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: hp6k.c *
19 * *
20 * Description:15th order band pass 6kHz to 7kHz FIR filter *
21 * frequency: 4kHz 5kHz 5.5kHz 6kHz 6.5kHz 7kHz 7.5kHz 8kHz *
22 * dB loss: -60dB -45dB -13dB -3dB 0dB -3dB -13dB -45dB *
23 * *
24 ************************************************************************/
25
26 #include "typedef.h"
27 #include "basic_op.h"
28 #include "acelp.h"
29 #include "cnst.h"
30
31 #define L_FIR 31
32
33 /* filter coefficients (gain=4.0) */
34
35 Word16 fir_6k_7k[L_FIR] =
36 {
37 -32, 47, 32, -27, -369,
38 1122, -1421, 0, 3798, -8880,
39 12349, -10984, 3548, 7766, -18001,
40 22118, -18001, 7766, 3548, -10984,
41 12349, -8880, 3798, 0, -1421,
42 1122, -369, -27, 32, 47,
43 -32
44 };
45
46
Init_Filt_6k_7k(Word16 mem[])47 void Init_Filt_6k_7k(Word16 mem[]) /* mem[30] */
48 {
49 Set_zero(mem, L_FIR - 1);
50 return;
51 }
52
Filt_6k_7k(Word16 signal[],Word16 lg,Word16 mem[])53 void Filt_6k_7k(
54 Word16 signal[], /* input: signal */
55 Word16 lg, /* input: length of input */
56 Word16 mem[] /* in/out: memory (size=30) */
57 )
58 {
59 Word16 x[L_SUBFR16k + (L_FIR - 1)];
60 Word32 i, L_tmp;
61
62 Copy(mem, x, L_FIR - 1);
63 for (i = lg - 1; i >= 0; i--)
64 {
65 x[i + L_FIR - 1] = signal[i] >> 2; /* gain of filter = 4 */
66 }
67 for (i = 0; i < lg; i++)
68 {
69 L_tmp = (x[i] + x[i+ 30]) * fir_6k_7k[0];
70 L_tmp += (x[i+1] + x[i + 29]) * fir_6k_7k[1];
71 L_tmp += (x[i+2] + x[i + 28]) * fir_6k_7k[2];
72 L_tmp += (x[i+3] + x[i + 27]) * fir_6k_7k[3];
73 L_tmp += (x[i+4] + x[i + 26]) * fir_6k_7k[4];
74 L_tmp += (x[i+5] + x[i + 25]) * fir_6k_7k[5];
75 L_tmp += (x[i+6] + x[i + 24]) * fir_6k_7k[6];
76 L_tmp += (x[i+7] + x[i + 23]) * fir_6k_7k[7];
77 L_tmp += (x[i+8] + x[i + 22]) * fir_6k_7k[8];
78 L_tmp += (x[i+9] + x[i + 21]) * fir_6k_7k[9];
79 L_tmp += (x[i+10] + x[i + 20]) * fir_6k_7k[10];
80 L_tmp += (x[i+11] + x[i + 19]) * fir_6k_7k[11];
81 L_tmp += (x[i+12] + x[i + 18]) * fir_6k_7k[12];
82 L_tmp += (x[i+13] + x[i + 17]) * fir_6k_7k[13];
83 L_tmp += (x[i+14] + x[i + 16]) * fir_6k_7k[14];
84 L_tmp += (x[i+15]) * fir_6k_7k[15];
85 signal[i] = (L_tmp + 0x4000) >> 15;
86 }
87
88 Copy(x + lg, mem, L_FIR - 1);
89
90 }
91
92
93
94