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Cleaned up quantization average 

Now average is computed over all the syncword symbols, for each syncword
as a simple average.

TG-81
This commit is contained in:
Niccolò Izzo 2022-05-13 12:59:53 +02:00 committed by Silvano Seva
parent 5fe5b0e578
commit ef61c532a3
2 changed files with 17 additions and 39 deletions
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2
openrtx/include/protocols/M17/M17Demodulator.h
View File

@ -220,7 +220,7 @@ private:
* @param offset: index value to be added to the exponential moving * @param offset: index value to be added to the exponential moving
* average/variance computation * average/variance computation
*/ */
void updateQuantizationStats(int32_t offset); void updateQuantizationStats(int32_t frame_index, int32_t symbol_index);
/** /**
* Computes the convolution between a stride of samples starting from * Computes the convolution between a stride of samples starting from

54
openrtx/src/protocols/M17/M17Demodulator.cpp
View File

@ -130,49 +130,27 @@ void M17Demodulator::resetQuantizationStats()
qnt_neg_avg = 0.0f; qnt_neg_avg = 0.0f;
} }
void M17Demodulator::updateQuantizationStats(int32_t offset) void M17Demodulator::updateQuantizationStats(int32_t frame_index,
int32_t symbol_index)
{ {
// If offset is negative use bridge buffer int16_t sample = baseband.data[symbol_index];
int16_t sample = 0;
if (offset < 0) // When we are at negative offsets use bridge buffer
sample = basebandBridge[M17_BRIDGE_SIZE + offset];
else // Otherwise use regular data buffer
sample = baseband.data[offset];
if (sample > 0) if (sample > 0)
{
qnt_pos_fifo.push_front(sample); qnt_pos_fifo.push_front(sample);
// FIFO not full, compute traditional average else
if (qnt_pos_fifo.size() <= QNT_SMA_WINDOW) qnt_neg_fifo.push_front(sample);
{ // If we reached end of the syncword, compute average and reset queue
if(frame_index == M17_SYNCWORD_SYMBOLS - 1)
{
int32_t acc = 0; int32_t acc = 0;
for(auto e : qnt_pos_fifo) for(auto e : qnt_pos_fifo)
acc += e; acc += e;
qnt_pos_avg = acc / static_cast<float>(qnt_pos_fifo.size()); qnt_pos_avg = acc / static_cast<float>(qnt_pos_fifo.size());
} acc = 0;
else
{
qnt_pos_avg += 1 / static_cast<float>(QNT_SMA_WINDOW) *
(sample - qnt_pos_fifo.back());
qnt_pos_fifo.pop_back();
}
}
else
{
qnt_neg_fifo.push_front(sample);
// FIFO not full, compute traditional average
if (qnt_neg_fifo.size() <= QNT_SMA_WINDOW)
{
int32_t acc = 0;
for(auto e : qnt_neg_fifo) for(auto e : qnt_neg_fifo)
acc += e; acc += e;
qnt_neg_avg = acc / static_cast<float>(qnt_neg_fifo.size()); qnt_neg_avg = acc / static_cast<float>(qnt_neg_fifo.size());
} qnt_pos_fifo.clear();
else qnt_neg_fifo.clear();
{
qnt_neg_avg += 1 / static_cast<float>(QNT_SMA_WINDOW) *
(sample - qnt_neg_fifo.back());
qnt_neg_fifo.pop_back();
}
} }
} }
@ -243,9 +221,9 @@ int8_t M17Demodulator::quantize(int32_t offset)
sample = basebandBridge[M17_BRIDGE_SIZE + offset]; sample = basebandBridge[M17_BRIDGE_SIZE + offset];
else // Otherwise use regular data buffer else // Otherwise use regular data buffer
sample = baseband.data[offset]; sample = baseband.data[offset];
if (sample > static_cast< int16_t >(qnt_pos_avg / 2.1)) if (sample > static_cast< int16_t >(qnt_pos_avg / 2.0))
return +3; return +3;
else if (sample < static_cast< int16_t >(qnt_neg_avg / 2.1)) else if (sample < static_cast< int16_t >(qnt_neg_avg / 2.0))
return -3; return -3;
else if (sample > 0) else if (sample > 0)
return +1; return +1;
@ -337,7 +315,7 @@ bool M17Demodulator::update()
+ (M17_SAMPLES_PER_SYMBOL * decoded_syms); + (M17_SAMPLES_PER_SYMBOL * decoded_syms);
// Update quantization stats only on syncwords // Update quantization stats only on syncwords
if (frame_index < M17_SYNCWORD_SYMBOLS) if (frame_index < M17_SYNCWORD_SYMBOLS)
updateQuantizationStats(symbol_index); updateQuantizationStats(frame_index, symbol_index);
int8_t symbol = quantize(symbol_index); int8_t symbol = quantize(symbol_index);
// Log quantization // Log quantization
@ -349,8 +327,8 @@ bool M17Demodulator::update()
demod_log log = { demod_log log = {
baseband.data[symbol_index + i], baseband.data[symbol_index + i],
0,0.0,symbol_index + i, 0,0.0,symbol_index + i,
qnt_pos_avg / 2.1f, qnt_pos_avg / 2.0f,
qnt_neg_avg / 2.1f, qnt_neg_avg / 2.0f,
symbol, symbol,
frame_index}; frame_index};
appendLog(&log); appendLog(&log);