| /* |
| ** 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; |
| } |
| |
| |