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making the resampler faster

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This commit is contained in:
Carles Fernandez
2015-05-06 10:53:27 +02:00
parent 454d0c0208
commit cace34dffb
1 changed files with 7 additions and 1 deletions
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8
src/algorithms/libs/gnss_signal_processing.cc
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@@ -35,6 +35,8 @@
#include <gnuradio/fxpt_nco.h>
auto auxCeil2 = [](float x){ return static_cast<int>(static_cast<long>((x)+1)); };
void complex_exp_gen(std::complex<float>* _dest, double _f, double _fs, unsigned int _samps)
{
gr::fxpt_nco d_nco;
@@ -158,6 +160,7 @@ void resampler(std::complex<float>* _from, std::complex<float>* _dest, float _fs
float _fs_out, unsigned int _length_in, unsigned int _length_out)
{
unsigned int _codeValueIndex;
float aux;
//--- Find time constants --------------------------------------------------
const float _t_in = 1 / _fs_in; // Incoming sampling period in sec
const float _t_out = 1 / _fs_out; // Out sampling period in sec
@@ -165,7 +168,10 @@ void resampler(std::complex<float>* _from, std::complex<float>* _dest, float _fs
{
//=== Digitizing =======================================================
//--- compute index array to read sampled values -------------------------
_codeValueIndex = ceil((_t_out * ((float)i + 1)) / _t_in) - 1;
//_codeValueIndex = ceil((_t_out * ((float)i + 1)) / _t_in) - 1;
aux = (_t_out * (i + 1)) / _t_in;
_codeValueIndex = auxCeil2(aux) - 1;
//if repeat the chip -> upsample by nearest neighborhood interpolation
_dest[i] = _from[_codeValueIndex];
}