNC) <= 2)
|
||||
{
|
||||
m_inverted = true;
|
||||
m_gotSync = true;
|
||||
m_numCode = -1;
|
||||
m_fifo.numBits = 0;
|
||||
}
|
||||
else
|
||||
{
|
||||
// Cause it to load one more bit
|
||||
m_fifo.numBits = 31;
|
||||
}
|
||||
} // Not got sync
|
||||
else
|
||||
{
|
||||
// Increment the word count
|
||||
// ------------------------
|
||||
++m_numCode; // It got set to -1 when a sync was found, now count the 16 words
|
||||
uint32_t val = m_inverted ? ~m_fifo.codeword : m_fifo.codeword;
|
||||
OnDataWord(val, m_numCode);
|
||||
|
||||
// If at the end of a 16 word block
|
||||
// --------------------------------
|
||||
if (m_numCode >= 15)
|
||||
{
|
||||
msgCnt += OnDataFrame(m_numCode+1, (m_samplesPerSec<<10) / m_lastStableSymbolLen_1024);
|
||||
m_gotSync = false;
|
||||
m_numCode = -1;
|
||||
}
|
||||
m_fifo.numBits = 0;
|
||||
}
|
||||
} // If number of bits in fifo equals 32
|
||||
} // While there is unread data in the bits buffer
|
||||
return msgCnt;
|
||||
} // extractFrames
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
short POCSAGProcessor::getBit()
|
||||
{
|
||||
if (m_bitsEnd != m_bitsStart)
|
||||
{
|
||||
if (++m_bitsEnd >= BIT_BUF_SIZE)
|
||||
{
|
||||
m_bitsEnd = 0;
|
||||
}
|
||||
return m_bits[m_bitsEnd];
|
||||
}
|
||||
else
|
||||
{
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
int POCSAGProcessor::getNoOfBits()
|
||||
{
|
||||
int bits = m_bitsEnd - m_bitsStart;
|
||||
if (bits < 0) { bits += BIT_BUF_SIZE; }
|
||||
return bits;
|
||||
}
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
uint32_t POCSAGProcessor::getRate()
|
||||
{
|
||||
return ((m_samplesPerSec<<10)+512) / m_lastStableSymbolLen_1024;
|
||||
}
|
||||
|
||||
|
||||
// ====================================================================
|
||||
//
|
||||
// ====================================================================
|
||||
int main() {
|
||||
EventDispatcher event_dispatcher { std::make_unique<POCSAGProcessor>() };
|
||||
event_dispatcher.run();
|
||||
|
||||
@@ -40,25 +40,100 @@
|
||||
#include "portapack_shared_memory.hpp"
|
||||
|
||||
#include <cstdint>
|
||||
#include <bitset>
|
||||
using namespace std;
|
||||
|
||||
// Class used to smooth demodulated waveform prior to decoding
|
||||
// -----------------------------------------------------------
|
||||
template <class ValType, class CalcType>
|
||||
class SmoothVals
|
||||
{
|
||||
protected:
|
||||
ValType * m_lastVals; // Previoius N values
|
||||
int m_size; // The size N
|
||||
CalcType m_sumVal; // Running sum of lastVals
|
||||
int m_pos; // Current position in last vals ring buffer
|
||||
int m_count; //
|
||||
|
||||
class POCSAGProcessor : public BasebandProcessor {
|
||||
public:
|
||||
SmoothVals() : m_lastVals(NULL), m_size(1), m_sumVal(0), m_pos(0), m_count(0)
|
||||
{
|
||||
m_lastVals = new ValType[m_size];
|
||||
}
|
||||
|
||||
// --------------------------------------------------
|
||||
// --------------------------------------------------
|
||||
virtual ~SmoothVals()
|
||||
{
|
||||
delete[] m_lastVals;
|
||||
}
|
||||
|
||||
// --------------------------------------------------
|
||||
// Set size of smoothing
|
||||
// --------------------------------------------------
|
||||
void SetSize(int size)
|
||||
{
|
||||
m_size = std::max(size, 1);
|
||||
m_pos = 0;
|
||||
delete[] m_lastVals;
|
||||
m_lastVals = new ValType[m_size];
|
||||
m_sumVal = 0;
|
||||
}
|
||||
|
||||
// --------------------------------------------------
|
||||
// Get size of smoothing
|
||||
// --------------------------------------------------
|
||||
int Size() { return m_size; }
|
||||
|
||||
// --------------------------------------------------
|
||||
// In place processing
|
||||
// --------------------------------------------------
|
||||
void Process(ValType * valBuff, int numVals)
|
||||
{
|
||||
ValType tmpVal;
|
||||
|
||||
if (m_count > (1024*10))
|
||||
{
|
||||
// Recalculate the sum value occasionaly, stops accumulated errors when using float
|
||||
m_count = 0;
|
||||
m_sumVal = 0;
|
||||
for (int i = 0; i < m_size; ++i) { m_sumVal += (CalcType)m_lastVals[i]; }
|
||||
}
|
||||
|
||||
// Use a rolling smoothed value while processing the buffer
|
||||
for (int buffPos = 0; buffPos < numVals; ++buffPos)
|
||||
{
|
||||
m_pos = (m_pos + 1); // Increment the position in the stored values
