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
35Word16 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
47void Init_Filt_6k_7k(Word16 mem[])         /* mem[30] */
48{
49	Set_zero(mem, L_FIR - 1);
50	return;
51}
52
53void 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