www.pudn.com > source.rar > COR_FUNC.C

/* ITU-T G.729 Software Package Release 2 (November 2006) */ 
/* 
   ITU-T G.729 Annex C - Reference C code for floating point 
                         implementation of G.729 
                         Version 1.01 of 15.September.98 
*/ 
 
/* 
---------------------------------------------------------------------- 
                    COPYRIGHT NOTICE 
---------------------------------------------------------------------- 
   ITU-T G.729 Annex C ANSI C source code 
   Copyright (C) 1998, AT&T, France Telecom, NTT, University of 
   Sherbrooke.  All rights reserved. 
 
---------------------------------------------------------------------- 
*/ 
 
/* 
 File : COR_FUNC.C 
 Used for the floating point version of both 
 G.729 main body and G.729A 
*/ 
 
/* Functions corr_xy2() and cor_h_x()   */ 
 
#include "typedef.h" 
#include "version.h" 
#ifdef VER_G729A 
 #include "ld8a.h" 
#else 
 #include "ld8k.h" 
#endif 
 
/*---------------------------------------------------------------------------- 
 * corr_xy2 - compute the correlation products needed for gain computation 
 *---------------------------------------------------------------------------- 
 */ 
void corr_xy2( 
 FLOAT xn[],            /* input : target vector x[0:l_subfr] */ 
 FLOAT y1[],            /* input : filtered adaptive codebook vector */ 
 FLOAT y2[],            /* input : filtered 1st codebook innovation */ 
 FLOAT g_coeff[]        /* output:  , -2 , and 2*/ 
) 
{ 
   FLOAT y2y2, xny2, y1y2; 
   int i; 
 
   y2y2= (F)0.01; 
   for (i = 0; i < L_SUBFR; i++) y2y2 += y2[i]*y2[i]; 
   g_coeff[2] = y2y2 ; 
 
   xny2 = (F)0.01; 
   for (i = 0; i < L_SUBFR; i++) xny2+= xn[i]*y2[i]; 
   g_coeff[3] = (F)-2.0* xny2; 
 
   y1y2 = (F)0.01; 
   for (i = 0; i < L_SUBFR; i++) y1y2 += y1[i]*y2[i]; 
   g_coeff[4] = (F)2.0* y1y2 ; 
 
   return; 
 
} 
 
/*--------------------------------------------------------------------------* 
 *  Function  cor_h_x()                                                     * 
 *  ~~~~~~~~~~~~~~~~~~~~                                                    * 
 * Compute  correlations of input response h[] with the target vector X[].  * 
 *--------------------------------------------------------------------------*/ 
 
void cor_h_x( 
     FLOAT h[],        /* (i) :Impulse response of filters      */ 
     FLOAT x[],        /* (i) :Target vector                    */ 
     FLOAT d[]         /* (o) :Correlations between h[] and x[] */ 
) 
{ 
   int i, j; 
   FLOAT  s; 
 
   for (i = 0; i < L_SUBFR; i++) 
   { 
     s = (F)0.0; 
     for (j = i; j <  L_SUBFR; j++) 
       s += x[j] * h[j-i]; 
     d[i] = s; 
   } 
 
   return; 
}