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