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Faster local carrier generation

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This commit is contained in:
Carles Fernandez 2015-05-05 16:14:46 +02:00
parent b4cfef1a44
commit 90ae04ee19
2 changed files with 61 additions and 27 deletions
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33
src/algorithms/libs/gnss_signal_processing.cc
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@ -32,43 +32,24 @@
*/
#include "gnss_signal_processing.h"
#include <gnuradio/fxpt.h> // fixed point sine and cosine
#include <gnuradio/fxpt_nco.h>
void complex_exp_gen(std::complex<float>* _dest, double _f, double _fs, unsigned int _samps)
{
int phase_i = 0;
int phase_step_i;
float phase_step_f = (float)((GPS_TWO_PI * _f) / _fs);
phase_step_i = gr::fxpt::float_to_fixed(phase_step_f);
float sin_f, cos_f;
for(unsigned int i = 0; i < _samps; i++)
{
gr::fxpt::sincos(phase_i, &sin_f, &cos_f);
_dest[i] = std::complex<float>(cos_f, sin_f);
phase_i += phase_step_i;
}
gr::fxpt_nco d_nco;
d_nco.set_freq(-(GPS_TWO_PI * _f) / _fs);
d_nco.sincos(_dest, _samps, 1);
}
void complex_exp_gen_conj(std::complex<float>* _dest, double _f, double _fs, unsigned int _samps)
{
int phase_i = 0;
int phase_step_i;
float phase_step_f = (float)((GPS_TWO_PI * _f) / _fs);
phase_step_i = gr::fxpt::float_to_fixed(phase_step_f);
float sin_f, cos_f;
for(unsigned int i = 0; i < _samps; i++)
{
gr::fxpt::sincos(phase_i, &sin_f, &cos_f);
_dest[i] = std::complex<float>(cos_f, -sin_f);
phase_i += phase_step_i;
}
gr::fxpt_nco d_nco;
d_nco.set_freq(-(GPS_TWO_PI * _f) / _fs);
d_nco.sincos(_dest, _samps, 1);
}
void hex_to_binary_converter(int * _dest, char _from)
{
switch(_from)

55
src/tests/arithmetic/code_generation_test.cc
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@ -33,6 +33,7 @@
#include <complex>
#include <ctime>
#include "gps_sdr_signal_processing.h"
#include "gnss_signal_processing.h"
@ -42,7 +43,7 @@ TEST(CodeGenGPSL1_Test, CodeGeneration)
signed int _prn = 1;
unsigned int _chip_shift = 4;
int iterations = 100;
int iterations = 100000;
struct timeval tv;
gettimeofday(&tv, NULL);
@ -128,3 +129,55 @@ TEST(CodeGenGPSL1Sampled_Test, CodeGeneration)
}
delete[] _dest2; */
}
TEST(ComplexCarrier_Test, CodeGeneration)
{
//signed int _prn = 1;
//unsigned int _chip_shift = 4;
double _fs = 8000000;
double _f = 4000;
const signed int _codeFreqBasis = 1023000; //Hz
const signed int _codeLength = 1023;
int _samplesPerCode = round(_fs / (_codeFreqBasis / _codeLength));
std::complex<float>* _dest = new std::complex<float>[_samplesPerCode];
int iterations = 100000;
struct timeval tv;
gettimeofday(&tv, NULL);
long long int begin = tv.tv_sec * 1000000 + tv.tv_usec;
for(int i = 0; i < iterations; i++)
{
//gps_l1_ca_code_gen_complex_sampled( _dest, _prn, _fs, _chip_shift);
complex_exp_gen_conj( _dest, _f, _fs, _samplesPerCode);
}
gettimeofday(&tv, NULL);
long long int end = tv.tv_sec * 1000000 + tv.tv_usec;
ASSERT_LE(0, end - begin);
std::cout << "Carrier generation completed in " << (end - begin) << " microseconds" << std::endl;
/* std::complex<float>* _dest2 = new std::complex<float>[_samplesPerCode];
gettimeofday(&tv, NULL);
long long int begin2 = tv.tv_sec * 1000000 + tv.tv_usec;
for(int i = 0; i < iterations; i++)
{
complex_exp_gen_conj2( _dest2, _f, _fs, _samplesPerCode);
}
gettimeofday(&tv, NULL);
long long int end2 = tv.tv_sec * 1000000 + tv.tv_usec;
std::cout << "Carrier generation completed in " << (end2 - begin2) << " microseconds (New)" << std::endl;
for (int j=0; j<_samplesPerCode;j++)
{
if(std::abs(_dest[j] - _dest2[j]) > 0.1) std::cout << "Error!" << std::endl;
}
std::cout << _dest[10] << "and " << _dest2[10] << std::endl;
delete[] _dest2;*/
delete[] _dest;
}