unwrap.cpp

Digital filter designer s handbook C++ code source

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//
//  File = unwrap.cpp
//
//

#include <math.h>
#include <stdlib.h>
#include "unwrap.h"
#include "d_cmplx.h"
#include "cmpxpoly.h" 

extern ofstream DebugFile;

//========================================
//
void UnwrapPhase( int ix, double *phase)
{
  static double half_circle_offset;
  static double old_phase;

  if(ix ==0)
    {
    half_circle_offset = 0.0;
    old_phase = *phase;
    }
  else
    {
    *phase = *phase + half_circle_offset;
    if( fabs(old_phase - *phase) > double(90.0))
      {
      if(old_phase < *phase)
        {
        *phase = *phase - 360.0;
        half_circle_offset -= 360.0;
        }
      else
        {
        *phase = *phase + 360.0;
        half_circle_offset += 360.0;
        }
      }
    old_phase = *phase;
    }
  return;
}