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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: deemph.c *
* *
* Description:filtering through 1/(1-mu z^ -1) *
* Deemph2 --> signal is divided by 2 *
* Deemph_32 --> for 32 bits signal. *
* *
************************************************************************/
#include "typedef.h"
#include "basic_op.h"
#include "math_op.h"
void Deemph(
Word16 x[], /* (i/o) : input signal overwritten by the output */
Word16 mu, /* (i) Q15 : deemphasis factor */
Word16 L, /* (i) : vector size */
Word16 * mem /* (i/o) : memory (y[-1]) */
)
{
Word32 i;
Word32 L_tmp;
L_tmp = L_deposit_h(x[0]);
L_tmp = L_mac(L_tmp, *mem, mu);
x[0] = vo_round(L_tmp);
for (i = 1; i < L; i++)
{
L_tmp = L_deposit_h(x[i]);
L_tmp = L_mac(L_tmp, x[i - 1], mu);
x[i] = voround(L_tmp);
}
*mem = x[L - 1];
return;
}
void Deemph2(
Word16 x[], /* (i/o) : input signal overwritten by the output */
Word16 mu, /* (i) Q15 : deemphasis factor */
Word16 L, /* (i) : vector size */
Word16 * mem /* (i/o) : memory (y[-1]) */
)
{
Word32 i;
Word32 L_tmp;
L_tmp = x[0] << 15;
L_tmp += ((*mem) * mu)<<1;
x[0] = (L_tmp + 0x8000)>>16;
for (i = 1; i < L; i++)
{
L_tmp = x[i] << 15;
L_tmp += (x[i - 1] * mu)<<1;
x[i] = (L_tmp + 0x8000)>>16;
}
*mem = x[L - 1];
return;
}
void Deemph_32(
Word16 x_hi[], /* (i) : input signal (bit31..16) */
Word16 x_lo[], /* (i) : input signal (bit15..4) */
Word16 y[], /* (o) : output signal (x16) */
Word16 mu, /* (i) Q15 : deemphasis factor */
Word16 L, /* (i) : vector size */
Word16 * mem /* (i/o) : memory (y[-1]) */
)
{
Word16 fac;
Word32 i, L_tmp;
fac = mu >> 1; /* Q15 --> Q14 */
L_tmp = L_deposit_h(x_hi[0]);
L_tmp += (x_lo[0] * 8)<<1;
L_tmp = (L_tmp << 3);
L_tmp += ((*mem) * fac)<<1;
L_tmp = (L_tmp << 1);
y[0] = (L_tmp + 0x8000)>>16;
for (i = 1; i < L; i++)
{
L_tmp = L_deposit_h(x_hi[i]);
L_tmp += (x_lo[i] * 8)<<1;
L_tmp = (L_tmp << 3);
L_tmp += (y[i - 1] * fac)<<1;
L_tmp = (L_tmp << 1);
y[i] = (L_tmp + 0x8000)>>16;
}
*mem = y[L - 1];
return;
}
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