低通濾波c語言
『壹』 在設計FIR數字低通濾波器器時,用MATLAB生成了c語言頭文件,在編寫單片機程序時該怎樣利用那個頭文件
再將matlab里邊的卷積函數轉成C，直接調用就行了~~~~
或者你直接用C語言使用for寫個卷積函數，將B和信號做卷積。
real64_T是double，寫函數的時候注意點~
『貳』 求教用C語言實現低通濾波器
float middle_filter(float middle_value [] , intcount)
{
float sample_value, data;
int i, j;
for (i=1; i for(j=count-1; j>=i,--j){
if(middle_value[j-1]=middle_value[j]{
data=middle_value[j-1];
middle_value[j-1]=middle_value[j]
middle_value[j]=data;
}
}
sample_value=middle_value(count-1)/2];
return(sample_value);
}
『叄』 求：c語言數字濾波器；要求：1Khz低通；20個數x0，x1，x2----x19；結果y0---y19
1，低通濾波器傳函k*f^2/(s^2+s*f/Q+f^2),確定你的電壓增壓k和品質因數，還有截止頻率f。我就以f=1k，q=0.707，k=1為例。
2，進行離散化。離散化方法以雙線性變換為例。。。。然後得到Transfer function:
1.039e-005 z + 6.53e-006
------------------------
z^2 - 1.243 z + 0.2431
Sampling time: 0.001
3，然後就改寫成差分方程。。。。把z^(-n)中的(-n)寫成(k-n)即可。自己移相試試 就知道了。
『肆』 如何用c語言實現截止頻率為200hz的巴特沃斯低通濾波器
/* 6th Order Low Pass Butterworth */
/* Bilinear Transformation with Prewarping */
/* Sample Frequency = 100.0 Hz */
/* Standard Form */
/* Arithmetic Precision = 4 Digits */
/* */
/* Pass Band Frequency = 35.00 Hz */
/* */
/******************************************************************************/
/* */
/* Input Variable Definitions: */
/* Inputs: */
/* invar float The input to the filter */
/* initvar float The initial value of the filter */
/* setic int 1 to initialize the filter to the value of initvar */
/* */
/* There is no requirement to ever initialize the filter. */
/* The default initialization is zero when the filter is first called */
float DigFil(invar, initval, setic)
float invar, initval; int setic;
{
float sumnum, sumden; int i;
static float delay[7] = {0.0,0.0,0.0,0.0,0.0,0.0,0.0};
static float znum[7] = {
.1477,
.8864,
2.216,
2.955,
2.216,
.8864,
.1477
};
static float zden[6] = {
2.183e-02,
.2099,
.8779,
2.055,
2.91,
2.38
};
if (setic==1){
for (i=0;i<=6;i++) delay[i] = .1058*initval;
return initval;
}
else{
sumden=0.0;
sumnum=0.0;
for (i=0;i<=5;i++){
delay[i] = delay[i+1];
sumden += delay[i]*zden[i];
sumnum += delay[i]*znum[i];
}
delay[6] = invar-sumden;
sumnum += delay[6]*znum[6];
return sumnum;
}
}
『伍』 y=x*wc/(s+wc)這個一階低通濾波器用c語言代碼如何實現呢
s32 tmp;
tmp = x- y;
y += tmp*Wc;
『陸』 c語言設計巴特沃斯低通濾波器fp=9khz,fs=15khz,ap=1dB,as=70dB
能實行，c語言不能顯示圖像，但是你要懂得如何用c調用matlab，過程比較復雜，這個程序任何參數都可以用，不限制
#include<engine.h>
#include<math.h>
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
doublecalcN(doublefp,doubleap,doublefs,doubleas)
{
doublei=pow(10,(as/10))-1;
doubletmp=ap/10;
doublej=pow(10,tmp)-1;
doublek=log10((i/j));
doublet=log10(fs/fp);
doubleN=0.5*k/t+1;
returnN;
};
intmain(void)
{
intfp,ap,fs,as;
printf("請輸入fp:");
scanf("%d",&fp);
printf("請輸入ap:");
scanf("%d",&ap);
printf("請輸入fs:");
scanf("%d",&fs);
printf("請輸入as:");
scanf("%d",&as);
intf=calcN(fp,ap,fs,as);
printf("N=%d ",f);
charlin[40];
char*str="N= ";
lin[0]=' ';
charin[4];
itoa(f,in,10);
strcat(lin,str);
strcat(lin,in);
strcat(lin,";");
///////////////////////////////////////////////////////////
Engine*ep;
if(!(ep=engOpen(NULL)))
{
printf("openfailed!pleasetryagain ");
}
engSetVisible(ep,0);
//mxArray*xx=mxCreateDoubleMatrix(1,N,mxREAL);
//mxArray*yy=mxCreateDoubleMatrix(1,N,mxREAL);
//memcpy(mxGetPr(xx),N*sizeof(double));
//memcpy(mxGetPr(yy),N*sizeof(double));
//engPutVariable(ep,"xx",xx);
//engPutVariable(ep,"yy",yy);
engEvalString(ep,"n=0:0.01:2;");
engEvalString(ep,lin);
engEvalString(ep,"[z,p,k]=buttap(N);");
engEvalString(ep,"[b,a]=zp2tf(z,p,k);");
engEvalString(ep,"[H,w]=freqs(b,a,n);");
engEvalString(ep,"magH=(abs(H)).^2;");
engEvalString(ep,"plot(w,magH);");
engEvalString(ep,"axis([0201])");
engEvalString(ep,"xlabel('w/wc');");
engEvalString(ep,"ylabel('|H(jw)|^2');");
engEvalString(ep,"title('');");
engEvalString(ep,"grid;");
getchar();
//mxDestroyArray(xx);
//mxDestroyArray(yy);
//engClose(ep);
return0;
}
