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dit_nipo_T.cpp
资源名称：simulation_wireless_c++.rar　[点击查看]
上传用户：jtjnyq9001
上传日期：2014-11-21
资源大小：3974k
文件大小：3k
源码类别：

3G开发

开发平台：

Visual C++

dit_nipo_T.cpp：源码内容
  1. //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  2. //
  3. //  File = dit_nipo_T.cpp
  4. //
  5. //  Decimation-In-Time FFT
  6. //
  7. //  Naturally-ordered Input / Scrambled Output   
  8. //
  10. #include <math.h>
  11. #include <complex>
  12. #include "log2.h"
  13. #include "bitrev.h"
  14. #include "misdefs.h"
  15. #include "dit_nipo_T.h"
  16. using namespace std;
  18. template <class T>
  19. void IfftDitNipo( std::complex<T> *array,
  20.                  int fft_size)
  21. {
  22. double trig_arg;
  23. int log2_size;
  24. std::complex<T> twiddle;
  25. std::complex<T> temp;
  26. int pts_in_lft_grp, pts_in_rgt_grp;
  27. int stage, grp_pos, grp_cntr;
  28. int top_node, bot_node;
  30. log2_size = ilog2(fft_size); 
  32. pts_in_rgt_grp = fft_size;
  33. for( stage=1; stage <=log2_size; stage++)
  34.   {   
  35.    grp_cntr = -1;
  36.    
  37.    pts_in_lft_grp = pts_in_rgt_grp;  // set pts_in_left_dft = N/(2**(stage-1))
  38.    pts_in_rgt_grp /= 2;               // set pts_in_right_dft = N/(2**stage)
  40.    for( grp_pos =0; grp_pos < fft_size; grp_pos += pts_in_lft_grp)
  41.      {
  42.       grp_cntr++;
  43.                 
  44.       trig_arg = (TWO_PI*bitrev(grp_cntr, log2_size-1))/fft_size;
  45.       twiddle = std::complex<T>(float(cos(trig_arg)), float(sin(trig_arg)));
  46.                                   
  47.       for( top_node = grp_pos; top_node < grp_pos+pts_in_rgt_grp; 
  48.                                top_node++)
  49.         {                              
  50.          bot_node = top_node + pts_in_rgt_grp;
  51.          temp = array[bot_node] * twiddle;
  52.          array[bot_node] = array[top_node] - temp;
  53.          array[top_node] += temp;
  54.         }  // end of loop over top_node
  55.         
  56.      } // end of loop over grp_pos
  57.   } // end of loop over stage
  58. return;
  59. }
  60. //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
  61. template <class T>
  62. void FftDitNipo( complex<T> *array,
  63.                  int fft_size)
  64. {
  65.    double trig_arg;
  66.    std::complex<T> twiddle, temp;
  67.    int pts_in_lft_grp, pts_in_rgt_grp;
  68.    int stage, grp_pos, grp_cntr;
  69.    int log2_size, top_node, bot_node;
  71.    log2_size = ilog2(fft_size); 
  72.    pts_in_rgt_grp = fft_size;
  73.    for( stage=1; stage <=log2_size; stage++){   
  74.       grp_cntr = -1;
  76.       // set pts_in_left_dft = N/(2**(stage-1))
  77.       pts_in_lft_grp = pts_in_rgt_grp;  
  78.       
  79.       // set pts_in_right_dft = N/(2**stage)
  80.       pts_in_rgt_grp /= 2;
  82.       for(  grp_pos =0; 
  83.             grp_pos < fft_size; 
  84.             grp_pos += pts_in_lft_grp){
  85.          grp_cntr++;
  87.          trig_arg = (TWO_PI * bitrev(grp_cntr, 
  88.                      log2_size-1))/fft_size;
  89.          twiddle = complex<T>( float(cos(trig_arg)), 
  90.                                float(-sin(trig_arg)));
  92.          for(  top_node = grp_pos; 
  93.                top_node < grp_pos+pts_in_rgt_grp; 
  94.                top_node++){                              
  95.             bot_node = top_node + pts_in_rgt_grp;
  96.             temp = array[bot_node] * twiddle;
  97.             array[bot_node] = array[top_node] - temp;
  98.             array[top_node] += temp;
  99.          }
  100.       } // end of loop over grp_pos
  101.    } // end of loop over stage
  102.    return;
  103. }
  104. //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
  105. template void IfftDitNipo( std::complex<float> *array,
  106.                             int fft_size);
  108. template void FftDitNipo( std::complex<float> *array,
  109.                            int fft_size);