IIR滤波器设计程序Word文档格式.docx

1、FNCCH（x）log（x+sqrt（x*x-1）FNSH1（x）（exp（x）-exp（-x）/2FNCH1（x）（exp（x）+exp（-x）/2/*/double *bcg（double ap,double as,double wp,double ws,int *n,double *h,int *type）;struct rptr *bsf（double *c,int ni,double *f1,double *f2,int nf,struct rptr *ptr,int *no）;double *pnpe（double *a,int m,int n,double *b,int *mn）

2、;double *ypmp（double *a,int m,double *b,int n,double *c,int *mn）;void lowpass_input（double *wp,double *ws,double *ap,double *ar,double *f1,double *f2,int *nf）;void highpass_input（double *wp,double *ws,double *ap,double *ar,double *f1,double *f2,int *nf）;void bandpass_input（double *wp,double *ws,doub

3、le *ap,double *ar,double *f1,double *f2,int *nf）;void draw_image（double *x,int m,char *title1,char *title2,char *xdis1,char *xdis2,int dis_type）;void main（void）double *f1,*f2,*hwdb;double *h=NULL;int N,nf,ns,nz,i,j,k,ftype,type;COMPLEX hwdb1,hwdb2;double wp,ws,ap,as,jw,amp1,amp2;char title80,tmp20;s

4、truct rptr *ptr=NULL;/* printf（%lf,PI）;getch（）;N=500;f1=（double *）calloc（4,sizeof（double）;f2=（double *）calloc（4,sizeof（double）;hwdb=（double *）calloc（N+2,sizeof（double）;if （hwdb=NULL）printf（n Not enough memory to allocate!）;exit（0）;n1.Lowpass 2.Highpass 3.bandpassnPlease select the filter type:scanf（

5、%d,&ftype）;switch（ftype）case 1:lowpass_input（&wp,&ws,&ap,&as,f1,f2,&nf）;break;case 2:highpass_input（&case 3:bandpass_input（&default:h=bcg（ap,as,wp,ws,&ns,h,&type）;nThe analog filter denominator coefficients of Ha（s）:for（i=0;iai,i,ptr-bi）;nnPress any key to calculate the filter response of H（z）.nWait

6、ting for calculating./* Calculate the magnitude-frequency response*/for（k=0;kai*cos（i*jw）;hwdb2.real+=ptr-bi*cos（i*jw）;hwdb1.image+=ptr-ai*sin（i*jw）;hwdb2.image+=ptr-bi*sin（i*jw）;amp1=（pow（hwdb1.real,2）+pow（hwdb1.image,2）;amp2=（pow（hwdb2.real,2）+pow（hwdb2.image,2）;if（amp1=0） amp1=1e-90;if（amp2=0） am

7、p2=1e-90;hwdbk=10*log10（amp1/amp2）;if（hwdbkb）;a）;free（h）;free（hwdb）;free（f2）;free（f1）;/*/void lowpass_input（double *wp,double *ws,double *ap,double *ar,double *f1,double *f2,int *nf）double fp,fr,fs;nPlease input the Fp,Ap,Fr,Ar,Fs valuenFp,Ap:Passband frequency（Hz） and MAXAttenuation（dB）nFr,Ar:Stopb

8、and frequency（Hz） and MINAttenuation（dB）nFs is the sample frequency（Hz） Lowpass filternInput parameters Fp,Ap,Fr,Ar,Fs:%lf,%lf,%lf,%lf,%lffp,ap,&fr,ar,&fs）;if（fpfr）|（*ap*ar）|（fs2*fr）;*wp=tan（PI*fp/fs）;*ws=tan（PI*fr/fs）;*f1=-1.0;*（f1+1）=1.0;*f2=1.0;*（f2+1）=1.0;*nf=1;/*/void highpass_input（double *wp,

9、double *ws,double *ap,double *ar,double *f1,double *f2,int *nf）nFs is the sample frequency（Hz） highpass filterif（fp*ar）|（fs2*fp）while（fp*ar）|（fsfp2）|（fp1fr2）|（*ap2*fr2）while（fp12*fr2）;wp1=2*PI*fp1/fs;wr1=2*PI*fr1/fs;wp2=2*PI*fp2/fs;wr2=2*PI*fr2/fs;cw0=sin（wp1+wp2）/（sin（wp1）+sin（wp2）;pwp1=fabs（cw0-co

10、s（wp1）/sin（wp1）;pws1=fabs（cw0-cos（wr1）/sin（wr1）;pwp2=fabs（cw0-cos（wp2）/sin（wp2）;pws2=fabs（cw0-cos（wr2）/sin（wr2）;if（fabs（pws1-pwp1）real=-wc*FNSH1（x）*sin（y）;image=-wc*FNCH1（x）*cos（y）;c=（pow（10.0,（0.1*ap）-1.0）/（pow（10.0,（0.1*as）-1.0）;*n=（int）（fabs（log（c）/log（wp/ws）/2.0）+0.99999）;b=（COMPLEX *）calloc（*n+

11、2,sizeof（COMPLEX）;wc=wp/pow（pow（10.0,0.1*ap）-1.0,1.0/（2.0*（*n）;a=pow（wc,（double）（*n）;p=PI*（0.5+（2.0*i+1.0）/2.0/（*n）;real=wc*cos（p）;image=wc*sin（p）;nThe order of prototype filter is:,*n）;/* b1=（COMPLEX*）calloc（*n+2,sizeof（COMPLEX）;b2=（COMPLEX*）calloc（*n+2,sizeof（COMPLEX）;h=（double *）calloc（*n+2）,size

12、of（double）;if（h=NULL）b1-real=-（b-real）;image=-（b-image）;（b1+1）-real=1.0;image=0.0;if（*n!=1）for（i=1;I;K+）cs1=（b1+k）-real-（b1+k+1）-real*（b+i）-real;cs2=（b1+k）-image-（b1+k+1）-image;（b2+k+1）-real=cs1+（b1+k+1）-image*（b+i）-image=cs2-（b1+k+1）-b2-real=-（b1-real-b1-image=-（b1-image+b1-（b2+i+1）-real=（b1+i）-image=（b1+i）-=i+1;（b1+k）-real=（b2+k）-image=（b2+k）-（b2+k）-real=0.0;=*n;hi=（b1+i）-nz%2d=%16fnz0=%16f,nz1=%16f,nz2=%16f,nz3=%16f,nz4=%16f,1.0,2.6131/wc,3.4142/pow（wc,2）,2.6131/pow（wc,3）,1/a）;=*n-1;ppi=xs*n-1i;hi=ppi/pow（wc,i）;free（b）;/* free（b1）;free（b2）;return h;/*/*