Capsim Block Documentation
Star implements direct form IIR digital filter.
| Port | Type | Name | |
|---|---|---|---|
| 0 | float | x |
| Port | Type | Name | |
|---|---|---|---|
| 0 | float | y |
| Num | Description | Type | Name | Default Value | |
|---|---|---|---|---|---|
| 0 | File with direct form filter parameters | file | filename | tmp.df |
| Num | Type | Name | Initial Value | Description |
|---|---|---|---|---|
| 0 | float* | b_A | ||
| 1 | float* | x_A | ||
| 2 | int | m | ||
| 3 | int | n | ||
| 4 | float | fs | ||
| 5 | float | wnorm | ||
| 6 | int | nt |
float temp1,temp2;
double sum;
int i,j,np1;
float x1,yr;
FILE *ird_F;
|
|---|
/*
* open file containing filter coefficients. Check
* to see if it exists.
*
*/
if( (ird_F = fopen(filename,"r")) == NULL) {
fprintf(stderr,"dffil: File could not be opened \n");
return(4);
}
/*
* Read in the filter coefficients and filter parameters.
*
*/
fscanf(ird_F,"%d %d",&m,&n);
nt=m+n;
b_A = (float *)malloc((nt+5)*sizeof(float));
if(b_A == NULL) {
fprintf(stderr,"dffil: could not allocate space \n");
return(5);
}
x_A = (float *)malloc((nt+5)*sizeof(float));
if(x_A == NULL) {
fprintf(stderr,"dffil: could not allocate space \n");
return(6);
}
for(i=0; i |
|---|
while (IT_IN(0)) {
x1 = x(0);
/* *** ***
* *** the following loop calculates the filter response ***
* *** ***
*/
fprintf(stderr,"yr= %e x1= %e\n",yr,x1);
yr= - y(1);
/* *** ***
* *** shift the new value of x(0) into the vector x ***
* *** ***
*/
temp2=x1;
for(i=0; i< m; i++) {
temp1=x_A[i];
x_A[i]=temp2;
temp2=temp1;
}
/* *** ***
* *** shift -y into vector x ***
* *** ***
*/
if ( n != 0) {
temp2=yr;
for(i=m; i |
|---|
free(b_A); free(x_A); |
|---|
/* Capsim (r) Text Mode Kernel (TMK) Star Library (Blocks)
Copyright (C) 1989-2017 Silicon DSP Corporation
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
http://www.silicondsp.com
Silicon DSP Corporation
Las Vegas, Nevada
*/
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/* dffil.s */
/***********************************************************************
dffil()
************************************************************************
Star implements direct form IIR digital filter.
Parameter: (file) File with the filter coefficients and parameters
The inputs from the file are as follows;
num: Number of numerator coefficients
numerator coefficients
denum: Number of denominator coefficients
denominator coefficients
*/
/**********************************************************************
c Direct form filter coefficients are read from a file *
c The inputs from the file are as follows: *
c m n : where m is the number of zeroes plus one *
c n is the number of poles *
c b(i) i=1,m+n : the numerator and denominator coefficients *
c *
c In the z domain: *
c Y(z)/X(z)=C(z)/[1+A(z)] *
c C(z)=c0+c1*z**(-1)+... cm-1*z**(-m+1) *
c A(z)=a1*z**(-1)+...+an*z**(-n) *
c *
c The subroutine calculates the vector inner product y(k)=x_Tb_ *
c x_ where x_=[x(k) x(k-1) ... x(k-m+1) -y(k-1) -y(k-2) ... -y(k-n)] T
c b_=[c0 c1 ... cm-1 a1 a2 ... an ]T *
c *
c *
c**********************************************************************
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