digital: cleaned up Costas loop code by switching over to the gri_control_loop class to handle the inner loop. Had to add it to digital_swig.i to properly wrap the parent functions into Python.

author: Tom Rondeau <trondeau@vt.edu> 2011-08-14 22:32:01 -0400
committer: Tom Rondeau <trondeau@vt.edu> 2011-08-14 22:32:01 -0400
commit: ed564be6c78a3e22b3c98862834192f8b20bc551 (patch)
tree: c566277b3a39699669eb684156d09aedae1925be /gr-digital/lib
parent: 7e47bddafc6b27c623137c6d76f460e608952fcc (diff)
2 files changed, 10 insertions, 300 deletions
diff --git a/gr-digital/lib/digital_costas_loop_cc.cc b/gr-digital/lib/digital_costas_loop_cc.cc
index af9e20ac83..370dc7e5c1 100644
--- a/gr-digital/lib/digital_costas_loop_cc.cc
+++ b/gr-digital/lib/digital_costas_loop_cc.cc
@@ -30,8 +30,6 @@
 #include <gr_sincos.h>
 #include <gr_math.h>
 
-#define M_TWOPI (2*M_PI)
-
 digital_costas_loop_cc_sptr
 digital_make_costas_loop_cc (float loop_bw, int order
 			     ) throw (std::invalid_argument)
@@ -45,15 +43,9 @@ digital_costas_loop_cc::digital_costas_loop_cc (float loop_bw, int order
   : gr_sync_block ("costas_loop_cc",
 		   gr_make_io_signature (1, 1, sizeof (gr_complex)),
 		   gr_make_io_signature2 (1, 2, sizeof (gr_complex), sizeof(float))),
-    d_max_freq(1.0), d_min_freq(-1.0),
+    gri_control_loop(loop_bw, 1.0, -1.0),
     d_order(order), d_phase_detector(NULL)
 {
-  // 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);
-
   // Set up the phase detector to use based on the constellation order
   switch(d_order) {
   case 2:
@@ -72,10 +64,6 @@ digital_costas_loop_cc::digital_costas_loop_cc (float loop_bw, int order
     throw std::invalid_argument("order must be 2, 4, or 8");
     break;
   }
-
-  // Initialize loop values
-  d_freq = 0;
-  d_phase = 0;
 }
 
 float
@@ -119,126 +107,6 @@ digital_costas_loop_cc::phase_detector_2(gr_complex sample) const
   return (sample.real()*sample.imag());
 }
 
-/*******************************************************************
-    SET FUNCTIONS
-*******************************************************************/
-
-void
-digital_costas_loop_cc::set_loop_bandwidth(float bw) 
-{
-  if(bw < 0) {
-    throw std::out_of_range ("digital_costas_loop_cc: invalid bandwidth. Must be >= 0.");
-  }
-  
-  d_loop_bw = bw;
-  update_gains();
-}
-
-void
-digital_costas_loop_cc::set_damping_factor(float df) 
-{
-  if(df < 0 || df > 1.0) {
-    throw std::out_of_range ("digital_costas_loop_cc: invalid damping factor. Must be in [0,1].");
-  }
-  
-  d_damping = df;
-  update_gains();
-}
-
-void
-digital_costas_loop_cc::set_alpha(float alpha)
-{
-  if(alpha < 0 || alpha > 1.0) {
-    throw std::out_of_range ("digital_costas_loop_cc: invalid alpha. Must be in [0,1].");
-  }
-  d_alpha = alpha;
-}
-
-void
-digital_costas_loop_cc::set_beta(float beta)
-{
-  if(beta < 0 || beta > 1.0) {
-    throw std::out_of_range ("digital_costas_loop_cc: invalid beta. Must be in [0,1].");
-  }
-  d_beta = beta;
-}
-
-void
-digital_costas_loop_cc::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
-digital_costas_loop_cc::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;
-}
-
-   
-/*******************************************************************
-    GET FUNCTIONS
-*******************************************************************/
-
-
-float
-digital_costas_loop_cc::get_loop_bandwidth() const
-{
-  return d_loop_bw;
-}
-
-float
-digital_costas_loop_cc::get_damping_factor() const
-{
-  return d_damping;
-}
-
-float
-digital_costas_loop_cc::get_alpha() const
-{
-  return d_alpha;
-}
-
-float
-digital_costas_loop_cc::get_beta() const
-{
-  return d_beta;
-}
-
-float
-digital_costas_loop_cc::get_frequency() const
-{
-  return d_freq;
-}
-
-float
-digital_costas_loop_cc::get_phase() const
-{
-  return d_phase;
-}
-
-
-/*******************************************************************
-*******************************************************************/
-
-
-void
-digital_costas_loop_cc::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;
-}
-
 int
 digital_costas_loop_cc::work (int noutput_items,
 			      gr_vector_const_void_star &input_items,
@@ -262,18 +130,9 @@ digital_costas_loop_cc::work (int noutput_items,
       error = (*this.*d_phase_detector)(optr[i]);
       error = gr_branchless_clip(error, 1.0);
 	
