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Use new decimation filters in AIS processor.

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This commit is contained in:
Jared Boone 2016-01-01 13:20:02 -08:00
parent 316d5d433b
commit ff05833b02
3 changed files with 32 additions and 22 deletions
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16
firmware/baseband/proc_ais.cpp
View File

@ -26,10 +26,24 @@
#include "i2s.hpp"
using namespace lpc43xx;
#include "dsp_fir_taps.hpp"
AISProcessor::AISProcessor() {
decim_0.configure(taps_11k0_decim_0.taps, 33554432);
decim_1.configure(taps_11k0_decim_1.taps, 131072);
}
void AISProcessor::execute(const buffer_c8_t& buffer) {
/* 2.4576MHz, 2048 samples */
auto decimator_out = decimator.execute(buffer);
const buffer_c16_t dst_buffer {
dst.data(),
dst.size()
};
const auto decim_0_out = decim_0.execute(buffer, dst_buffer);
const auto decim_1_out = decim_1.execute(decim_0_out, dst_buffer);
const auto decimator_out = decim_1_out;
/* 76.8kHz, 64 samples */
feed_channel_stats(decimator_out);

8
firmware/baseband/proc_ais.hpp
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@ -42,11 +42,15 @@
class AISProcessor : public BasebandProcessor {
public:
AISProcessor();
void execute(const buffer_c8_t& buffer) override;
private:
ChannelDecimator decimator { ChannelDecimator::DecimationFactor::By32 };
dsp::matched_filter::MatchedFilter mf { baseband::ais::rrc_taps_76k8_4t_p, 4 };
std::array<complex16_t, 512> dst;
dsp::decimate::FIRC8xR16x24FS4Decim8 decim_0;
dsp::decimate::FIRC16xR16x32Decim8 decim_1;
dsp::matched_filter::MatchedFilter mf { baseband::ais::rrc_taps_38k4_4t_p, 2 };
clock_recovery::ClockRecovery<clock_recovery::FixedErrorFilter> clock_recovery {
19200, 9600, { 0.0555f },

30
firmware/common/ais_baseband.hpp
View File

@ -36,25 +36,17 @@ namespace ais {
// cleaning up ISI.
// Translate+RRC filter
// sample=76.8k, deviation=2400, b=0.5, symbol=9600
// Length: 32 taps, 4 symbols, 1 cycle of sinusoid
constexpr std::array<std::complex<float>, 32> rrc_taps_76k8_4t_p { {
{ 5.3368736990e-03f, 0.0000000000e+00f }, { 4.6850211151e-03f, 9.3190864122e-04f },
{ 1.7970187432e-03f, 7.4434953528e-04f }, { -2.5478608559e-03f, -1.7024261963e-03f },
{ -6.6710920858e-03f, -6.6710920858e-03f }, { -8.6960320791e-03f, -1.3014531722e-02f },
{ -7.5474785839e-03f, -1.8221225159e-02f }, { -3.8115552023e-03f, -1.9161981995e-02f },
{ -8.1697309033e-19f, -1.3342183083e-02f }, { 3.6940784220e-05f, -1.8571386338e-04f },
{ -7.5474785839e-03f, 1.8221225159e-02f }, { -2.4954265902e-02f, 3.7346698152e-02f },
{ -5.1450054092e-02f, 5.1450054092e-02f }, { -8.3018814119e-02f, 5.5471398140e-02f },
{ -1.1321218147e-01f, 4.6894020990e-02f }, { -1.3498960022e-01f, 2.6851100952e-02f },
{ -1.4292666316e-01f, 1.7503468055e-17f }, { -1.3498960022e-01f, -2.6851100952e-02f },
{ -1.1321218147e-01f, -4.6894020990e-02f }, { -8.3018814119e-02f, -5.5471398140e-02f },
{ -5.1450054092e-02f, -5.1450054092e-02f }, { -2.4954265902e-02f, -3.7346698152e-02f },
{ -7.5474785839e-03f, -1.8221225159e-02f }, { 3.6940784220e-05f, 1.8571386338e-04f },
{ 2.4509192710e-18f, 1.3342183083e-02f }, { -3.8115552023e-03f, 1.9161981995e-02f },
{ -7.5474785839e-03f, 1.8221225159e-02f }, { -8.6960320791e-03f, 1.3014531722e-02f },
{ -6.6710920858e-03f, 6.6710920858e-03f }, { -2.5478608559e-03f, 1.7024261963e-03f },
{ 1.7970187432e-03f, -7.4434953528e-04f }, { 4.6850211151e-03f, -9.3190864122e-04f },
// sample=38.4k, deviation=2400, b=0.5, symbol=9600
// Length: 16 taps, 4 symbols, 1 cycles of sinusoid
constexpr std::array<std::complex<float>, 16> rrc_taps_38k4_4t_p { {
{ 1.0619794019e-02f, 0.0000000000e+00f }, { 3.5758705854e-03f, 1.4811740938e-03f },
{ -1.3274742629e-02f, -1.3274742629e-02f }, { -1.5018657262e-02f, -3.6258246051e-02f },
{ 0.0000000000e+00f, -2.6549484581e-02f }, { -1.5018657262e-02f, 3.6258246051e-02f },
{ -1.0237997393e-01f, 1.0237997393e-01f }, { -2.2527985355e-01f, 9.3313970669e-02f },
{ -2.8440842032e-01f, 0.0000000000e+00f }, { -2.2527985355e-01f, -9.3313970669e-02f },
{ -1.0237997393e-01f, -1.0237997393e-01f }, { -1.5018657262e-02f, -3.6258246051e-02f },
{ 0.0000000000e+00f, 2.6549484581e-02f }, { -1.5018657262e-02f, 3.6258246051e-02f },
{ -1.3274742629e-02f, 1.3274742629e-02f }, { 3.5758705854e-03f, -1.4811740938e-03f },
} };
} /* namespace ais */