IIR数字滤波器实现程序
这是从书上还有很多网上资料找的说的比较多的IIR程序，我觉得这个程序有问题啊，程序里面fYn应该一直是0啊！！！#include "DSP281x_Device.h" // DSP281x Headerfile Include File#include "DSP281x_Examples.h" // DSP281x Examples Include File
#include "f2812a.h"
#include"math.h"
#define IIRNUMBER 2
#define SIGNAL1F 1000
#define SIGNAL2F 4500
#define SAMPLEF10000
#define PI 3.1415926
float InputWave();
float IIR();
float fBn={ 0.0,0.7757 };
float fAn={ 0.1122,0.1122 };
float fXn={ 0.0 };
float fYn={ 0.0 };
float fInput,fOutput;
float fSignal1,fSignal2;
float fStepSignal1,fStepSignal2;
float f2PI;
int i;
float fIn,fOut;
int nIn,nOut;
main(void)
{
nIn=0; nOut=0;
f2PI=2*PI;
fSignal1=0.0;
fSignal2=PI*0.1;
// fStepSignal1=2*PI/30;
// fStepSignal2=2*PI*1.4;
fStepSignal1=2*PI/50;
fStepSignal2=2*PI/2.5;
while ( 1 )
{
fInput=InputWave();
fIn=fInput;
nIn++; nIn%=256;
fOutput=IIR();
fOut=fOutput;
nOut++;
if ( nOut>=256 )
{
nOut=0; /* 请在此句上设置软件断点 */
}
}
}
float InputWave()
{
for ( i=IIRNUMBER-1;i>0;i-- )
{
fXn=fXn;
fYn=fYn;
}
fXn=sin(fSignal1)+cos(fSignal2)/6.0;
fYn=0.0;
fSignal1+=fStepSignal1;
if ( fSignal1>=f2PI ) fSignal1-=f2PI;
fSignal2+=fStepSignal2;
if ( fSignal2>=f2PI ) fSignal2-=f2PI;
return(fXn);
}
float IIR()
{
float fSum;
fSum=0.0;
for ( i=0;i<IIRNUMBER;i++ )
{
fSum+=(fXn*fAn);
fSum+=(fYn*fBn);
}
return(fSum);
}
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