-      d_freq = d_freq + d_beta * error;
-      d_phase = d_phase + d_freq + d_alpha * error;
-
-      while(d_phase>M_TWOPI)
-	d_phase -= M_TWOPI;
-      while(d_phase<-M_TWOPI)
-	d_phase += M_TWOPI;
-
-      if (d_freq > d_max_freq)
-	d_freq = d_min_freq;
-      else if (d_freq < d_min_freq)
-	d_freq = d_max_freq;
+      advance_loop(error);
+      phase_wrap();
+      frequency_limit();
       
       foptr[i] = d_freq;
     } 
@@ -284,20 +143,10 @@ digital_costas_loop_cc::work (int noutput_items,
       
       error = (*this.*d_phase_detector)(optr[i]);
       error = gr_branchless_clip(error, 1.0);
-      
-      d_freq = d_freq + d_beta * error;
-      d_phase = d_phase + d_freq + d_alpha * error;
-      
-      while(d_phase>M_TWOPI)
-	d_phase -= M_TWOPI;
-      while(d_phase<-M_TWOPI)
-	d_phase += M_TWOPI;
-      
-      if (d_freq > d_max_freq)
-	d_freq = d_min_freq;
-      else if (d_freq < d_min_freq)
-	d_freq = d_max_freq;
-      
+
+      advance_loop(error);
+      phase_wrap();
+      frequency_limit();
     }
   }
   return noutput_items;
diff --git a/gr-digital/lib/digital_costas_loop_cc.h b/gr-digital/lib/digital_costas_loop_cc.h
index 83edded194..7b2cd6dad7 100644
--- a/gr-digital/lib/digital_costas_loop_cc.h
+++ b/gr-digital/lib/digital_costas_loop_cc.h
@@ -25,6 +25,7 @@
 #define INCLUDED_DIGITAL_COSTAS_LOOP_CC_H
 
 #include <gr_sync_block.h>
+#include <gri_control_loop.h>
 #include <stdexcept>
 #include <fstream>
 
@@ -72,36 +73,17 @@ digital_make_costas_loop_cc (float loop_bw, int order
  *
  * \p order must be 2 or 4.
  */
-class digital_costas_loop_cc : public gr_sync_block
+class digital_costas_loop_cc : public gr_sync_block, public gri_control_loop
 {
   friend digital_costas_loop_cc_sptr
   digital_make_costas_loop_cc (float loop_bw, int order
 			       ) throw (std::invalid_argument);
 
-  float d_max_freq;
-  float d_min_freq;
   int d_order;
 
-  float d_loop_bw;
-  float d_damping;
-  float d_alpha;
-  float d_beta;
-
-  float d_phase;
-  float d_freq;
-
   digital_costas_loop_cc (float loop_bw, int order
 			  ) throw (std::invalid_argument);
   
-  /*! \brief update the system gains from the loop bandwidth and damping factor
-   *
-   *  This function updates the system gains based on the loop
-   *  bandwidth and damping factor of the system.
-   *  These two factors can be set separately through their own
-   *  set functions.
-   */
-  void update_gains();
-
   /*! \brief the phase detector circuit for 8th-order PSK loops
    *  \param sample complex sample
    *  \return the phase error
@@ -125,127 +107,6 @@ class digital_costas_loop_cc : public gr_sync_block
 
 public:
 
