/* | |
** Copyright 2003-2010, VisualOn, Inc. | |
** | |
** Licensed under the Apache License, Version 2.0 (the "License"); | |
** you may not use this file except in compliance with the License. | |
** You may obtain a copy of the License at | |
** | |
** http://www.apache.org/licenses/LICENSE-2.0 | |
** | |
** Unless required by applicable law or agreed to in writing, software | |
** distributed under the License is distributed on an "AS IS" BASIS, | |
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
** See the License for the specific language governing permissions and | |
** limitations under the License. | |
*/ | |
/*********************************************************************** | |
* File: weight_a.c * | |
* * | |
* Description:Weighting of LPC coefficients * | |
* ap[i] = a[i] * (gamma ** i) * | |
* * | |
************************************************************************/ | |
#include "typedef.h" | |
#include "basic_op.h" | |
void Weight_a( | |
Word16 a[], /* (i) Q12 : a[m+1] LPC coefficients */ | |
Word16 ap[], /* (o) Q12 : Spectral expanded LPC coefficients */ | |
Word16 gamma, /* (i) Q15 : Spectral expansion factor. */ | |
Word16 m /* (i) : LPC order. */ | |
) | |
{ | |
Word32 num = m - 1, fac; | |
*ap++ = *a++; | |
fac = gamma; | |
do{ | |
*ap++ =(Word16)(((vo_L_mult((*a++), fac)) + 0x8000) >> 16); | |
fac = (vo_L_mult(fac, gamma) + 0x8000) >> 16; | |
}while(--num != 0); | |
*ap++ = (Word16)(((vo_L_mult((*a++), fac)) + 0x8000) >> 16); | |
return; | |
} | |