1 /*
2 ** Copyright 2003-2010, VisualOn, Inc.
3 **
4 ** Licensed under the Apache License, Version 2.0 (the "License");
5 ** you may not use this file except in compliance with the License.
6 ** You may obtain a copy of the License at
7 **
8 ** http://www.apache.org/licenses/LICENSE-2.0
9 **
10 ** Unless required by applicable law or agreed to in writing, software
11 ** distributed under the License is distributed on an "AS IS" BASIS,
12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 ** See the License for the specific language governing permissions and
14 ** limitations under the License.
15 */
16
17 /***********************************************************************
18 * File: hp_wsp.c *
19 * Description: *
20 * 3nd order high pass filter with cut off frequency at 180Hz *
21 * Algorithm: *
22 * *
23 * y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2] + b[3]*x[i-3] *
24 * + a[1]*y[i-1] + a[2]*y[i-2] + a[3]*y[i-3]; *
25 * *
26 * float a_coef[HP_ORDER]= { *
27 * -2.64436711600664f, *
28 * 2.35087386625360f, *
29 * -0.70001156927424f}; *
30 * *
31 * float b_coef[HP_ORDER+1]= { *
32 * -0.83787057505665f, *
33 * 2.50975570071058f, *
34 * -2.50975570071058f, *
35 * 0.83787057505665f}; *
36 * *
37 *************************************************************************/
38
39 #include "typedef.h"
40 #include "basic_op.h"
41 #include "oper_32b.h"
42 #include "acelp.h"
43
44 /* filter coefficients in Q12 */
45 static Word16 a[4] = {8192, 21663, -19258, 5734};
46 static Word16 b[4] = {-3432, +10280, -10280, +3432};
47
48 /* Initialization of static values */
Init_Hp_wsp(Word16 mem[])49 void Init_Hp_wsp(Word16 mem[])
50 {
51 Set_zero(mem, 9);
52
53 return;
54 }
55
scale_mem_Hp_wsp(Word16 mem[],Word16 exp)56 void scale_mem_Hp_wsp(Word16 mem[], Word16 exp)
57 {
58 Word32 i;
59 Word32 L_tmp;
60
61 for (i = 0; i < 6; i += 2)
62 {
63 L_tmp = ((mem[i] << 16) + (mem[i + 1]<<1));
64 L_tmp = L_shl(L_tmp, exp);
65 mem[i] = L_tmp >> 16;
66 mem[i + 1] = (L_tmp & 0xffff)>>1;
67 }
68
69 for (i = 6; i < 9; i++)
70 {
71 L_tmp = L_deposit_h(mem[i]); /* x[i] */
72 L_tmp = L_shl(L_tmp, exp);
73 mem[i] = vo_round(L_tmp);
74 }
75
76 return;
77 }
78
79
Hp_wsp(Word16 wsp[],Word16 hp_wsp[],Word16 lg,Word16 mem[])80 void Hp_wsp(
81 Word16 wsp[], /* i : wsp[] signal */
82 Word16 hp_wsp[], /* o : hypass wsp[] */
83 Word16 lg, /* i : lenght of signal */
84 Word16 mem[] /* i/o : filter memory [9] */
85 )
86 {
87 Word16 x0, x1, x2, x3;
88 Word16 y3_hi, y3_lo, y2_hi, y2_lo, y1_hi, y1_lo;
89 Word32 i, L_tmp;
90
91 y3_hi = mem[0];
92 y3_lo = mem[1];
93 y2_hi = mem[2];
94 y2_lo = mem[3];
95 y1_hi = mem[4];
96 y1_lo = mem[5];
97 x0 = mem[6];
98 x1 = mem[7];
99 x2 = mem[8];
100
101 for (i = 0; i < lg; i++)
102 {
103 x3 = x2;
104 x2 = x1;
105 x1 = x0;
106 x0 = wsp[i];
107 /* y[i] = b[0]*x[i] + b[1]*x[i-1] + b140[2]*x[i-2] + b[3]*x[i-3] */
108 /* + a[1]*y[i-1] + a[2] * y[i-2] + a[3]*y[i-3] */
109
110 L_tmp = 16384L; /* rounding to maximise precision */
111 L_tmp += (y1_lo * a[1])<<1;
112 L_tmp += (y2_lo * a[2])<<1;
113 L_tmp += (y3_lo * a[3])<<1;
114 L_tmp = L_tmp >> 15;
115 L_tmp += (y1_hi * a[1])<<1;
116 L_tmp += (y2_hi * a[2])<<1;
117 L_tmp += (y3_hi * a[3])<<1;
118 L_tmp += (x0 * b[0])<<1;
119 L_tmp += (x1 * b[1])<<1;
120 L_tmp += (x2 * b[2])<<1;
121 L_tmp += (x3 * b[3])<<1;
122
123 L_tmp = L_tmp << 2;
124
125 y3_hi = y2_hi;
126 y3_lo = y2_lo;
127 y2_hi = y1_hi;
128 y2_lo = y1_lo;
129 y1_hi = L_tmp >> 16;
130 y1_lo = (L_tmp & 0xffff) >>1;
131
132 hp_wsp[i] = (L_tmp + 0x4000)>>15;
133 }
134
135 mem[0] = y3_hi;
136 mem[1] = y3_lo;
137 mem[2] = y2_hi;
138 mem[3] = y2_lo;
139 mem[4] = y1_hi;
140 mem[5] = y1_lo;
141 mem[6] = x0;
142 mem[7] = x1;
143 mem[8] = x2;
144
145 return;
146 }
147
148
149