Analog Devices VISUALDSP++ 3.5 Manual page 477

fir_interp
FIR interpolation filter
Synopsis
#include <filter.h>
void fir_interp_fr16(x,y,n,s)
const fract16 x[];
fract16 y[];
int n;
fir_state_fr16 *s;
The function uses the following structure to maintain the state of the
filter.
typedef struct
{
fract16 *h;
fract16 *d;
fract16 *p;
int k;
int l;
} fir_state_fr16;
Description
The
fir_interp_fr16
It generates the interpolated filtered response of the input data
stores the result in the output vector
specified by the argument
where l is the interpolation index.
n*l
The function maintains the filter state in the structured variable
must be declared and initialized before calling the function. The macro
, in the
fir_init
and is defined as:
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 */
/* Filter coefficients
/* Start of delay line
/* Read/Write pointer
/* Number of coefficients
/* Interpolation/decimation index
function performs an FIR-based interpolation filter.
, and the size of the output vector should be
n
header file, is available to initialize the structure
filter.h
DSP Run-Time Library
. The number of input samples is
y
*/
*/
*/
*/
*/
*/
*/
*/
and
x
, which
s
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