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#include "dvbs2_pll.h"
namespace dvbs2
{
S2PLLBlock::S2PLLBlock(std::shared_ptr<dsp::stream<complex_t>> input, float loop_bw)
: Block(input)
{
float damping = sqrtf(2.0f) / 2.0f;
float denom = (1.0 + 2.0 * damping * loop_bw + loop_bw * loop_bw);
alpha = (4 * damping * loop_bw) / denom;
beta = (4 * loop_bw * loop_bw) / denom;
}
S2PLLBlock::~S2PLLBlock()
{
}
void S2PLLBlock::work()
{
int nsamples = input_stream->read();
if (nsamples <= 0)
{
input_stream->flush();
return;
}
for (int i = 0; i < (frame_slot_count + 1) * 90 + pilot_cnt * 36; i++)
{
tmp_val = input_stream->readBuf[i] * complex_t(cosf(-phase), sinf(-phase));
float error = 0;
if (i >= 90)
{
constellation->demod_soft_lut(tmp_val, nullptr, &error);
output_stream->writeBuf[i] = tmp_val;
}
else
{
if (i < 26) // Use known symbols for SOF
error = (tmp_val * sof.symbols[i].conj()).arg();
else // And also use known Modcod and config to synchronize onto the PLS
error = (tmp_val * pls.symbols[pls_code][i - 26].conj()).arg();
// We're done, convert to proper 45 degs BPSK
output_stream->writeBuf[i] = (i & 1) ? complex_t(-tmp_val.real, tmp_val.imag) : complex_t(tmp_val.imag, tmp_val.real);
}
// Compute new freq and phase.
freq += beta * error;
phase += freq + alpha * error;
// Wrap phase
while (phase > (2 * M_PI))
phase -= 2 * M_PI;
while (phase < (-2 * M_PI))
phase += 2 * M_PI;
// Clamp freq
if (freq > 1.0)
freq = 1.0;
if (freq < -1.0)
freq = -1.0;
}
input_stream->flush();
output_stream->swap(nsamples);
}
}
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