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/******************************************************************
iLBC Speech Coder ANSI-C Source Code
hpInput.c
Copyright (C) The Internet Society (2004).
All Rights Reserved.
******************************************************************/
#include "constants.h"
/*----------------------------------------------------------------*
* Input high-pass filter
*---------------------------------------------------------------*/
void hpInput(
float *In, /* (i) vector to filter */
int len, /* (i) length of vector to filter */
float *Out, /* (o) the resulting filtered vector */
float *mem /* (i/o) the filter state */
){
int i;
float *pi, *po;
/* all-zero section*/
pi = &In[0];
po = &Out[0];
for (i=0; i<len; i++) {
*po = hpi_zero_coefsTbl[0] * (*pi);
*po += hpi_zero_coefsTbl[1] * mem[0];
*po += hpi_zero_coefsTbl[2] * mem[1];
mem[1] = mem[0];
mem[0] = *pi;
po++;
pi++;
}
/* all-pole section*/
po = &Out[0];
for (i=0; i<len; i++) {
*po -= hpi_pole_coefsTbl[1] * mem[2];
*po -= hpi_pole_coefsTbl[2] * mem[3];
mem[3] = mem[2];
mem[2] = *po;
po++;
}
}
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