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1
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2 /******************************************************************
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3
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4 iLBC Speech Coder ANSI-C Source Code
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5
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6 hpOutput.c
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7
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8 Copyright (C) The Internet Society (2004).
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9 All Rights Reserved.
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10
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11 ******************************************************************/
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12
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13 #include "constants.h"
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14
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15 /*----------------------------------------------------------------*
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16 * Output high-pass filter
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17 *---------------------------------------------------------------*/
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18
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19 void hpOutput(float *In, /* (i) vector to filter */
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20 int len, /* (i) length of vector to filter */
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21 float *Out, /* (o) the resulting filtered vector */
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22 float *mem /* (i/o) the filter state */
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23 )
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24 {
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25 int i;
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26 float *pi, *po;
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27
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28 /* all-zero section */
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29
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30 pi = &In[0];
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31 po = &Out[0];
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32 for (i = 0; i < len; i++) {
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33 *po = hpo_zero_coefsTbl[0] * (*pi);
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34 *po += hpo_zero_coefsTbl[1] * mem[0];
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35 *po += hpo_zero_coefsTbl[2] * mem[1];
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36
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37 mem[1] = mem[0];
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38 mem[0] = *pi;
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39 po++;
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40 pi++;
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41
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42 }
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43
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44 /* all-pole section */
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45
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46 po = &Out[0];
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47 for (i = 0; i < len; i++) {
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48 *po -= hpo_pole_coefsTbl[1] * mem[2];
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49 *po -= hpo_pole_coefsTbl[2] * mem[3];
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50
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51 mem[3] = mem[2];
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52 mem[2] = *po;
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53 po++;
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54 }
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55 }
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