fft.c

在TMS320LF2407上实现快速傅立叶变换(fft)算法

//TMS320LF2407上实现快速傅里叶变换（FFT）

//FFT的程序代码
//(1)主程序
#include   		"f2407_c.h"
#include   		"math.h"
#define     	N	    32 		//    FFT变换的点数  
extern   		void   fft(void);       
extern   		void   resave(void);  
interrupt  		void  phantom(void);  
void    		sysinit(void);
extern  		int input[2*N];   	//    输入数据的存储数组 
int    		indati[N]={0};         
//    -----------------------------------------------------------------------------------
//    128 点 FFT所需的数据
//    采样函数:x=1/4+1/4cos(3*2*pi*f*t)+1/4cos(6*2*pi*f*t)+1/4cos(9*2*pi*f*t);
//    f=50Hz
//    -----------------------------------------------------------------------------------
/*    int indatr[N]={16394,15871,14425,12398,10276    ,8584   ,7767   ,8088    ,9557  , 
                     11913   , 14660    ,17155 ,   18724  ,  18802  ,  17044 ,   13411   , 8197 ,  1995 ,
                     -4389   ,-10071,   -14231  , -16255   ,-15844,   -13057   ,-8309 ,  -2296,   4125  ,
                     10079,    14819,    17843  ,  18969,    18342 ,   16394   ,13739 ,   11055   , 8950  
                     7848,   7921  ,  9070 ,   10961,    13110  ,  14992 ,   16159 ,   16334   ,547,
                     13792   , 11675  ,  9640 ,   8197  ,  7741,    8457,    10264  ,  12815  ,  15554 ,   
                     17812   ,18939  ,  18429  ,  16034  ,  11825 ,   6203  , -156,   -6405,   -11662  ,
                     -15165  , -16394 ,  -15165   ,-11662  , -6405  , -156  ,  6203 ,   11825  ,  16034,
                     18429,    18939  ,  17812  ,  15554 ,   12815   ,10264  ,  8457  ,  7741  , 8197,
                     9640 ,   11675,    13792,    15479 ,   16334 ,   16159,    14992  ,13110  ,  10961  ,
                     9070   ,7921 ,   7848  ,  8950 ,   11055 ,   13739  ,  16393  ,  18342 ,   18969   ,
                     17843  ,  14819  ,  10079   ,4125 ,  -2296 ,  -8309 ,  -13057  , -15844  , -16255  ,
                     -14231 ,  -10071   ,-4389  ,  1995 ,   8197   , 13411 ,   17044 ,   18802 ,   18724  ,
                     17155  ,  14660  ,  11913 ,   9557   ,8088  ,  7767,    8584   , 10276 ,   12398 ,
                     14425  ,  15871             ,
                     };*/
//   -----------------------------------------------------------------------------------
//   32点FFT所需的数据 
//   采样函数:x=1/4+1/4cos(3*2*pi*f*t)+1/4cos(6*2*pi*f*t)+1/4cos(9*2*pi*f*t);
//   f=50Hz ;pi=π;
//   -----------------------------------------------------------------------------------
/*  int indatr[N]={16384, 10270,9551 ,18713 , 8192 ,-14222,-8304,14810,16384,7843,13102 ,15469,8192,12807,
                   18418,-0156,-16384,-0156,-16384, -0156,18418,12807,8192,15469,13102,7843,16383,14810,
                   -8304,-14222,8192,18713,9551,10270,
};*/

int indatr[N]={0x07ff, 0x07ff,0x07ff,0x07ff,0x07ff,0x07ff,0x07ff,0x07ff,
               0x07ff,0x07ff,0x07ff,0x07ff,0x07ff,0x07ff,0x07ff,0x07ff,0x0F801,
               0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,
               0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,0x0F801,
               0x0F801,
};	

//   -----------------------------------------------------------------------------------                              

