/* | |
** 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: hp_wsp.c * | |
* Description: * | |
* 3nd order high pass filter with cut off frequency at 180Hz * | |
* Algorithm: * | |
* * | |
* y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2] + b[3]*x[i-3] * | |
* + a[1]*y[i-1] + a[2]*y[i-2] + a[3]*y[i-3]; * | |
* * | |
* float a_coef[HP_ORDER]= { * | |
* -2.64436711600664f, * | |
* 2.35087386625360f, * | |
* -0.70001156927424f}; * | |
* * | |
* float b_coef[HP_ORDER+1]= { * | |
* -0.83787057505665f, * | |
* 2.50975570071058f, * | |
* -2.50975570071058f, * | |
* 0.83787057505665f}; * | |
* * | |
*************************************************************************/ | |
#include "typedef.h" | |
#include "basic_op.h" | |
#include "oper_32b.h" | |
#include "acelp.h" | |
/* filter coefficients in Q12 */ | |
static Word16 a[4] = {8192, 21663, -19258, 5734}; | |
static Word16 b[4] = {-3432, +10280, -10280, +3432}; | |
/* Initialization of static values */ | |
void Init_Hp_wsp(Word16 mem[]) | |
{ | |
Set_zero(mem, 9); | |
return; | |
} | |
void scale_mem_Hp_wsp(Word16 mem[], Word16 exp) | |
{ | |
Word32 i; | |
Word32 L_tmp; | |
for (i = 0; i < 6; i += 2) | |
{ | |
L_tmp = ((mem[i] << 16) + (mem[i + 1]<<1)); | |
L_tmp = L_shl(L_tmp, exp); | |
mem[i] = L_tmp >> 16; | |
mem[i + 1] = (L_tmp & 0xffff)>>1; | |
} | |
for (i = 6; i < 9; i++) | |
{ | |
L_tmp = L_deposit_h(mem[i]); /* x[i] */ | |
L_tmp = L_shl(L_tmp, exp); | |
mem[i] = vo_round(L_tmp); | |
} | |
return; | |
} | |
void Hp_wsp( | |
Word16 wsp[], /* i : wsp[] signal */ | |
Word16 hp_wsp[], /* o : hypass wsp[] */ | |
Word16 lg, /* i : lenght of signal */ | |
Word16 mem[] /* i/o : filter memory [9] */ | |
) | |
{ | |
Word16 x0, x1, x2, x3; | |
Word16 y3_hi, y3_lo, y2_hi, y2_lo, y1_hi, y1_lo; | |
Word32 i, L_tmp; | |
y3_hi = mem[0]; | |
y3_lo = mem[1]; | |
y2_hi = mem[2]; | |
y2_lo = mem[3]; | |
y1_hi = mem[4]; | |
y1_lo = mem[5]; | |
x0 = mem[6]; | |
x1 = mem[7]; | |
x2 = mem[8]; | |
for (i = 0; i < lg; i++) | |
{ | |
x3 = x2; | |
x2 = x1; | |
x1 = x0; | |
x0 = wsp[i]; | |
/* y[i] = b[0]*x[i] + b[1]*x[i-1] + b140[2]*x[i-2] + b[3]*x[i-3] */ | |
/* + a[1]*y[i-1] + a[2] * y[i-2] + a[3]*y[i-3] */ | |
L_tmp = 16384L; /* rounding to maximise precision */ | |
L_tmp += (y1_lo * a[1])<<1; | |
L_tmp += (y2_lo * a[2])<<1; | |
L_tmp += (y3_lo * a[3])<<1; | |
L_tmp = L_tmp >> 15; | |
L_tmp += (y1_hi * a[1])<<1; | |
L_tmp += (y2_hi * a[2])<<1; | |
L_tmp += (y3_hi * a[3])<<1; | |
L_tmp += (x0 * b[0])<<1; | |
L_tmp += (x1 * b[1])<<1; | |
L_tmp += (x2 * b[2])<<1; | |
L_tmp += (x3 * b[3])<<1; | |
L_tmp = L_tmp << 2; | |
y3_hi = y2_hi; | |
y3_lo = y2_lo; | |
y2_hi = y1_hi; | |
y2_lo = y1_lo; | |
y1_hi = L_tmp >> 16; | |
y1_lo = (L_tmp & 0xffff) >>1; | |
hp_wsp[i] = (L_tmp + 0x4000)>>15; | |
} | |
mem[0] = y3_hi; | |
mem[1] = y3_lo; | |
mem[2] = y2_hi; | |
mem[3] = y2_lo; | |
mem[4] = y1_hi; | |
mem[5] = y1_lo; | |
mem[6] = x0; | |
mem[7] = x1; | |
mem[8] = x2; | |
return; | |
} | |