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