Iir - Analog Devices VISUALDSP++ 3.5 Manual

iir

infinite impulse response filter
Synopsis
#include <filter.h>
void iir_fr16(x,y,n,s)
const fract16 x[];
fract16 y[];
int n;
iir_state_fr16 *s
The function uses the following structure to maintain the state of the
filter.
typedef struct
{
fract16 *c;
fract16 *d;
int k;
} iir_state_fr16;
Description
The
iir_fr16
impulse response (IIR) filter. It generates the filtered response of the input
data and stores the result in the output vector
x
samples and the length of the output vector is specified by the argument
The function maintains the filter state in the structured variable
must be declared and initialized before calling the function. The macro
, in the
iir_init
and is defined as:
#define iir_init(state, coeffs, delay, stages)
(state).c = (coeffs);
(state).d = (delay);
(state).k = (stages)
VisualDSP++ 3.5 C/C++ Compiler and Library Manual
for ADSP-219x DSPs
/* Input sample vector x
/* Output sample vector y
/* Number of input samples
/* Pointer to filter state structure */
/* coefficients
/* start of delay line
/* number of bi-quad stages
function implements a bi-quad, canonical form, infinite
header file, is available to initialize the structure
filter.h
\
\
DSP Run-Time Library
. The number of input
y
, which
s
\
*/
*/
*/
*/
*/
*/
.
n
4-83