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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_lms_init_q15.c
* Description: Q15 LMS filter initialization function
* $Date: 18. March 2019
* $Revision: V1.6.0
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
* Copyright (C) 2010-2019 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
* 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"
@ingroup groupFilters
@addtogroup LMS
@brief Initialization function for the Q15 LMS filter.
@param[in] S points to an instance of the Q15 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
@par Details
<code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
{b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
The initial filter coefficients serve as a starting point for the adaptive filter.
<code>pState</code> points to the array of state variables and size of array is
<code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of
input samples processed by each call to <code>arm_lms_q15()</code>.
void arm_lms_init_q15(
arm_lms_instance_q15 * S,
uint16_t numTaps,
q15_t * pCoeffs,
q15_t * pState,
q15_t mu,
uint32_t blockSize,
uint32_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(q15_t));
/* Assign state pointer */
S->pState = pState;
/* Assign Step size value */
S->mu = mu;
/* Assign postShift value to be applied */
S->postShift = postShift;
@} end of LMS group