1 /*-----------------------------------------------------------------------------
2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
4 * $Date: 17. January 2013
7 * Project: CMSIS DSP Library
8 * Title: arm_lms_norm_init_q31.c
10 * Description: Q31 NLMS initialization function.
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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15 * modification, are permitted provided that the following conditions
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25 * software without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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39 * ---------------------------------------------------------------------------*/
42 #include "arm_common_tables.h"
45 * @addtogroup LMS_NORM
50 * @brief Initialization function for Q31 normalized LMS filter.
51 * @param[in] *S points to an instance of the Q31 normalized LMS filter structure.
52 * @param[in] numTaps number of filter coefficients.
53 * @param[in] *pCoeffs points to coefficient buffer.
54 * @param[in] *pState points to state buffer.
55 * @param[in] mu step size that controls filter coefficient updates.
56 * @param[in] blockSize number of samples to process.
57 * @param[in] postShift bit shift applied to coefficients.
62 * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
64 * {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
66 * The initial filter coefficients serve as a starting point for the adaptive filter.
67 * <code>pState</code> points to an array of length <code>numTaps+blockSize-1</code> samples,
68 * where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_lms_norm_q31()</code>.
71 void arm_lms_norm_init_q31(
72 arm_lms_norm_instance_q31
* S
,
80 /* Assign filter taps */
83 /* Assign coefficient pointer */
86 /* Clear state buffer and size is always blockSize + numTaps - 1 */
87 memset(pState
, 0, (numTaps
+ (blockSize
- 1u)) * sizeof(q31_t
));
89 /* Assign post Shift value applied to coefficients */
90 S
->postShift
= postShift
;
92 /* Assign state pointer */
95 /* Assign Step size value */
98 /* Initialize reciprocal pointer table */
99 S
->recipTable
= (q31_t
*) armRecipTableQ31
;
101 /* Initialise Energy to zero */
104 /* Initialise x0 to zero */
110 * @} end of LMS_NORM group