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Implementation of Differential Arctangent Discriminator for FLL

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This commit is contained in:
Javier Arribas
2019-05-15 17:38:45 +02:00
parent 93bea1591b
commit be5ffe6b67
4 changed files with 51 additions and 3 deletions
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32
src/algorithms/tracking/libs/tracking_discriminators.cc
View File

@@ -33,10 +33,26 @@
*/
#include "tracking_discriminators.h"
#include "MATH_CONSTANTS.h"
#include <cmath>
// All the outputs are in RADIANS
double phase_unwrap(double phase_rad)
{
if (phase_rad >= HALF_PI)
{
return phase_rad - PI;
}
else if (phase_rad <= -HALF_PI)
{
return phase_rad + PI;
}
else
{
return phase_rad;
}
}
/*
* FLL four quadrant arctan discriminator:
* \f{equation}
@@ -54,6 +70,22 @@ double fll_four_quadrant_atan(gr_complex prompt_s1, gr_complex prompt_s2, double
return atan2(cross, dot) / (t2 - t1);
}
/*
* FLL differential arctan discriminator:
* \f{equation}
* e_{atan}(k)=\frac{1}{t_1-t_2}\text{phase_unwrap}(\tan^-1(\frac{Q(k)}{I(k)})-\tan^-1(\frac{Q(k-1)}{I(k-1)}))
* \f}
* The output is in [radians/second].
*/
double fll_diff_atan(gr_complex prompt_s1, gr_complex prompt_s2, double t1, double t2)
{
double diff_atan = atan(prompt_s2.imag() / prompt_s2.real()) - atan(prompt_s1.imag() / prompt_s1.real());
if (std::isnan(diff_atan))
{
diff_atan = 0;
}
return phase_unwrap(diff_atan) / (t2 - t1);
}
/*
* PLL four quadrant arctan discriminator:

13
src/algorithms/tracking/libs/tracking_discriminators.h
View File

@@ -52,6 +52,19 @@
*/
double fll_four_quadrant_atan(gr_complex prompt_s1, gr_complex prompt_s2, double t1, double t2);
/*
* FLL differential arctan discriminator:
* \f{equation}
* e_{atan}(k)=\frac{1}{t_1-t_2}\text{phase_unwrap}(\tan^-1(\frac{Q(k)}{I(k)})-\tan^-1(\frac{Q(k-1)}{I(k-1)}))
* \f}
* The output is in [radians/second].
*/
double fll_diff_atan(gr_complex prompt_s1, gr_complex prompt_s2, double t1, double t2);
/*! \brief Phase unwrapping function, input is [rad]
*
*/
double phase_unwrap(double phase_rad);
/*! \brief PLL four quadrant arctan discriminator
*