刚刚接触DSP  网上找了一个DSP的设计实验   在CCS中可以运行  但是源代码有点看不懂  
有没有大侠能帮小弟来答疑解惑   比如一些初始化的作用  函数如何设计的   
#include "myapp.h"
#include "ICETEK-VC5509-EDU.h"
#include "scancode.h"
#include <math.h>

#define FIRNUMBER 25
#define SIGNAL1F 1000
#define SIGNAL2F 4500
#define SAMPLEF  10000
#define PI 3.1415926

float InputWave();
float FIR();

float fHn[FIRNUMBER]={ 0.0,0.0,0.001,-0.002,-0.002,0.01,-0.009,
                       -0.018,0.049,-0.02,0.11,0.28,0.64,0.28,
                       -0.11,-0.02,0.049,-0.018,-0.009,0.01,
                       -0.002,-0.002,0.001,0.0,0.0
                     };
float fXn[FIRNUMBER]={ 0.0 };
float fInput,fOutput;
float fSignal1,fSignal2;
float fStepSignal1,fStepSignal2;
float f2PI;
int i;
float fIn[256],fOut[256];
int nIn,nOut;

main()
{
        nIn=0; nOut=0;
        f2PI=2*PI;
        fSignal1=0.0;
        fSignal2=PI*0.1;
        fStepSignal1=2*PI/30;
        fStepSignal2=2*PI*1.4;
        while ( 1 )
        {
                fInput=InputWave();
                fIn[nIn]=fInput;
                nIn++; nIn%=256;
                fOutput=FIR();
                fOut[nOut]=fOutput;
                nOut++;                                /* break point */
                if ( nOut>=256 )
                {
                        nOut=0;                
                }
        }
}

float InputWave()
{
        for ( i=FIRNUMBER-1;i>0;i-- )
                fXn=fXn[i-1];
        fXn[0]=sin((double)fSignal1)+cos((double)fSignal2)/6.0;
        fSignal1+=fStepSignal1; 
        if ( fSignal1>=f2PI )        fSignal1-=f2PI;
        fSignal2+=fStepSignal2;
        if ( fSignal2>=f2PI )        fSignal2-=f2PI;
        return(fXn[0]);
}

float FIR()
{
        float fSum;
        fSum=0;
        for ( i=0;i<FIRNUMBER;i++ )
        {
                fSum+=(fXn*fHn);
        }
        return(fSum);
}