iirbcf example.c

自己编的数值计算方法的c语言实现源程序。

#include"stdio.h"
#include"iirbcf.c"
#include"gainc.c"

void main()
{	int i,k,n,ns,itilt,band;
	double a[50],b[50],x[300],y[300];
	double f1,f2,f3,f4,fc,fr,fs,flc,fls,fhc,fhs,freq,db;
	char fname[40];
	FILE *fp;
	printf("enter 1 for Chebyshev I, 2 for Chebyshev II,3 for Butterworth\n");
	scanf("%d",&ifilt);
	printf("enter 1 for lowpass, 2 for highpass, 3 for bandpass, 4 for bandstop\n");
	scanf("%d",&band);
	n=(band<=2)?2:4;
	printf("enter the number of filter section\n");
	scanf("%d",&ns);
	printf("enter sample frequence fs\n");
	scanf("%lf", &fs);
	if(ifilt<=2)
	{	switch(band)
		{	case 1:
			case 2:
			{	printf("enter passband edge frequency fc\n");
				scanf("%lf",&fc);
				printf("enter stopband edge frequency fr\n");
				scanf("%lf",&fr);
				if(band==1)
				{	f1=fc;
					f2=fr;
				}
				else
				{	f1=fr;
					f2=fc;
				}
				f3=f4=0.0;
				case 3:
				case 4:
				{	printf("enter the lower passband edge frequency flc\n");
				scanf("%lf",&flc);
					printf("enter the higher passband edge frequency fhc\n");
				scanf("%lf",&fhc);
					printf("enter the lower stopband edge frequency fls\n");
				scanf("%lf",&fls);
					printf("enter the higher stopband edge frequency fhs\n");
				scanf("%lf",&fhs);
				if(band==3)
				{	f1=fls;					
					f2=flc;
					f3=fhc;
					f4=fhs;
				}
				else
				{	f1=flc;
					f2=fls;
					f3=fhs;
					f4=fhc;
				}
			}
		}
		printf("enter stopband attenuation(dB)\n");
		scanf("%lf",&db);
	}
	else
	{	switch(band)
		{	case 1:
			case 2:
			{	printf("enter passband edge frequency fc\n");
				scanf("%lf",&fc);
				f1=f2=f3=f4=0.0;
				if(band==1)
				{	f1=fc;}
				else
				{	f2=fc;}
				break;
			}
			case 3:
			case 4:
			{	printf("enter the lower passband edge frequency flc\n");
				scanf("%lf",&flc);
				printf("enter the higher passband edge frequency fhc\n");
				scanf("%lf",&fhc);
				f1=f2=f3=f4=0.0;
				if(band==3)
				{ 	f2=flc;
					f3=fhc;
				}
				else
				{	f1=flc;
					f4=fhc;
				}
			}
		}
	}
	f1=f1/fs;
	f2=f2/fs;
	f3=f3/fs;
	f4=f4/fs;
	iirbcf(ifilt,band,ns,n,f1,f2,f3,f4,db,b,a);
	for(k=0;k<ns;k++)
	{	printf("\nsection %d\n\n",k+1);
		for(i=0;i<=n;i++)
		{	printf("  b[%d][%d]=%10.7lf ",k,i,b[k*(n+1)+i]);
			if(((i%2)==0)&&(i!=0))	printf("\n");
		}
		printf("\n");
		for(i=0;i<=n;i++)
		{	printf("  a[%d][%d]=%10.7lf ",k,i,a[k*(n+1)+i]);
			if(((i%2)==0)&&(i!=0))	printf("\n");
		}		
		printf("\n");
	}
	printf("\nenter file name of magnitude response\n");
	scanf("%s",fname);
	if((fp=fopen(fname,"w"))==NULL)
	{	printf("cannot open file %s\n",fname);
		exit(0);
	}
	gainc(b,a,n,ns,x,y,300,2);
	for(i=0;i<300;i++)
	{	freq=i*0.5/300.0;
		fprintf(fp,"%lf  %lf\n",freq,x[i]);
	}
	fclose(fp);
}