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/*
** 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: hp6k.c *
* *
* Description:15th order band pass 6kHz to 7kHz FIR filter *
* frequency: 4kHz 5kHz 5.5kHz 6kHz 6.5kHz 7kHz 7.5kHz 8kHz *
* dB loss: -60dB -45dB -13dB -3dB 0dB -3dB -13dB -45dB *
* *
************************************************************************/
#include "typedef.h"
#include "basic_op.h"
#include "acelp.h"
#include "cnst.h"
#define L_FIR 31
/* filter coefficients (gain=4.0) */
Word16 fir_6k_7k[L_FIR] =
{
-32, 47, 32, -27, -369,
1122, -1421, 0, 3798, -8880,
12349, -10984, 3548, 7766, -18001,
22118, -18001, 7766, 3548, -10984,
12349, -8880, 3798, 0, -1421,
1122, -369, -27, 32, 47,
-32
};
void Init_Filt_6k_7k(Word16 mem[]) /* mem[30] */
{
Set_zero(mem, L_FIR - 1);
return;
}
void Filt_6k_7k(
Word16 signal[], /* input: signal */
Word16 lg, /* input: length of input */
Word16 mem[] /* in/out: memory (size=30) */
)
{
Word16 x[L_SUBFR16k + (L_FIR - 1)];
Word32 i, L_tmp;
Copy(mem, x, L_FIR - 1);
for (i = lg - 1; i >= 0; i--)
{
x[i + L_FIR - 1] = signal[i] >> 2; /* gain of filter = 4 */
}
for (i = 0; i < lg; i++)
{
L_tmp = (x[i] + x[i+ 30]) * fir_6k_7k[0];
L_tmp += (x[i+1] + x[i + 29]) * fir_6k_7k[1];
L_tmp += (x[i+2] + x[i + 28]) * fir_6k_7k[2];
L_tmp += (x[i+3] + x[i + 27]) * fir_6k_7k[3];
L_tmp += (x[i+4] + x[i + 26]) * fir_6k_7k[4];
L_tmp += (x[i+5] + x[i + 25]) * fir_6k_7k[5];
L_tmp += (x[i+6] + x[i + 24]) * fir_6k_7k[6];
L_tmp += (x[i+7] + x[i + 23]) * fir_6k_7k[7];
L_tmp += (x[i+8] + x[i + 22]) * fir_6k_7k[8];
L_tmp += (x[i+9] + x[i + 21]) * fir_6k_7k[9];
L_tmp += (x[i+10] + x[i + 20]) * fir_6k_7k[10];
L_tmp += (x[i+11] + x[i + 19]) * fir_6k_7k[11];
L_tmp += (x[i+12] + x[i + 18]) * fir_6k_7k[12];
L_tmp += (x[i+13] + x[i + 17]) * fir_6k_7k[13];
L_tmp += (x[i+14] + x[i + 16]) * fir_6k_7k[14];
L_tmp += (x[i+15]) * fir_6k_7k[15];
signal[i] = (L_tmp + 0x4000) >> 15;
}
Copy(x + lg, mem, L_FIR - 1);
}
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