/* | |
** 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; | |
} | |