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authorPiotr Krysik <ptrkrysik@gmail.com>2017-01-23 21:53:48 +0100
committerPiotr Krysik <ptrkrysik@gmail.com>2017-01-23 21:53:48 +0100
commit654d652a730e579a770f9a9381c4da13659f6ff6 (patch)
treedc4021d70005eeccd29066329bac4ae3859aa714 /lib
parent93ba6bc2c24eef808fafa41233102e59e56ff1d8 (diff)
Ressurected old frequency correction function
Diffstat (limited to 'lib')
-rw-r--r--lib/receiver/receiver_impl.cc38
-rw-r--r--lib/receiver/receiver_impl.h2
2 files changed, 7 insertions, 33 deletions
diff --git a/lib/receiver/receiver_impl.cc b/lib/receiver/receiver_impl.cc
index f43f6e0..e69183f 100644
--- a/lib/receiver/receiver_impl.cc
+++ b/lib/receiver/receiver_impl.cc
@@ -26,7 +26,6 @@
#include <gnuradio/io_signature.h>
#include <gnuradio/math.h>
-#include <volk/volk.h>
#include <math.h>
#include <boost/circular_buffer.hpp>
#include <algorithm>
@@ -35,7 +34,6 @@
#include <viterbi_detector.h>
#include <string.h>
#include <iostream>
-#include <time.h> //!!!
//#include <iomanip>
#include <boost/scoped_ptr.hpp>
@@ -534,44 +532,22 @@ bool receiver_impl::find_fcch_burst(const gr_complex *input, const int nitems, d
return result;
}
-double receiver_impl::estim_freq_norm(const gr_complex * input, unsigned first_sample, unsigned last_sample) //another frequency estimator
+double receiver_impl::compute_freq_offset(const gr_complex * input, unsigned first_sample, unsigned last_sample)
{
-
+ double phase_sum = 0;
unsigned ii;
- double sum = 0;
-
- for (ii = first_sample; ii < last_sample-1; ii++)
+ for (ii = first_sample; ii < last_sample; ii++)
{
- sum += fast_atan2f(input[ii+1] * conj(input[ii]));
+ double phase_diff = compute_phase_diff(input[ii], input[ii-1]) - (M_PI / 2) / d_OSR;
+ phase_sum += phase_diff;
}
- int N = last_sample-1-first_sample;
- return sum/(2*M_PI)/N * d_OSR;
-}
-double receiver_impl::compute_freq_offset(const gr_complex * input, unsigned first_sample, unsigned last_sample)
-{
- float freq_norm = estim_freq_norm(input, first_sample, last_sample);
- float freq_offset = (freq_norm - 0.25) * 1625000.0/6.0;
+ double phase_offset = phase_sum / (last_sample - first_sample);
+ double freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);
return freq_offset;
}
-//double receiver_impl::compute_freq_offset(const gr_complex * input, unsigned first_sample, unsigned last_sample)
-//{
-// double phase_sum = 0;
-// unsigned ii;
-
-// for (ii = first_sample; ii < last_sample; ii++)
-// {
-// double phase_diff = compute_phase_diff(input[ii], input[ii-1]) - (M_PI / 2) / d_OSR;
-// phase_sum += phase_diff;
-// }
-
-// double phase_offset = phase_sum / (last_sample - first_sample);
-// double freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);
-// return freq_offset;
-//}
-
inline float receiver_impl::compute_phase_diff(gr_complex val1, gr_complex val2)
{
gr_complex conjprod = val1 * conj(val2);
diff --git a/lib/receiver/receiver_impl.h b/lib/receiver/receiver_impl.h
index 251cf55..6074dd5 100644
--- a/lib/receiver/receiver_impl.h
+++ b/lib/receiver/receiver_impl.h
@@ -108,8 +108,6 @@ namespace gr {
* @return true if frequency offset was faound
*/
double compute_freq_offset(const gr_complex * input, unsigned first_sample, unsigned last_sample);
-
- double estim_freq_norm(const gr_complex * input, unsigned first_sample, unsigned last_sample); //normalized frequency estimator
/** Computes angle between two complex numbers
*
* @param val1 first complex number