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/* -*- c++ -*- */
/*
* Copyright 2011,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <blocks/control_loop.h>
#include <gr_math.h>
#include <stdexcept>
namespace gr {
namespace blocks {
#define M_TWOPI (2.0f*M_PI)
control_loop::control_loop(float loop_bw,
float max_freq, float min_freq)
: d_phase(0), d_freq(0), d_max_freq(max_freq), d_min_freq(min_freq)
{
// Set the damping factor for a critically damped system
d_damping = sqrtf(2.0f)/2.0f;
// Set the bandwidth, which will then call update_gains()
set_loop_bandwidth(loop_bw);
}
control_loop::~control_loop()
{
}
void
control_loop::update_gains()
{
float denom = (1.0 + 2.0*d_damping*d_loop_bw + d_loop_bw*d_loop_bw);
d_alpha = (4*d_damping*d_loop_bw) / denom;
d_beta = (4*d_loop_bw*d_loop_bw) / denom;
}
void
control_loop::advance_loop(float error)
{
d_freq = d_freq + d_beta * error;
d_phase = d_phase + d_freq + d_alpha * error;
}
void
control_loop::phase_wrap()
{
while(d_phase>M_TWOPI)
d_phase -= M_TWOPI;
while(d_phase<-M_TWOPI)
d_phase += M_TWOPI;
}
void
control_loop::frequency_limit()
{
if(d_freq > d_max_freq)
d_freq = d_max_freq;
else if(d_freq < d_min_freq)
d_freq = d_min_freq;
}
/*******************************************************************
* SET FUNCTIONS
*******************************************************************/
void
control_loop::set_loop_bandwidth(float bw)
{
if(bw < 0) {
throw std::out_of_range ("control_loop: invalid bandwidth. Must be >= 0.");
}
d_loop_bw = bw;
update_gains();
}
void
control_loop::set_damping_factor(float df)
{
if(df < 0 || df > 1.0) {
throw std::out_of_range ("control_loop: invalid damping factor. Must be in [0,1].");
}
d_damping = df;
update_gains();
}
void
control_loop::set_alpha(float alpha)
{
if(alpha < 0 || alpha > 1.0) {
throw std::out_of_range ("control_loop: invalid alpha. Must be in [0,1].");
}
d_alpha = alpha;
}
void
control_loop::set_beta(float beta)
{
if(beta < 0 || beta > 1.0) {
throw std::out_of_range ("control_loop: invalid beta. Must be in [0,1].");
}
d_beta = beta;
}
void
control_loop::set_frequency(float freq)
{
if(freq > d_max_freq)
d_freq = d_min_freq;
else if(freq < d_min_freq)
d_freq = d_max_freq;
else
d_freq = freq;
}
void
control_loop::set_phase(float phase)
{
d_phase = phase;
while(d_phase>M_TWOPI)
d_phase -= M_TWOPI;
while(d_phase<-M_TWOPI)
d_phase += M_TWOPI;
}
void
control_loop::set_max_freq(float freq)
{
d_max_freq = freq;
}
void
control_loop::set_min_freq(float freq)
{
d_min_freq = freq;
}
/*******************************************************************
* GET FUNCTIONS
*******************************************************************/
float
control_loop::get_loop_bandwidth() const
{
return d_loop_bw;
}
float
control_loop::get_damping_factor() const
{
return d_damping;
}
float
control_loop::get_alpha() const
{
return d_alpha;
}
float
control_loop::get_beta() const
{
return d_beta;
}
float
control_loop::get_frequency() const
{
return d_freq;
}
float
control_loop::get_phase() const
{
return d_phase;
}
float
control_loop::get_max_freq() const
{
return d_max_freq;
}
float
control_loop::get_min_freq() const
{
return d_min_freq;
}
} /* namespace blocks */
} /* namespace gr */
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