The CMSIS DSP 5 library
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functions/FilteringFunctions/arm_lms_norm_init_q15.c
- Committer:
- xorjoep
- Date:
- 2018-06-21
- Revision:
- 3:4098b9d3d571
- Parent:
- 1:24714b45cd1b
File content as of revision 3:4098b9d3d571:
/* ---------------------------------------------------------------------- * Project: CMSIS DSP Library * Title: arm_lms_norm_init_q15.c * Description: Q15 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 Q15 normalized LMS filter. * @param[in] *S points to an instance of the Q15 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 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_norm_q15()</code>. */ void arm_lms_norm_init_q15( arm_lms_norm_instance_q15 * S, uint16_t numTaps, q15_t * pCoeffs, q15_t * pState, q15_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(q15_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 = (q15_t *) armRecipTableQ15; /* Initialise Energy to zero */ S->energy = 0; /* Initialise x0 to zero */ S->x0 = 0; } /** * @} end of LMS_NORM group */