FIR数字滤波器的DSP课程设计

StartCpuTimer2(); /*开中断*/

IER |= M_INT14; EINT; InitAdc(); for(;;){

if (adconvover==1){

/*fir滤波处理*/ for(i=0;i

Ad_data_signed[i]=(short)(Ad_data[i]-0x5300);

fir_filter(Ad_data_signed,hfir,filter_result,ORDER_FIR,DataLong,ROUND_FIR);

}

}

adconvover=0;

}

interrupt void ad(void) {

IFR=0x0000;

PieCtrl.PIEACK.all=0xffff; if(adconvover==0){

Ad_data[convcount] = AdcRegs.RESULT0;

convcount++;

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}

if (convcount==DataLong){

convcount=0;

adconvover=1;//接满标志

}

}

interrupt void ISRTimer2(void) { }

FIR_filter.c代码：

//const short x[]:输入信号的缓冲数组，short类型 //const short h[]：滤波器的系数数组，short类型 //short y[]：输出信号的缓冲数组，short类型 //n:滤波器长度

//m:输入信号的长度，即x[]的长度

//s:生成整型的滤波器系数时使用的移位数目

void fir_filter(const short x[],const short h[],short y[],int n,int m,int s) {

int i,j; long y0; long acc;

_nassert(m>=16);

AdcRegs.ADC_ST_FLAG.bit.INT_SEQ1_CLR=1; AdcRegs.ADCTRL2.bit.SOC_SEQ1=1;

_nassert(n>=16); for(j=0;j

for(i=0;i

if(i+j>=m) break; else {

y0=(long)x[i+j]*(long)h[i]; acc=acc+y0; } }

*y++=(short)(acc>>s); } }

五、系统仿真

5.1 仿真设置

1.fir_filter(Ad_data_signed,hfir,filter_result,ORDER_FIR,DataLong,ROUND_FIR)和adconvover=0处设置断点

2.在Graph Property Dialog中设置Start Address和Display Type如图5.1、图5.2、图5.3、图5.4

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图 5.1 Graph Property Dialog

图 5.2 Graph Property Dialog