1 /* ------------------------------------------------------------------
2 * Copyright (C) 1998-2009 PacketVideo
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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
14 * See the License for the specific language governing permissions
15 * and limitations under the License.
16 * -------------------------------------------------------------------
18 /****************************************************************************************
19 Portions of this file are derived from the following 3GPP standard:
22 ANSI-C code for the Adaptive Multi-Rate - Wideband (AMR-WB) speech codec
23 Available from http://www.3gpp.org
25 (C) 2007, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
26 Permission to distribute, modify and use this file under the standard license
27 terms listed above has been obtained from the copyright holder.
28 ****************************************************************************************/
30 ------------------------------------------------------------------------------
34 Filename: highpass_50Hz_at_12k8.cpp
36 ------------------------------------------------------------------------------
37 INPUT AND OUTPUT DEFINITIONS
39 int16 signal[], input signal / output is divided by 16
40 int16 lg, lenght of signal
41 int16 mem[] filter memory [6]
44 ------------------------------------------------------------------------------
47 2nd order high pass filter with cut off frequency at 31 Hz.
48 Designed with cheby2 function in MATLAB.
49 Optimized for fixed-point to get the following frequency response:
51 frequency: 0Hz 14Hz 24Hz 31Hz 37Hz 41Hz 47Hz
52 dB loss: -infdB -15dB -6dB -3dB -1.5dB -1dB -0.5dB
56 y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2]
57 + a[1]*y[i-1] + a[2]*y[i-2];
59 int16 b[3] = {4053, -8106, 4053}; in Q12
60 int16 a[3] = {8192, 16211, -8021}; in Q12
62 float --> b[3] = {0.989501953, -1.979003906, 0.989501953};
63 a[3] = {1.000000000, 1.978881836, -0.979125977};
66 ------------------------------------------------------------------------------
70 ------------------------------------------------------------------------------
73 ------------------------------------------------------------------------------
76 ------------------------------------------------------------------------------
80 /*----------------------------------------------------------------------------
82 ----------------------------------------------------------------------------*/
85 #include "pv_amr_wb_type_defs.h"
86 #include "pvamrwbdecoder_basic_op.h"
87 #include "pvamrwb_math_op.h"
88 #include "pvamrwbdecoder_cnst.h"
89 #include "pvamrwbdecoder_acelp.h"
92 /*----------------------------------------------------------------------------
94 ; Define module specific macros here
95 ----------------------------------------------------------------------------*/
98 /*----------------------------------------------------------------------------
100 ; Include all pre-processor statements here. Include conditional
101 ; compile variables also.
102 ----------------------------------------------------------------------------*/
104 /*----------------------------------------------------------------------------
105 ; LOCAL FUNCTION DEFINITIONS
106 ; Function Prototype declaration
107 ----------------------------------------------------------------------------*/
109 /*----------------------------------------------------------------------------
110 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS
111 ; Variable declaration - defined here and used outside this module
112 ----------------------------------------------------------------------------*/
114 /*----------------------------------------------------------------------------
115 ; EXTERNAL FUNCTION REFERENCES
116 ; Declare functions defined elsewhere and referenced in this module
117 ----------------------------------------------------------------------------*/
119 /*----------------------------------------------------------------------------
120 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
121 ; Declare variables used in this module but defined elsewhere
122 ----------------------------------------------------------------------------*/
124 /*----------------------------------------------------------------------------
126 ----------------------------------------------------------------------------*/
128 void highpass_50Hz_at_12k8_init(int16 mem[])
130 pv_memset((void *)mem, 0, 6*sizeof(*mem));
133 /*----------------------------------------------------------------------------
135 ----------------------------------------------------------------------------*/
137 void highpass_50Hz_at_12k8(
138 int16 signal[], /* input/output signal */
139 int16 lg, /* lenght of signal */
140 int16 mem[] /* filter memory [6] */
144 int16 y2_hi, y2_lo, y1_hi, y1_lo, x0, x1;
147 int16 *pt_sign = signal;
157 for (i = lg; i != 0; i--)
160 /* y[i] = b[0]*x[i] + b[1]*x[i-1] + b[0]*x[i-2] */
161 /* + a[0]*y[i-1] + a[1] * y[i-2]; */
163 L_tmp1 = fxp_mac_16by16(y1_lo, 16211, 8192L);
164 L_tmp1 = fxp_mac_16by16(y2_lo, -8021, L_tmp1);
165 L_tmp2 = fxp_mul_16by16(y1_hi, 32422);
166 L_tmp2 = fxp_mac_16by16(y2_hi, -16042, L_tmp2);
171 L_tmp2 = fxp_mac_16by16(x2, 8106, L_tmp2);
172 L_tmp2 = fxp_mac_16by16(x1, -16212, L_tmp2);
173 L_tmp2 = fxp_mac_16by16(x0, 8106, L_tmp2);
176 L_tmp1 = ((L_tmp1 >> 14) + L_tmp2) << 2;
180 y1_hi = (int16)(L_tmp1 >> 16);
181 y1_lo = (int16)((L_tmp1 - (y1_hi << 16)) >> 1);
183 /* coeff Q14 --> Q15 with saturation */
184 *(pt_sign++) = amr_wb_shl1_round(L_tmp1);