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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
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7
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8
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9
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10 hpInput.c
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11
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12 Copyright (C) The Internet Society (2004).
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13 All Rights Reserved.
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14
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15 ******************************************************************/
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16
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17 #include "constants.h"
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18
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19 /*----------------------------------------------------------------*
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20 * Input high-pass filter
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21 *---------------------------------------------------------------*/
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22
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23 void hpInput(float *In, /* (i) vector to filter */
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24 int len, /* (i) length of vector to filter */
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25 float *Out, /* (o) the resulting filtered vector */
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26 float *mem /* (i/o) the filter state */
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27 )
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28 {
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29 int i;
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30 float *pi, *po;
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31
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32 /* all-zero section */
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33
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34 pi = &In[0];
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35 po = &Out[0];
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36 for (i = 0; i < len; i++) {
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37 *po = hpi_zero_coefsTbl[0] * (*pi);
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38 *po += hpi_zero_coefsTbl[1] * mem[0];
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39 *po += hpi_zero_coefsTbl[2] * mem[1];
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40
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41 mem[1] = mem[0];
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42 mem[0] = *pi;
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43 po++;
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44 pi++;
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45
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46 }
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47
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48 /* all-pole section */
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49
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50 po = &Out[0];
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51 for (i = 0; i < len; i++) {
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52 *po -= hpi_pole_coefsTbl[1] * mem[2];
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53 *po -= hpi_pole_coefsTbl[2] * mem[3];
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54
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55 mem[3] = mem[2];
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56 mem[2] = *po;
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57 po++;
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58
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59
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60
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61
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62
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63 }
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64 }
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