/****************************************************************** | |
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++; | |
} | |
} | |