-  /*******************************************************************
-    SET FUNCTIONS
-  *******************************************************************/
-  
-  /*!
-   * \brief Set the loop bandwidth
-   *
-   * Set the loop filter's bandwidth to \p bw. This should be between 
-   * 2*pi/200 and 2*pi/100  (in rads/samp). It must also be a positive
-   * number.
-   *
-   * When a new damping factor is set, the gains, alpha and beta, of the loop
-   * are recalculated by a call to update_gains().
-   *
-   * \param bw    (float) new bandwidth
-   *
-   */
-  void set_loop_bandwidth(float bw);
-
-  /*!
-   * \brief Set the loop damping factor
-   *
-   * Set the loop filter's damping factor to \p df. The damping factor
-   * should be sqrt(2)/2.0 for critically damped systems.
-   * Set it to anything else only if you know what you are doing. It must
-   * be a number between 0 and 1.
-   *
-   * When a new damping factor is set, the gains, alpha and beta, of the loop
-   * are recalculated by a call to update_gains().
-   *
-   * \param df    (float) new damping factor
-   *
-   */
-  void set_damping_factor(float df);
-
-  /*!
-   * \brief Set the loop gain alpha
-   *
-   * Set's the loop filter's alpha gain parameter.
-   *
-   * This value should really only be set by adjusting the loop bandwidth
-   * and damping factor.
-   *
-   * \param alpha    (float) new alpha gain
-   *
-   */
-  void set_alpha(float alpha);
-
-  /*!
-   * \brief Set the loop gain beta
-   *
-   * Set's the loop filter's beta gain parameter.
-   *
-   * This value should really only be set by adjusting the loop bandwidth
-   * and damping factor.
-   *
-   * \param beta    (float) new beta gain
-   *
-   */
-  void set_beta(float beta);
-
-  /*!
-   * \brief Set the Costas loop's frequency.
-   *
-   * Set's the Costas Loop's frequency. While this is normally updated by the
-   * inner loop of the algorithm, it could be useful to manually initialize,
-   * set, or reset this under certain circumstances.
-   *
-   * \param freq    (float) new frequency
-   *
-   */
-  void set_frequency(float freq);
-
-  /*!
-   * \brief Set the Costas loop's phase.
-   *
-   * Set's the Costas Loop's phase. While this is normally updated by the
-   * inner loop of the algorithm, it could be useful to manually initialize,
-   * set, or reset this under certain circumstances.
-   *
-   * \param phase    (float) new phase
-   *
-   */
-  void set_phase(float phase);
-
-
-  /*******************************************************************
-    GET FUNCTIONS
-  *******************************************************************/
-
-  /*!
-   * \brief Returns the loop bandwidth
-   */
-  float get_loop_bandwidth() const;
-
-  /*!
-   * \brief Returns the loop damping factor
-   */
-  float get_damping_factor() const;
-
-  /*!
-   * \brief Returns the loop gain alpha
-   */
-  float get_alpha() const;
-
-  /*!
-   * \brief Returns the loop gain beta
-   */
-  float get_beta() const;
-
-  /*!
-   * \brief Get the Costas loop's frequency estimate
-   */
-  float get_frequency() const;
-
-  /*!
-   * \brief Get the Costas loop's phase estimate
-   */
-  float get_phase() const;
-
-  
   int work (int noutput_items,
 	    gr_vector_const_void_star &input_items,
 	    gr_vector_void_star &output_items);
author	Tom Rondeau <trondeau@vt.edu>	2011-08-14 22:32:01 -0400
committer	Tom Rondeau <trondeau@vt.edu>	2011-08-14 22:32:01 -0400
commit	ed564be6c78a3e22b3c98862834192f8b20bc551 (patch)
tree	c566277b3a39699669eb684156d09aedae1925be /gr-digital/lib
parent	7e47bddafc6b27c623137c6d76f460e608952fcc (diff)