//    64点 FFT所需的数据
//   采样函数:x=1/4+1/4cos(3*2*pi*f*t)+1/4cos(6*2*pi*f*t)+1/4cos(9*2*pi*f*t);
//   f=50Hz
//   -----------------------------------------------------------------------------------
/*    int indatr[N]={16384 ,  14416,   10270,   7762,   9551 ,  14651 ,  18713,   17034,   8192 , -4387  ,-14222,-15834  ,-8304   ,4123  , 14810   ,18957 ,  16384  , 1
//   ---------------------------------------------------------------
//    128 点 FFT的sin 和 cos值存储表
//   ---------------------------------------------------------------
/*    const int sintab[N]={0x07fff,0x0,0x07fd9,0x0f9b9,0x07f62,0x0f375,0x07e9d,0x0ed38,
		0x07d8a,0x0e708,0x07c2a,0x0e0e7,0x07a7d,0x0dad8,0x07885,0x0d4e1,
		0x07642,0x0cf05,0x073b6,0x0c946,0x070e3,0x0c3aa,0x06dca,0x0be32,
		0x06A6C,0x0B8E4,0x066CE,0x0B3C1,0x062F1,0x0AECD,0x05ED6,0x0AA0C,
		0x05A81,0x0A57F,0x055F4,0x0A12A,0x05133,0x09D0F,0x04C3F,0x09932,
		0x0471C,0x09594,0x041CD,0x09237,0x03C56,0x08F1F,0x036B9,0x08C4B,
		0x030FB,0x089C0,0x02B1E,0x0877D,0x02527,0x08584,0x01F19,0x083D7,
		0x018F8,0x08277,0x012C7,0x08164,0x00C8B,0x0809F,0x00647,0x08029,
		0x00000,0x08001,0x0F9B9,0x08029,0x0F375,0x0809F,0x0ED39,0x08164,
		0x0E708,0x08277,0x0E0E7,0x083D7,0x0DAD9,0x08584,0x0D4E2,0x0877D,
		0x0CF05,0x089C0,0x0C947,0x08C4B,0x0C3AA,0x08F1F,0x0BE33,0x09237,
		0x0B8E4,0x09594,0x0B3C1,0x09932,0x0AECD,0x09D0F,0x0AA0C,0x0A12A,
		0x0A57F,0x0A57F,0x0A12A,0x0AA0C,0x09D0F,0x0AECD,0x09932,0x0B3C1,
		0x09594,0x0B8E4,0x09237,0x0BE33,0x08F1F,0x0C3AA,0x08C4B,0x0C947,
		0x089C0,0x0CF05,0x0877D,0x0D4E2,0x08584,0x0DAD9,0x083D7,0x0E0E7,
		0x08277,0x0E708,0x08164,0x0ED39,0x0809F,0x0F375,0x08029,0x0F9B9
};*/
//   ---------------------------------------------------------------
//   64点 FFT的sin 和 cos值存储表
//   ---------------------------------------------------------------			
/*    const int sintab[N]={	0x7FFF,0x0000,0x7F61 ,0xF375,0x7D89 ,0xE708 ,0x7A7C ,0xDAD9,0x7640,0xCF05 ,0x70E1 ,0xC3AA ,0x6A6C ,0xB8E4 ,0x62F1 ,0xAECD ,
0x5A81,0xA57F,0x5133,0x9D0F,0x471C ,0x9594, 0x3C56, 0x8F1F,
0x30FB,0x89C0 ,0x2527,0x8584 ,0x18F8 ,0x8277 ,0x0C8B ,0x809F,
0x0000 ,0x8001,0xF375,0x809F,0xE708 ,0x8277 ,0xDAD9 ,0x8584,
0xCF05 ,0x89C0 ,0xC3AA,0x8F1F,0xB8E4 ,0x9594 ,0xAECD ,0x9D0F,
0xA57F,0xA57F,0x9D0F,0xAECD,0x9594 ,0xB8E4 ,0x8F1F ,0xC3AA,
0x89C0,0xCF05,0x8584 ,0xDAD9 ,0x8277 ,0xE708 ,0x809F ,0xF375,};*/
//   ---------------------------------------------------------------
//   32 点 FFT的sin 和 cos值存储表
//   ---------------------------------------------------------------
const int sintab[N]={
			0x7FFF,0x0000,0x7D89,0xE708,0x7640,0xCF05,0x6A6C,0xB8E4,
			0x5A81,0xA57F,0x471C,0x9594,0x30FB,0x89C0,0x18F8,0x8277,
			0x0000,0x8001,0xE708,0x8277,0xCF05,0x89C0,0xB8E4,0x9594,
			0xA57F,0xA57F,0x9594,0xB8E4,0x89C0,0xCF05,0x8277,0xE708,
};
extern int table128[];
extern int nom;						//   当nom=1时,FFT 需要归一化处理
main()
{	int i;   
	double x=0,y;
	nom=1;              		 	//   需要归一化处理	
	sysinit();
	for(i=0;i<=255;i++)   input[i]=0;  	//   清除输入数据
    resave();                 		//    把原始的输入数据反序排列                  
	*PCDATDIR=(*PCDATDIR&0x0FF00)|0x01;
	fft( );                     		//    进行FFT运算  
	*PCDATDIR=*PCDATDIR&0x0FF00;
}
void  interrupt  phantom(void)
{	
return;
}		
void sysinit(void)
{	
    *SCSR1=0x81FE;
	*WDCR=0x0E8;
	*IFR=0x0FF;
	*IMR=0x0; 
	WSGR=0;
	*MCRB=0;
	*PCDATDIR=0x100;
}



void interrupt nothing()
{
   return;
}