|
||||
if (m_pos >= m_size) { m_pos = 0; } // loop if reached the end of the stored values
|
||||
|
||||
m_sumVal -= (CalcType)m_lastVals[m_pos]; // Subtract the oldest value
|
||||
m_lastVals[m_pos] = valBuff[buffPos]; // Store the new value
|
||||
m_sumVal += (CalcType)m_lastVals[m_pos]; // Add on the new value
|
||||
|
||||
tmpVal = (ValType)(m_sumVal / m_size); // Scale by number of values smoothed
|
||||
valBuff[buffPos] = tmpVal;
|
||||
}
|
||||
|
||||
m_count += numVals;
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
|
||||
// --------------------------------------------------
|
||||
// Class to process base band data to pocsag frames
|
||||
// --------------------------------------------------
|
||||
class POCSAGProcessor : public BasebandProcessor{
|
||||
public:
|
||||
|
||||
void execute(const buffer_c8_t& buffer) override;
|
||||
|
||||
void on_message(const Message* const message) override;
|
||||
|
||||
private:
|
||||
enum rx_states {
|
||||
WAITING = 0,
|
||||
PREAMBLE = 32,
|
||||
SYNC = 64,
|
||||
//LOSING_SYNC = 65,
|
||||
//LOST_SYNC = 66,
|
||||
//ADDRESS = 67,
|
||||
//MESSAGE = 68,
|
||||
//END_OF_MESSAGE = 69
|
||||
};
|
||||
int OnDataFrame(int len, int baud);
|
||||
int OnDataWord(uint32_t word, int pos);
|
||||
|
||||
private:
|
||||
static constexpr size_t baseband_fs = 3072000;
|
||||
|
||||
BasebandThread baseband_thread { baseband_fs, this, NORMALPRIO + 20, baseband::Direction::Receive };
|
||||
@@ -79,28 +154,71 @@ private:
|
||||
dsp::decimate::FIRC16xR16x32Decim8 decim_1 { };
|
||||
dsp::decimate::FIRAndDecimateComplex channel_filter { };
|
||||
dsp::demodulate::FM demod { };
|
||||
SmoothVals<float, float> smooth;
|
||||
|
||||
//AudioOutput audio_output { };
|
||||
AudioOutput audio_output { };
|
||||
|
||||
uint32_t sync_timeout { 0 };
|
||||
uint32_t msg_timeout { 0 };
|
||||
|
||||
uint32_t slicer_sr { 0 };
|
||||
uint32_t sphase { 0 };
|
||||
uint32_t sphase_delta { 0 };
|
||||
uint32_t sphase_delta_half { 0 };
|
||||
uint32_t sphase_delta_eighth { 0 };
|
||||
uint32_t rx_data { 0 };
|
||||
uint32_t rx_bit { 0 };
|
||||
bool configured = false;
|
||||
rx_states rx_state { WAITING };
|
||||
pocsag::BitRate bitrate { pocsag::BitRate::FSK1200 };
|
||||
bool phase = false ;
|
||||
uint32_t codeword_count { 0 };
|
||||
pocsag::POCSAGPacket packet { };
|
||||
|
||||
void push_packet(pocsag::PacketFlag flag);
|
||||
void configure(const POCSAGConfigureMessage& message);
|
||||
|
||||
void configure();
|
||||
|
||||
// ----------------------------------------
|
||||
// Frame extractraction methods and members
|
||||
// ----------------------------------------
|
||||
private:
|
||||
void initFrameExtraction();
|
||||
struct FIFOStruct {
|
||||
unsigned long codeword;
|
||||
int numBits;
|
||||
};
|
||||
|
||||
#define BIT_BUF_SIZE (64)
|
||||
|
||||
void resetVals();
|
||||
void setFrameExtractParams(long a_samplesPerSec, long a_maxBaud = 8000, long a_minBaud = 200, long maxRunOfSameValue = 32);
|
||||
|
||||
int processDemodulatedSamples(float * sampleBuff, int noOfSamples);
|
||||
int extractFrames();
|
||||
|
||||
void storeBit();
|
||||
short getBit();
|
||||
|
||||
int getNoOfBits();
|
||||
uint32_t getRate();
|
||||
|
||||
uint32_t m_averageSymbolLen_1024{0};
|
||||
uint32_t m_lastStableSymbolLen_1024{0};
|
||||
|
||||
uint32_t m_samplesPerSec{0};
|
||||
uint32_t m_goodTransitions{0};
|
||||
uint32_t m_badTransitions{0};
|
||||
|
||||
uint32_t m_sampleNo{0};
|
||||
float m_sample{0};
|
||||
float m_valMid{0.0f};
|
||||
float m_lastSample{0.0f};
|
||||
|
||||
uint32_t m_lastTransPos_1024{0};
|
||||
uint32_t m_lastSingleBitPos_1024{0};
|
||||
|
||||
uint32_t m_nextBitPosInt{0}; // Integer rounded up version to save on ops
|
||||
uint32_t m_nextBitPos_1024{0};
|
||||
uint32_t m_lastBitPos_1024{0};
|
||||
|
||||
uint32_t m_shortestGoodTrans_1024{0};
|
||||
uint32_t m_minSymSamples_1024{0};
|
||||
uint32_t m_maxSymSamples_1024{0};
|
||||
uint32_t m_maxRunOfSameValue{0};
|
||||
|
||||
bitset<(size_t)BIT_BUF_SIZE> m_bits{0};
|
||||
long m_bitsStart{0};
|
||||
long m_bitsEnd{0};
|
||||
|
||||
FIFOStruct m_fifo{0,0};
|
||||
bool m_gotSync{false};
|
||||
int m_numCode{0};
|
||||
bool m_inverted{false};
|
||||
|
||||
};
|
||||
|
||||
|
||||
Reference in New Issue
Block a user