1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_lms_norm_init_q31.c
* Description: Q31 NLMS initialization function
*
* $Date: 27. January 2017
* $Revision: V.1.5.1
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* 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
*
* 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.
*/
#include "arm_math.h"
#include "arm_common_tables.h"
/**
* @addtogroup LMS_NORM
* @{
*/
/**
* @brief Initialization function for Q31 normalized LMS filter.
* @param[in] *S points to an instance of the Q31 normalized LMS filter structure.
* @param[in] numTaps number of filter coefficients.
* @param[in] *pCoeffs points to coefficient buffer.
* @param[in] *pState points to state buffer.
* @param[in] mu step size that controls filter coefficient updates.
* @param[in] blockSize number of samples to process.
* @param[in] postShift bit shift applied to coefficients.
* @return none.
*
* <b>Description:</b>
* \par
* <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
* <pre>
* {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
* </pre>
* The initial filter coefficients serve as a starting point for the adaptive filter.
* <code>pState</code> points to an array of length <code>numTaps+blockSize-1</code> samples,
* where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_lms_norm_q31()</code>.
*/
void arm_lms_norm_init_q31(
arm_lms_norm_instance_q31 * S,
uint16_t numTaps,
q31_t * pCoeffs,
q31_t * pState,
q31_t mu,
uint32_t blockSize,
uint8_t postShift)
{
/* Assign filter taps */
S->numTaps = numTaps;
/* Assign coefficient pointer */
S->pCoeffs = pCoeffs;
/* Clear state buffer and size is always blockSize + numTaps - 1 */
memset(pState, 0, (numTaps + (blockSize - 1U)) * sizeof(q31_t));
/* Assign post Shift value applied to coefficients */
S->postShift = postShift;
/* Assign state pointer */
S->pState = pState;
/* Assign Step size value */
S->mu = mu;
/* Initialize reciprocal pointer table */
S->recipTable = (q31_t *) armRecipTableQ31;
/* Initialise Energy to zero */
S->energy = 0;
/* Initialise x0 to zero */
S->x0 = 0;
}
/**
* @} end of LMS_NORM group
*/
|
